Uncertainty exists over fighting composite airplane fires

c. Leeham.net

Uncertainty exists over how airport fire departments will fight fires in the new composite commercial airliners, indicating that the manufacturers still have educating to do.

A top fire official at Denver International Airport, the location of the most recent airport crash and fire in the USA, believes the coming composite-based commercial airliners will require airport fire departments to change they way they fight post-impact fires. DIA is not yet served by the Airbus A380, the only commercial plane flying with more than component parts made out of composites, and the airport is not slated to be among the first served by the Boeing 787—due to enter service in early 2010.

But a platoon captain with the Los Angeles Fire Department stationed at LAX Airport, one of two US airports currently receiving service from an airliner with substantial composite construction (the A380; New York’s JFK is the other), says his airport follows substantially the same guidelines established for fighting post-impact fires of current generation airplanes.

And Boeing told the airport authorities at Everett, WA’s, Paine Field, where the 787 will perform its flight testing, that there isn’t any effective difference between a composite airplane and a traditional one.

Bill Davis, assistant fire chief of the Denver Fire Department assigned to the Denver International Airport, believes tactics have to be changed after reviewing the post-impact fire analysis of the US Air Force Northrop Grumman B-2A bomber in Guam February 23, 2008. The USAF issued its crash report in June 2008.

“This will fundamentally change everything from strategy and tactics and equipment,” Davis said. “It strikes me that we’re definitely going to have to train to and equip ourselves differently. I’ve studied fires in military composites. This (B-2A crash) is the first of an all-composite airplane; usually there are just parts that are composites.”

David Waggoner, the airport director at Paine Field, said that Boeing advised the airport fire officials to “treat the 787 like any other airplane. The fire department has been briefed by Boeing and they said not all composites act the same. The 787 composites don’t act the same as the composites in the B-2.”

In a statement to Leeham.net, Boeing had this to say:

Boeing has done extensive testing on the properties of the composite materials being used on board the 787 and its reaction in both in-flight fire and post-crash fire scenarios. Boeing has found – and by law must demonstrate to the FAA – that the 787 will be as safe, or safer than, today’s airplanes. The composites used on the 787 demonstrate performance that meets those requirements. Our testing also shows emergency responders will not need special gear, equipment or knowledge to effectively deal with a 787 event.

Among our findings in testing using FAA-approved methodologies were:
• The composite materials used for the 787 do not propagate an in-flight fire.
• The fuselage skin is an excellent fire barrier, and resists flame penetration far longer than an aluminum fuselage
• The toxic gas levels produced in a post-crash fire scenario are similar for both a composite fuselage and an aluminum fuselage
• There was no prolonged burning or re-ignition of the composite skin after tests were completed.

Capt. Rich Hanson, station commander of Platoon C at one of the four fire stations located at LAX Airport, said that every aircraft has some composite. “Quantity doesn’t make a difference, not really—you use the same fire fighting components.”

LAX uses what’s called Purple K, a dry power injected into the turrets that chemically puts out the fire and cools its.

Hanson said that Airbus and Boeing provided LAX with information “about how we can best attack a fire. Even with composites, it’s really not that much different than what we do anyway. Our first concern is the passengers, and we deal with any fire as hazmat and have a decontamination process before getting to hospital.”

At Denver International Airport, a Continental Airlines Boeing 737-500 aborted its take-off December 21, 2008, left the runway and caught fire. All on board escaped but 38 passengers were injured. The 737 was destroyed by the fire. (A Continental Connection Bombardier Q400 since then crashed into a house on approach to the Buffalo, NY, airport.)

The 737 is the standard metal fuselage that has been used on commercial airliners since the introduction of the Ford Tri-Motor in 1925. The new 787, scheduled to enter flight testing during the second quarter this year, has a composite fuselage, with approximately 50% of the airplane by weight made out of composites. The proposed Airbus A350, with a planned entry-into-service in 2013, also has a composite fuselage with 53% of the airplane by weight to be composite.

With these two airplanes gathering all the headlines, overlooked is that the A380 has already entered service. The super-jumbo’s rear fuselage, comprising 25% of the airplane’s weight, is made of composite materials.

As the 787 proceeds on its final countdown toward its flight-test program, certification and delivery, the debate over the safety, flammability and survivability of its composite fuselage continues at the Federal Aviation Administration.

Industry engineers concerned about the safety of the airplane continue to file reports and documents with the agency and whether the FAA has done—and is doing—enough to ensure the safety of passengers in the event of a crash and post-impact fire.

The high-profile 787 gets this attention because of its revolutionary all-composite fuselage, the open comment process that is part of the FAA procedures, the media obsession with anything involving commercial aviation safety and the embarrassing production difficulties that makes the 787 fodder for minutiae reporting..

Composites have been on airplanes for decades, as the two fire officials pointed out. Wing-to-body fairings, rudders and—on the Airbus A300-600 and A310—the entire tail sections are composites. Interior components contain composites.

But planes built largely of composites aren’t new, either. Furthermore, although wide-spread, some autos have been built of composites, notably some race cars. Firefighters have had to deal with blazes involving composites for decades.

Beech built the Starship personal aircraft out of composite materials and its successor, Raytheon, built the Premier business jet out of the same materials. No Starship crashed and burned and there were a few Premier accidents involving fires. New, personal jets such as the Eclipse, have composite fuselages. Airliners with composite components have crashed and burned. But with the development of the 787, and the FAA certification process, the prospect of a major accident and fire received some headlining attention. Dan Rather, the former CBS anchorman who was disgraced in a reporting scandal over ex-President George W. Bush’s military service record, went to HDNet, an obscure start-up cable network, and put together a long story on 787 composite safety. He relied upon a former Boeing engineer who, while raising legitimate questions, nonetheless was largely discounted because it was the recently embarrassed Rather who reported the story.

The focus on the current debate is the sheer volume, the entire fuselage, of composites on the 787, and whether firefighters, passengers and anyone downwind might be at risk of burn rates and toxicity associated with composites.

Another engineer, who did not participate in the Rather report, whose expertise is composites, continued to pepper the FAA with comments about the 787 well into this year. Derek Yates has a long list of correspondence with the FAA. Yates has urged the FAA to require fire testing with an entire center fuselage section to assess burn and hazmat issues. He believes the burn rate and toxicity issues with composites elevates the levels of danger to first responders and passengers alike, and cites the USAF B-2A analysis as evidence. FAA standards and Boeing tests so far have been inadequate, he believes.

Jim Helms, of the engineering consulting firm TATSCO and a former FAA Designated Airworthiness Representative, does not believe an Advanced Carbon Material airplane meets flammability airworthiness standards. He believes the danger so great that, radically, he thinks the entire 787 program should be cancelled. Helms recently published a four page analysis, Part 1 of 2, newsletter looking at the pros and cons of composites. This may be downloaded: TATSCO Composite Newsletter.

The issue of a large airplane composite fire took on new meaning with a real-life example, rather than a theoretical test, when the B-2A bomber crashed and burned on take-off at a US military base in Guam. The billion dollar aircraft stalled in an extreme nose-up attitude right after take-off and pancaked into the ground. The crew ejected safely; the airplane caught fire on impact. The entire accident was captured on a security camera. The cause of the crash was determined to be a critical instrument failure.

Boeing was a sub-contractor on the B-2 program, giving the company intimate knowledge of composites.

The B-2 accident was the first of a large composite airplane; the B-2’s empty weight is 158,000 lbs (slightly smaller than a Boeing 767-200) vs 252,000 lbs for the 787-8, 796,000 lbs for the A380 and 382,500 lbs for the A350-800.

The Air Force’s post-impact fire analysis reports that firefighters began pouring water the on the B-2 bomber less than three minutes after the accident. Within 30 minutes, every fire fighter on the base—53 of them—and all apparatus was on the scene. Four fire trucks were brought in from off base. The fire burned for 4-6 hours and, in the words of the report, the “complete combustion event did not end until day two and possibly day three.”

The base’s fire department used 83,000 gallons of water and 2,500 gallons of aqueous film-forming foam “with not much success in completely putting out the final combustion stage.”

Chief Davis, the Denver Airport fire official, said the use of 83,000 gallons of water was an astonishing amount. His firefighters used far less on the 737-500 (which at 103,000 lbs empty weight is 46% smaller than the B-2).

“We used 12,000 gallons, and that was excessive amount of water and foam” Davis said. “We did because I had the luxury of it. We could have been effective with close to half that amount.”

The large amount of water required to put out the fire on the B-2 means airports have to rethink how they provide water supplies for firefighting, said Davis.

“Water supply and agent conservation will be at a premium for fighting a composite aircraft. They went through tons of water, 83,000 gallons of water,” Davis said. “That’s a huge amount of water. Most every airport would have to have one of two things: hydrants throughout the airport or a very, very large Airport Resource Firefighting apparatus (ARF),” a truck with extremely large water capacity, and a very sophisticated shuttle operation.

The Air Force’s report concluded that “There was a change in the nature of burning as JP-8 was consumed. The aircraft structure continued to burn. The fire scenario could be explained in four distinct combustion stages: 1) 20-30 minutes for the JP-8 flaming combustion. 2) 4-6 hours for aircraft structure flaming combustion which transitioned to intermittent flare up at random locations across the aircraft. 3). 24 hours into the intitial response, cool down was taking place through-composite-thickness with indications of deep-seated smoldering and 4) 48 hours into the initial response, the final cool-down stage was reached with a hint of light smoke being released.”

By comparison, the Continental 737 fire was knocked down quickly and hot spots occurred over a much short time span, Denver’s Davis said.

The initial body of fire was very significant and it was knocked down almost immediately. “The exterior fire knocked was down within a minute by large caliber monitors 1200 GPM turrets as far as the large body of fire on the right side of the aircraft,” Davis said. “But there was still a significant fire underneath the aircraft and in the interior.”

The interior fire was knocked down within 15 minutes of response notification using 1 ¾ inch hoses and flowing A triple F foam.

The Continental accident occurred at 6:18 pm; there was a rekindling about 4am.

LAX’s Hanson didn’t draw a comparison with previous LAX accidents with the B-2A fire, but he pointed out that crashes involving conventional metal airplanes can have their own challenges. In a highly unusual accident in 1991, a US Air Boeing 737 landed on top of a SkyWest Airlines 19-seat Metro commuter plane waiting to take off on the same runway. The resulting fire took a long time to get the fire out because firefighters couldn’t get to smaller aircraft underneath the 737.

Hanson said that one of the things that emerged from this crash was the acquisition of a snozzle, a fire truck with a 50 ft articulating boom with hardened steel tip and titanium barrel that can penetrate the skin of the aircraft when the barrel is extended.

Snozzle of the Ft. Worth (TX) Fire Department. Source: Bensware.com.

Penetrating the skin of a metal or composite aircraft requires high pressure water. The two snozzles used by LAX are capable of 25,000 psi. A standard metal aircraft, such as those in service today, require 5,000 psi to penetrate the skin. Hanson says the GLARE composition used on portions of the A380 requires 6,000 psi and Boeing advised its 787 fuselage requires 8,000 psi. GLARE is a combination of aluminum and composite material.

Once the skin is penetrated, the snozzle’s barrel can be inserted into the airplane, discharging 250 gallons per minute, enough to hold the fire until firefighters can get the hand lines in.

“The biggest concern we had with composite is when you penetrate the fuselage, the direction of the fibers pushing in would grab the barrel. Boeing has done testing and found that isn’t a concern,” Hanson said.

The B-2 fire reached temperatures of 900-1,700 degrees, depending on the location, the Air Force concluded. JP-8 fireballs can reach temperatures in excess of 2,000 degrees.

The Air Force concluded that the “length of time needed to extinguish the fire and cool the aircraft was unexpected.” The report noted that the lengthy duration required trucks to leave the scene for water, “interrupting the suppression or cool-down process, allowing heat to penetrate and burn through thickness (layer-by-layer). Without having adequate water pressure or a water source near by, the structure was not continuously cooled through composite thickness….”

The Air Force explained that the nature of composite construction lay behind the lengthy fire and smoldering. The layer-by-layer manufacturing to the desire shape and thickness, made up of resin-coating fibers, causes the flames to burn through layer-by-layer. “Cooling or flame suppression occurs in the same manner.”

“During the initial response, the aircraft composite material concern is the resin, not carbon fiber,” the Air Force said.

Davis, the Denver fire chief, expressed concern about the particulates emitted in a composite fire.

“The smoke that comes off a composite fire is extremely toxic. The difference between [metal and composite fires] is you also get those fibers. When the composite is degraded by the fire, it releases physical fibers that become airborne and are extremely carcinogenic. It’s as bad or worse than asbestos,” Davis said.

LAX’s Hanson also compared composite fibers with asbestos and said LAX firefighters have to treat composites within the department’s Standard Operating Guidelines.

The Air Force also noted that “aircraft composite fires differ from metal aircraft fires because they add fuel to the fire by increasing the fuel load. In order to extinguish a composite fire, firefighters have to consider composite thickness and maintaining a continuous supply of agent.” The Air Force recommended specific composite fire fighting training.

The post-crash environmental clean-up is also a concern. Davis said DIA moved tons of dirt for environmental clean up, with a large amount of fuel soaking into the ground—the plane was fueled for take-off, as was the B-2A. DIA dug a 24 ft hole to remove dirt.

The B-2’s composite structure poses additional hazards. The Air Force conducted repeated tests of the surrounding ground and air to determine if there were any hazardous materials from the composites remaining after the fire.

Denver’s Davis also notes that new fire fighting equipment will be needed to deal with composite airplane crashes. New gear will be needed to cut, move and pry the composites, which have different properties than metal. New techniques will have to be adopted as a result of the toxicity of the composite smoke and particulates, especially the airborne fibers.

The Federal Aviation Administration imposed special conditions on the 787 testing that Boeing has to meet in order to certify the 787. Among them are conditions relating to composite burning and fire.

In response to questions for this article, the FAA said it is “aware of the B-2 accident, although as is often the case with accidents involving military aircraft, we do not know what payload or other items were carried on the airplane that may have contributed to the sustained fire.”

The FAA noted that “there is already extensive use of composite materials on commercial airplanes. On the exterior, fairings are often composite, as well as certain control surfaces. In addition, the interiors have for many years used significant amounts of composite materials. Therefore, virtually any post crash fire that threatens survivability will involve composite materials.

“The standards that the FAA has established for the 787 are intended to provide sufficient time for occupants to safely evacuate the airplane following an emergency situation. FAA research shows that the composite fuselage material significantly increases the time it takes for a post crash fire to burn through to the interior, which increases the time for occupants to evacuate before the exterior fire can endanger them.”

As for environmental and fire fighting issues, the FAA says this is beyond its scope for certification.

“The concerns raised regarding fire fighting and potential environmental ramifications of composite airframes are not airworthiness issues. Nonetheless, the FAA is working with the Air Force on future studies to assess these and other post crash fire topics that are outside the airworthiness approval process. At this point, we can’t forecast where these studies may lead.”

LAX’s Hanson said, “We feel very comfortable with our ability to deal with a fire in any of the current of upcoming aircraft. Boeing knows what our resources are and in discussion with their training people I am very comfortable we are where we need to be to deal with an incident at LAX.”

Airbus, like Boeing, was asked February 5 by Leeham.net to respond to the B-2A USAF post-impact fire analysis. We’re still waiting for a response.

The USAF post-impact fire analysis may be downloaded: B-2A Post-Impact Fire Analysis. 6 pages, PDF.

12 comments on “Uncertainty exists over fighting composite airplane fires

  1. FAA & BOEING’S POSITION ON 787’s Fire-Worthiness is self serving and criminal.
    Students at the US Navy Post Graduate School, Monterey, California, have published at least two documents pertaining to “Fire- Worthiness that support the USAF accident report. (I think the first report was produced almost 20 years ago – it addresses the composite sturucture on combat ships as well as the composite material on carrier based aircraft.) The Australian Civil Aviation Authority has published a Document that is distributed to every airport and first responder to aircraft crashes in the country – and they are addressing composite airplanes – from gliders to transports. Do a “google”, Advanced Composite Airplanes and Fires . . . By the way, the biggest farse is the Boeing/FAA fire curtain that will be intalled in some – not all – lower fuselage areas of the 787. Look at the 737NG that crashed at AMS . . . . The fuselage was “torn open” in several areas.

    Remember when ROLL ROYCE built a composite fan and other compressor parts of Composites for the L-1011 airliner. Worked fine until the bird hit the fan – almost shot down the “1011 program” as they switched to titanium. The same thing would happen to the 787 program if the FAA required the test thaat Derek Yates and other concerned experts have suggested. Current ACMs burn and produce toxic smoke and they require truckloads of water to extinguish the fire.

    JIM HELMS
    jim@tatsco.com

  2. Well done, Scott and I found Boeing’s response typically evasive as has been the case over the past several years. They talk of “by law must demonstrate to the FAA’, whilst largely writing the regulations themselves. They are also very evasive in discussing composite fires by narrowing to skins rather than all structures. It was the thick and heavy wing box and carry-through structures that caused the USAF to have to fight the B-2A fire for two to three days due to flare-ups caused by epoxy between layers igniting and burning. And the statement that “No special equipment is needed for 787 fires” is patently ludicrous and incorrect as anybody studying the crash photos and H-2 section (Impact Analysis) of the USAF B-2A Guam crash can attest. Next the USAF should not have been too surprised at the extent, duration and flare ups experienced in Guam crash as AFML tested such composite wing boxes in 2004 and experienced long lasting flares ups akin to the Guam crash. The fact is that epoxies are flammable and the fire source as the USAF report states and no PR twittering from Boeing can evade the issue.
    In addition, there is the A380 CF/Epoxy center wing box to fret about, beyond GLARE and the rear fuselage. What about a wheels up landing or worse?
    Obviously FAA should edict and Boeing should and must perform a ruptured fuselage fuel fed fire instrumented FST test, just as occurred in the Malton, Toronto A340 AF crash and as I have been demanding of them and FAA for years. The fact is that in most survivable crashes on landing or take off, fuselages rupture, and toxic gases enter interiors, such fuselage ruptures occurred on Continental 737 in Denver (with Fire) and at Amsterdam re Turkish Air recently (without fire). I have sent to both FAA and Boeing records of over sixty survivable commercial crashes, ALL of which had ruptured fuselages in survivable crashes.
    A ruptured fuselage is the rule rather than the exception and the refusal by Boeing and FAA to conduct such a test speaks volumes regarding their fear of the results of such a test.

  3. Scott,
    You might also check the September 2008 Flight Safety article re composite fire dangers also and well as Dr. Adrian Mouritz’s report for Australian board, ATSB.

  4. We read the Flight Safety article before writing this one and had previously scanned the lengthy ATSB document.

    What is key from our article is what the airport fire departments say. There remains a difference of opinion and uncertainty. That has to be addressed.

    The FAA is going to do what the FAA is going to do.

  5. COMPOSITE MATERIALS DO BURN . . . An FAA conference at the FAA Technical Center – Atlantic City — on November 18, 1998 reported . . . . Current aircraft design utilizes several tons of combustible plastics for cabin interior components that includes the passenger compartment, cockpit and cargo compartments. This is a fire load comparable to the equivalent weight of aviation fuel. THE FAA HAS ISSUED RULE CHANGES AND AIRWORTHINESS DIRECTIVES TO ELIMINATE THESE COMBUSTIBLE PLASTICS INSIDE THE AIRCRAFT, BUT THEY ARE ABOUT TO APPROVE A PLASTIC AIRPLANE THAT WILL HAVE MORE THAN 50 TONNES OF FLAMMABLE MATERIAL IN THE PRIMARY STRUCTURE, WING, EMPENNAGE AND FUSELAGE SKIN.

    MIL-HDBK-17-1F becomes a part of this comment because it was referenced by BOEING ENGINEERS in a paper presented at the 11th International Conference on Composite Materials (ICCM-11), Australia, July 14-18, 1997

    777 EMPENNAGE CERTIFICATION APPROACH
    A. Fawcettl, J. Trostle, S. Ward 777 Program, Structures Engineering, Principal Engineer and DER 777 Program, Structures Engineering, Manager Composite Methods and Allowables, Principal EngineerBoeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington, USA

    If you aren’t familiar with it . . . . MIL-HDBK-17, also known as the Composite Materials Handbook, is the primary and authoritative source for statistically based characterization data of current and emerging composite materials, reflecting the best available data and technology for testing and analysis, and including data development and usage guidelines. The handbook provides the information and guidance necessary to design and fabricate end items from composite materials. Its primary purpose is the standardization of engineering data development methodologies related to testing, data reduction, and reporting of property data for current and emerging composite materials.

    In support of this objective, the handbook includes composite materials properties that meet
    specific data requirements. The handbook therefore constitutes an overview of composites technology and engineering, an area that is advancing and changing rapidly. As a result, the
    document is constantly changing as sections are added or modified to reflect advances in the
    state-of-the-art.

    The overall effort is co-chaired by Gary Hagnauer, U. S. Army Research Laboratory (ARL), and
    Joseph Soderquist, Federal Aviation Administration (FAA).

    The handbook, which has since been superseded for civil aircraft, states . . . .

    6.6.18 Flammability and smoke generation
    6.6.18.1 Introduction
    A significant concern in any application of organic matrix based composites in occupied spaces is the possibility that an accidental (or deliberate) fire may impinge on the structure. This is potentially problematical for two reasons. First, heat weakens the polymer binder. Thermoplastic binders begin to creep and then to flow as the impinging flames raise their local temperature past the glass transition temperature. Thermoset binders degrade to a char or gasify or both. The functioning of the binder is thus diminished and the composite loses strength. If the structure is one in which the composite forms only a secondary or repair role, the consequences of a local, heat-induced composite failure are not likely to be serious; time is available to repair the damaged material. However, if the affected composite component is part of a primary critical structure, such as the wing of an aircraft, the structure may collapse.

    The second aspect of the problem can greatly magnify the first. The binder may ignite and support the spread of flame on the composite surface and also release heat and generate potentially toxic smoke. Thus the localized, external fire may cause a larger structural fire involving the composite which now becomes the fuel for the growing fire. In confined or enclosed spaces such as ships and aircraft, the growing fire could lead to a flashover condition in which all combustible materials within the enclosure begin burn.

    OUR NEXT COMMENT WILL ADDRESS SMOKE, A “BY PRODUCT” OF COMBUSTION.

    Jim Helms

  6. COMPOSITE AIRCRAFT FIRE FIGHTING . . . . We encourage the Fire Department at Paine Field to “look beyond the assurance” of their “tenant” . . . . to someone without a “horse in the race!”
    THE FAA AIRPORT TECHNOLOGY – RESEARCH AND DEVELOPMENT BRANCH IN ATLANTIC CITY, ON A WEB SITE LAST UPDATED ON 12/01/2006 STATED . . . Research conducted to date shows that some composite materials sustained significant damage after only 10 seconds of heat exposure.
    Composite fires tend to be deep seated (similar to a charcoal fire), continue to smolder internally and require copious amounts of water to fully extinguish. Tests conducted by the Air Force have shown that fires can continue to burn internally even when the exterior fire has been fully suppressed. If not completely cooled, the epoxy resins in the composite will smolder, which can potentially reignite fuel and other flammable materials in the area. Firefighters need to receive instruction specific to composite materials so that they can learn to identify composites on the aircraft, train to effectively extinguish these fires and determine when the interior has been cooled below the reignition temperature. The FAA is initiating several new areas of research specifically to address issues related to ARFF response to composite fires including:

    What is the best extinguishing agent?

    What is the best extinguishing method?

    How much agent is required?

    How long do agents need to be applied to extinguish such a fire?

    Does any additional hazard exist for fuel stored in composite aircraft wings?

    Do ARFF personnel posses the correct tools and equipment to mitigate a composite fire?

    As noted in Scott’s article . . . .The test conducted by the USAF appears to have been validated with the crash of the B-2A on Guam – 23 February 2008 – when copious amounts of water (83,000 gallons of water containing 2,500 gallons of aqueous film-forming foam (AFFF)) were applied, with not much success in completely putting out the final combustion stage.

    FURTHER COMMENTS – WINDOWS, SMOKE AND TOXICITY WILL FOLLOW.

  7. Subject: THE WINDOWS, AN ALTERNATE MEANS OF TOXIC SMOKE ENTERING THE PASSENGER CABIN

    PASSENGER CAIN WINDOWS
    The CAL – DEN accident where fire breached the RH FUSELAGE and caused burning of interior materials caused me to look further into aircraft windows. NOTE: Some credit must be given to the 6 deadheading CAL crew members in the passenger cabin when the aircraft crashed on takeoff – providing 10 trained people to assist with the evacuation.

    My first “finding” was the FAA’s National Aviation Facilities Experimental Center (at Atlantic City) – NAFEC TECHNICAL LETTER REPORT, N/A- 80-17-LR dated MAY 1980. The topic was PRELIMINARY EVALUATION OF THE PERFORMANCE OF ADVANCED AND CONVENTIONAL AIRCRAFT WINDOWS IN A MODEL FIRE ENVIRONMENT. The Conclusions were. . .
    1. The state-of-the-art stretched acrylic windows fail by shrinking and falling out of place and not by burn through. Failure generally occurs around 100 seconds into a test (airliner aircraft evacuation time is 90 seconds).
    2 The advanced epoxy/polycarbonate windows perform as desired and appear to prevent significant fire penetration for at least 4 minutes. The failure mode involves gradual conductive heating through the epoxy char polycarbonate structural ply which then melts and falls away.

    The test model was a four foot-diameter model fuselage with an 8-foot-square pool fire adjacent to it. “The glass transition temperature (Tg)
    of acrylic will usually be around 230 deg F., while that of polycarbonate is around 300 deg F. When the backface temperature on either material approaches Tg, failure occurs. I understand the proposed Plastic Airplane uses the Advanced material.

    Now let’s take a few minutes to review the report of an actual full scale fire “test” with a 737 wing tank of fuel – 4,590 Kg. (1,507 gallons). The “specimen” was British Air Tours Boeing 737-236, certified to 14 CFR Part 25, registration G-BGJL. Some would call this a “full scale pool fed fire”.

    “The flames were seen to cause some ‘cracking and melting’ of the windows, with some associated smoke in the aft cabin before the aircraft stopped. These effects, with the accompanying radiant heat, caused some passengers to stand up in alarm.”

    “All three panels were missing from most of the window apertures in the rear cabin; some panels had remained in position in the three apertures immediately forward of the L2 door and the partially burnt remains of all three panels were still present in the aperture immediately forward of the R2 door. In the centre and forward sections of the cabin most window apertures had one or more panels present.”

    “More observations of fire in the aft/centre cabin were reported by passengers before they evacuated from the forward exits. A passenger from 8D recalled looking around after the aircraft had stopped and seeing huge tongues of flame shooting into the cabin through the windows of the fuselage on the left side. He stated that flames commenced at the first window past the central emergency hatch with six or seven windows behind thus affected. The flames were lapping up to the ceiling. Several people who were in seats nearest these windows were seen engulfed in flames.”

    “Some witnesses spoke of the fire penetrating the windows very early. However, the weight of evidence from previous research into window fire penetration suggests that the type of window fitted to G-BGJL should typically withstand a pooled fuel fire for at least 40 seconds, and
    possibly would present a barrier to the fire for 60 to 90 seconds,”

    FIRE HARDENING . . . MUCH WORK IS NEEDED
    “In contrast to the extensive research into fire hardening interiors, research into fire hardening of the hull itself has been much more limited. Mainly, this work has been directed towards obtaining data on fuselage skin penetration times and improving the fire resistance of windows and their fixing systems. Whilst it is understood that manufacturers and airworthiness authorities have devoted time and effort to the effects of fire on the fuselage structure, there is little evidence that fuselage penetration by an external fire, or the subsequent transmission of that fire through the internal structure, has been addressed with anything like the vigour applied to the fire hardening of interior materials. The question therefore arises as to whether the balance of effort between work on fire hardening interiors and improving the fire resistance of the hull itself is appropriate, particularly in the light of the Manchester experience.”

    The purpose of these comments regarding windows is to illustrate that there is an alternate means for toxic smoke from fires started before the aircraft comes to a stop to enter a passenger airliner cabin and that fire resistant lower lobe lining material is merely a “band aid” and not a solution.

    JIM HELMS

  8. SMOKE FROM A BURNING AIRCRAFT

    AS I HAVE DONE IN MY OTHER COMMENTS . . . I LET THE FAA FIRE EXPERTS HAVE THE FIRST WORD . . . . IN THIS CASE — DPT/FAA/AR-98/34 — Health Hazards of Combustion
    Products From Aircraft Composite Materials

    “To date combustion toxicology has focused on the acute and chronic effects of gases produced by the incomplete combustion of flammable materials inside a compartment. Vapors and gases vitiate a compartment and at high concentrations cause fatal or incapacitating effects among occupants.

    “The burning of fiber composites generates heat and combustion products that consist of a complex mixture of gases and visible products of incomplete combustion, collectively referred to as smoke. The nature of these products depends upon the composition of the burning material(s) and the transient thermo-oxidative conditions during the fire. Smoke composition varies significantly with the change in burning conditions and fire growth rate. At any stage of fire development, the smoke stream contains a mixture of evolved gases, vapors, and solid particles.

    Aerosols constitute the visible component of smoke and are comprise of aggregates of solid particles adsorbed with combustion vapors and gases. Aerosols (including fibers) are classified in terms of the physical nature and size of its components. Airborne particles vary widely in size from submicron to many microns. Smaller particles stay suspended in air longer and due to their greater surface area are more likely to adsorb chemical vapors from the smoke. The physiological effects of human exposure to fire effluent depends upon the size distribution and solubility characteristics of the aerosols, which determine the depth of penetration in the lungs and the degree of absorption inside the body.”

    “The Civil Aviation Authority in the United Kingdom investigated the toxic nature of combustion products from composites. Samples of composite materials used in structural components of a public transport jet aircraft and a helicopter were tested in a combustion chamber. Samples were subjected to a flaming heat source at a temperature of 1150°C ± 50°C. The chemical analysis of the combustion products via gas chromatography and mass spectroscopy revealed several organic chemicals. ”

    “US Air Force Toxicology Division conducted a series of tests using a modified University of Pittsburgh apparatus for evaluating combustion toxicity of advanced composite materials used in military aircraft. Preliminary studies focused on the morphology and chemical composition of organic compounds associated with particulates carried in the smoke affluent from burning composites. The test materials consisted of carbon fiber impregnated in a modified bismaleimide resin. SEM and digital image processing were used to determine the size distribution of particles. The analyses did not reveal the presence of any fiber-shaped particles (L/D >3). Particles were classified in terms of count median diameter, 10 mm. Larcom reported that 40 percent of the particles were of respirable dimension with aerodynamic diameter £5 mm. These fibers are small enough to penetrate the tracheobronchial airways. Approximately 15 percent of particles had an aerodynamic diameter £1 mm, which can be deposited at the alveolus. The study did not report the fiber length measurements.”

    THE ACCIDENT REPORT –

    The UK Air Accidents Investigation Branch (AAIB) has published one of the most comprehensive aircraft accident reports that I have ever reviewed. I have used it in preparing my previous comments and strongly suggest it as mandatory reading for any aviation professional. Merely google — manchester accident 1985.

    The accident occurred when the aircraft was taking off. The attempt was aborted at about 115 knots and the aircraft had taxied clear of the active runway.

    “As the aircraft turned off, a wind of 7 knots from 250° carried the fire onto and around the rear fuselage. After the aircraft stopped the hull was penetrated rapidly and smoke, possibly with some flame transients, entered the cabin through the aft right door which was opened shortly before the aircraft came to a halt. Subsequently fire developed within the cabin. Despite the prompt attendance of the airport fire service, the aircraft was destroyed and 55 persons on board lost their lives.

    The cause of the accident was an uncontained failure of the left engine, intitiated by a failure of the No 9 combustor can which had been the subject of a repair. A section of the combustor can, which was ejected forcibly from the engine, struck and fractured an under wing fuel tank access panel. The fire which resulted developed catastrophically, primarily because of adverse orientation of the parked aircraft relative to the wind, even though the wind was light.

    Major contributory factors were the vulnerability of the wingtank access panels to impact, a lack of any effective provision for fighting major fires inside the aircraft cabin, the vulnerability of the aircraft hull to external fire and the extremely toxic nature of the emissions from the burning interior materials.

    The major cause of the fatalities was rapid incapacitation due to the inhalation of the dense toxic/irritant smoke atmosphere within the cabin, aggravated by evacuation delays caused by a door malfunction and restricted access to the exits.

    “The flames were seen to cause some ‘cracking and melting’ of the windows, with some associated smoke in the aft cabin before the aircraft stopped.”

    “After the purser had confirmed the evacuation with the commander he repeated the evacuation call a number of times over the PA system. Then, as the aircraft was coming to a halt, he went to the right front (R1) door to open it and release the inflatable escape slide. The door unlocked normally but as it was moving out through the aperture the slide container lid jammed on the doorframe preventing further movement of the door. After spending a short time trying to clear the restriction he postponed further effort and crossed to the L1 door. He cracked it open, ascertained that the forward spread of the fire was slow enough to allow evacuation from that door, opened it fully and confirmed the inflation of the slide manually. This was achieved about 25 seconds after the aircraft had stopped and coincident with the initiation of foam discharge from the first fire vehicle to arrive.

    Evacuation began on the left side under the supervision of the No 4 stewardess, who had to pull free some passengers who had become jammed together between the forward galley bulkheads in order to start the flow.

    The purser returned to the R1 door, lifted the slide pack in order to close the slide container lid, and cleared the obstruction. He succeeded in opening the door about 1 minute 10 seconds (only 20 of the required 90 second evacuation time remained) after the aircraft stopped and again confirmed the automatic inflation of the slide by pulling the manual inflation handle. Evacuation was carried out from this exit supervised by the purser.

    Smoke emanating from the cabin quickly reached the galley area and became rapidly more dense and acrid. When the smoke began to threaten severe incapacitation, the forward cabin crew vacated the aircraft by the slides at their respective doors.”

    “A marked deposition of carbon particles was found within the trachea of all victims, with some congestion of the mucosa (mucus lining) in 17 cases (“marked congestion” in the case of one passenger) with many instances of “excess mucus”. The lungs of all fatalities showed marked general congestion and oedema (fluid), with carbon particles in the air passages, consistent with the inhalation of smoke. There was no evidence of organic disease which could have caused the death of any of the victims.”

    6 passengers died from direct thermal assault (burns) and the remaining 48 as a result of smoke/toxic gas inhalation.

    “As the aircraft stopped, the aft cabin was suddenly filled with thick black smoke which induced panic amongst passengers in that area, with a consequent rapid forward movement down the aisle. Many passengers stumbled and collapsed in the aisle, forcing others to go over the seat-backs towards the centre cabin area, which was clear up until the time the right overwing exit was opened. A passenger from the front row of seats looked back as he waited to exit the aircraft, and was aware of a mass of people tangled together and struggling in the centre section, apparently incapable of moving forward, he stated “people were howling and screaming”. [NOTE: At this time the smoke was coming from outside the aircraft.}

    “Shortly after the right overwing exit was opened, it was obscured by dense black smoke which came forward from the aft cabin. The smoke poured out of the over wing exit, which was on the downwind side of the fuselage. The smoke was consistently described as heavy, thick, black, acidic, toxic and very hot. As observed by the forward cabin passengers the effects of this smoke on the respiratory system was rapid and for some catastrophic. Within one or two breaths of the dense atmosphere survivors recall burning acidic attack on their throats, immediate and severe breathing problems, weakness in their knees, debilitation and in some instances, collapse. A male passenger from seat 15C recalled taking one breath which immediately produced “tremendous pain” in his lungs and a feeling that they had “solidified”.

    NOTE: READ THE NEXT PARAGRAPH CAREFULLY re However, when burnt in a real fire . . . Fire lab testing may be misleading. The Authorities were still learning – pre-1985 and it appears they may be required to learn more!

    “This regulatory approach has already led to the use of flame-retardant materials developed by the chlorination of earlier materials. However, when burnt in a real fire, many such materials were found to generate even more smoke and gas (eg hydrogen chloride) than previously. ” (Emp added)

    “Research work completed as early as 1973 into smoke emission from aircraft interior materials indicated that: “To date the major concern of those engaged in the development of fire-retardant materials has been the reduction of the ignition tendency and flame propagation. Thus, it has been possible to meet code and regulatory requirements regarding flame-spread but in the opinion of the author the total hazard resulting from incomplete combustion has been increased”.

    “This report also included the standard disclaimer used by the American Society for Testing Materials: “No direct co-relation between these tests and service performance should be given or implied”. Whilst the regulatory authorities have not yet introduced requirements for materials certification to take account of smoke and toxic/irritant gas emissions, many aircraft manufacturers already stipulate associated limitations for their materials. For example, in 1977 Boeing established goals/guidelines (the so-called “Withington” guidelines) covering smoke emission (more stringent than the limits in NPRM75-3), toxic gas emission (hydrogen cyanide, carbon monoxide, hydrogen chloride, hydrogen fluoride, sulphur dioxide + hydrogensulphide, nitrogen oxides), and flame spread index (ASTM E162). In 1978 Airbus Industrie released ATS 1000.001 covering smoke emission (using the limits in NPRM 75-3) and toxic gas emission (using the limits in Boeing’s Withington guidelines). ATS 1000.001 has subsequently also been used by Fokker and British Aerospace. McDonnell Douglas has similar criteria on smoke and toxic gas emission Whilst this type of testing represents a considerable improvement in materials certification, the radiant heat flux used to combust the material sample is still low (2.5 watts/sq cm) compared with the radiant heat from a real pooled fuel fire which can rise to14-20 watts/sq cm.“

    NOTE: None of the PBEs (smoke hoods) or the emergency megaphone were removed from their storage locations.

    THIS REPORT REFERS TO ACCIDENTS OF JET TRANSPORT BUILT BY BOEING, DOUGLAS ANND LOCKHEED FROM 1964 THRU THE DATE OF THE REPORT – 1985.

    Read the entire report. These comments have been prepared to rebut the statements made by others in the 10 March 2009 Scott Hamilton Report. AS STUFF HAPPENS — TODAY’S COMPOSITE MATERIALS BURN . . . THEY ARE SELF-SUSTAINING AND ARE CAPABLE OF AUTO-IGNITION (LIKE A DIESEL ENGINE THEY DONT NEED A SPARK TO START).

    SMOKE KILLS, SOME SMOKE KILLS BETTER THAN OTHER SMOKE.

    Next COMMENT will further cover TOXICITY!

    JIM HELMS

  9. ADDED ON APRIL 15
    FIRE, SMOKE AND TOXICITY THE
    FAA RESPONDS TO SCOTT’S QUESTIONS . . . . . The
    Federal Aviation Administration imposed special conditions on the 787 testing that Boeing
    has to meet in order to certify the 787. Among them are conditions relating to composite
    burning and fire. NOTE: You can google “faa special conditions boeing 787”. You may note
    on the google page – “Boeing 787, the new US flying coffin Part II” – read it!
    • 787 SPECIAL CONDITIONS 25-360-SC — IN FLIGHT FIRES
    The 787-8 composite fuselage structure must be shown to be resistant to flame propagation under
    the fire threat used to develop 14 CFR 25.856(a). If products of combustion are observed beyond the
    test heat source, they must be evaluated and found acceptable.
    § 25.856 Thermal/Acoustic insulation materials.
    (a) Thermal/acoustic insulation material installed in the fuselage must meet the flame
    propagation test requirements of part VI of Appendix F to this part, or other approved
    equivalent test requirements. “Part VI” states . . . .
    “Use this test method to evaluate the flammability and flame propagation
    characteristics of thermal/acoustic insulation when exposed to both a radiant heat
    source and a flame.” The material is placed horizontally and a ¾” inner flame cone from
    a specified propane torch is applied for 15 seconds.
    In preparing this Comment I reviewed three large aircraft in‐flight fire related (caused by) accidents,
    Saudia Flight 63 August 19, 1980 A/C landed safely – 301 died
    Air Canada Flight 297 June 2, 1993 A/C landed safely – 23 died
    SwissAir Flight 111 August 1, 2003 A/C Crashed ‐‐ 229 killed
    You can Google on these flight names and read the details!
    QUESTION TO THE FAA? How do you limit the application of a flame to any material inside
    the airplane to only 15 seconds?
    • 787 SPECIAL CONDITIONS 25-362-SC — Boeing Model 787-8
    Airplane; Crashworthiness
    The Boeing Model 7878
    must provide an equivalent level of occupant safety and survivability to that
    provided by previously certificated widebody
    transports of similar size under foreseeable survivable impact
    events for the following four criteria. In order to demonstrate an equivalent level of occupant safety and
    survivability, the applicant must demonstrate that the Model 7878
    meets the following criteria for a range
    of airplane vertical descent velocities up to 30 ft/sec.
    1. Retention of items of mass. . . . .
    2. Maintenance of acceptable acceleration and loads experienced by the occupants. . . . .
    3. Maintenance of a survivable volume. . . . .
    4. Maintenance of occupant emergency egress paths. . . .
    First Commenter: The commenter, a member of the public, provided suggestions and comments related
    to the subject of crash simulation structural analysis as it pertains to the applicant’s demonstration of
    compliance to these special conditions. This commenter agreed with the intent of the special conditions.
    However, he suggested that they be expanded or new special conditions developed to require a full
    fuselage fuel fed fire test to address possible fire, smoke, and toxicity (FST) hazards that may be
    associated with use of carbon fiber epoxy structure on the 787.
    The commenter recommended that the special conditions include a requirement for a full scale drop
    test with a forward velocity vector to simulate a condition representative of a wheels‐up landing, with the
    resultant vector sum of the vertical and longitudinal velocity components being included to assess the
    loads on the passengers and crew.
    FAA Response: We agree that fuselage post‐crash fire survivability of the 787, including FST
    hazards that may be associated with use of carbon fiber epoxy structure, is an important issue. This
    issue is outside the scope of these special conditions, however. It is being addressed in conjunction with
    the requirements for Sec. 25.856(b) relating to fuselage fire penetration protection.
    MY response to this FAA response: No person involved in the design, certification, operation or
    maintenance of Large Aircraft should disagree with the intent of Sec. 25.856(b). We do not believe,
    however, that it does protect the occupants of the aircraft from the hazards of Fire, Smoke and Toxicity.
    In a wheels up, any or all landing gears, the fuselage can split open (see media photos of recent aborted
    take‐off (DENVER) or failed “normal” landing events (Amsterdam). I agree with the following comments
    and disagree with the FAA’s response to them,
    Two commenters, representing the major airframe manufacturers in the United States and Europe, urged
    that the FAA withdraw proposed part VII of appendix F to Part 25 and propose instead a general
    requirement for fuselage fire penetration resistance. Other commenters stated that the FAA must address
    areas that currently have no insulation, or areas where insulation might be removed. Some commenters
    stated that insulation should be required as part of this rule.
    The FAA disagrees with the comments.
    I reviewed six (see last section re Special Conditions for two 727‐100 series accidents) accidents in the
    preparation of my comments:
    CAL 737500
    FLT 2440 DENVER 12202008
    – NO FATALITIES
    Firefighters were on scene quickly, as the aircraft came to rest near one of the airport’s four fire houses.
    When the firefighters arrived, most of the right side of the plane was on fire while passengers were
    climbing out of the left side, being assisted by flight attendants (there were two complete flight crews –
    12 people – on board, which may explain the lack of fatalities). The aircraft sustained severe damage. The
    fuselage was cracked just behind the wings, the number 1 engine and main landing gear were sheared off,
    and the nose gear collapsed. The fire caused overhead luggage compartments to melt onto seats.
    USAIR FLIGHT 5050 737NG – LA GUARDIA SEPTEMBER 20, 1989 2
    KILLED
    As the aircraft began its takeoff roll down runway 31 at LaGuardia, the rudder was mistakenly deflected
    16 degrees to the left. . . . . Noticing the error, the Captain assumed control and began aborting the takeoff.
    The Boeing 737 continued rolling and overran the runway, landing in the East River and breaking into
    three pieces.
    American Airlines Flight 1420 MD82
    Little
    Rock, Arkansas June 1, 1999 – 11 KILLED
    The aircraft overran the runway upon landing in Little Rock and crashed. The aircraft skidded off the far
    end of the runway at high speed and finally came to a stop on the banks of the Arkansas River. The
    aircraft broke into three pieces and ignited.
    SPANAIR FLIGHT 5022 MD82
    – MADRID AUGUST 20, 2008 152 – 154 KILLED
    The crew failed to set the flaps for take‐off . . . . The aircraft was unable to maintain adequate airspeed to
    prevent altitude loss and crashed in the vicinity of the runway, breaking into at least two parts which
    were engulfed by the subsequent explosion.
    • SPECIAL CONDITIONS 25-348 SC — Boeing Model 787-8
    Airplane; Composite Wing and Fuel Tank Novel or Unusual Design
    Features
    The 787 will incorporate a number of novel or unusual design features. Because of rapid improvements
    in airplane technology, the applicable airworthiness regulations do not contain adequate or appropriate safety
    standards for these design features. These special conditions for the 787 contain the additional safety standards
    that the Administrator considers necessary to establish a level of safety equivalent to that established by the
    existing airworthiness standards.
    The 787 will be the first large transport category airplane not built mainly with aluminum materials for
    the fuel tank structure. Instead it will use chiefly composite materials for the structural elements and skin of the
    wings and fuel tanks. Conventional airplanes with aluminum skin and structure provide a well understood level
    of safety during post-crash fires with respect to fuel tanks. This is based on service history and extensive fullscale
    fire testing. Composites may or may not have capabilities equivalent to aluminum, and current regulations
    do not provide objective performance requirements for wing and fuel tank structure with respect to post-crash
    fire safety. Use of composite structure is new and novel compared to the designs envisioned when the
    applicable regulations were written. Because of this, Boeing must present additional confirmation by test and
    analysis that the 787 provides an acceptable level of safety with respect to the performance of the wings and
    fuel tanks during an external fuel-fed fire.
    The Special Conditions (Wing fuel tanks)
    Accordingly, pursuant to the authority delegated to me by the Administrator, the following special
    conditions are issued as part of the type certification basis for the Boeing Model 787-8 airplane.
    In addition to complying with 14 CFR part 25 regulations governing the fire-safety performance of the
    fuel tanks, wings, and nacelle, the Boeing Model 787-8 must demonstrate acceptable post-crash survivability in
    the event the wings are exposed to a large fuel-fed ground fire. Boeing must demonstrate that the wing and fuel
    tank design can endure an external fuel-fed pool fire for at least 5 minutes. This shall be demonstrated for
    minimum fuel loads (not less than reserve fuel levels) and maximum fuel loads (maximum range fuel quantities),
    and other identified critical fuel loads. Considerations shall include fuel tank flammability, burn-through
    resistance, wing structural strength retention properties, and auto-ignition threats during a ground fire event
    for the required time duration.
    My Comments to the Special Conditions (Wing fuel tanks)
    I am a little confused by this Special Condition because it appears to be a “static test” – not simulating an
    aborted take off or a botched landing with resulting wing structural damage and a fuel fed fire.
    The FAA has discussed, and dismissed, eight professional comments to the proposed Special Conditions – They
    have cited one Advisory Circular – AC 20-135 – that doesn’t contain the words “fuel tanks” (it is related to
    Powerplant Installations), but it refers to fire resistant capabilities. Let’s take a moment to read them.
    a. Fireproof: The capability of a material or component to withstand, as well as or better than steel, a
    2000°F flame (±150°F) for 15 minutes minimum, while still fulfilling its design purpose. The term “fireproof,”
    when applied to materials and parts used to confine fires within designated fire zones, means that the material or
    part will perform this function under conditions likely to occur in such zones and will withstand a 2000°F flame
    (±150°F) for 15 minutes minimum.
    b. Fire Resistant: When applied to powerplant installations such as fluid carrying lines, flammable fluid
    system components, wiring, air ducts, fittings and powerplant controls, “fire resistant” means the capability of a
    material or component to perform its intended functions under the heat and other conditions likely to occur at
    the particular location and to withstand a 2000°F flame (±150°F) for 5 minutes minimum. (Example: A fire
    resistant hose which will withstand a 2000°F flame for 5 minutes.)
    The Special Conditions (Wing fuel tanks) do not require the application of 2000°F flame (±150°F) for
    either 5 or 15 minutes minimum. My research has disclosed that ACMs (Advanced Carbon Material) will ignite
    at approximately 500°F. One popular general aviation composite aircraft has been destroyed by fire resulting
    from an overheated wheel brake (approximately 8 inches in diameter and weighing less than 10 pounds).
    Imagine the heat that could be stored in a 20 inch brake weighing a hundred or so pounds – in main landing gear
    wheel wells adjacent to the wing center section fuel tanks!
    Comment 6 . . . . . FAA Response. While we agree with the commenter that these are important considerations,
    the FAA has determined that this comment is outside the scope of these special conditions because they are
    limited to performance of the wing and fuel tank structure during a post crash ground fire. The performance of
    the fuselage barrel and interiors during a fuel-fed fire is already addressed by existing regulations (reference 14
    CFR 25.853, 25.855, and 25.856 and Appendix F for current standards for airplane interior fire safety). We
    have determined that existing regulations for a fuel-fed external fire are adequate to address cabin interiors,
    including those issues suggested by the commenter, and special conditions are not warranted. In addition,
    while full scale fire tests of the wing and fuselage were considered by the FAA, we determined that
    requiring a large scale fire test could be overly prescriptive (emp. added).
    I have two comments to the use of “overly prescriptive” in this response. NASA modified a Boeing 720B (a
    light weight version of the 707) as a pilotless vehicle and crashed it on December 1, 1984 at Edwards AFB (it
    was planned that the aircraft would land wings-level and exactly on the centerline during the CID, thus allowing
    the fuselage to remain intact as the wings were sliced open by eight posts cemented into the runway. The Boeing
    720 landed askew and caused a cabin fire when burning fuel was able to enter the fuselage). (You can find the
    video on the internet – you won’t be too comfortable after viewing it).
    Prior to the Edwards flight a ground test crash of a former airliner DC-7 was carried out at Deer Valley Airport
    (north Phoenix). The aircraft was restrained and guided, and crashed into obstructions at the end of “the
    runway” at approximately 40 miles per hour. These tests were looking for solutions to low speed crashes and
    fuel fed fires.
    And now, after these earlier attempts at “real world” tests, this Special Condition appears to be nothing
    more than igniting an unspecified quantity of fuel that has spilled on the ground, perhaps near the
    aircraft?
    NONE OF THE ABOVE SPECIAL CONDITIONS RESPONDED TO THE EXPRESSED CONCERNS
    OF PERSONS SUBMITTING COMMENTS REGARDING SMOKE . . . . Keep in mind — Only 6 of the
    54 people who perished on the Manchester 737 died of direct frontal assault – burns. 48 died from smoke
    inhalation. The MD-11 crew at Peggy’s Cove lost control because of a lack of visibility caused by smoke . . . . .
    the aircraft dove into the sea at 300 knots and all of the 229 persons on board died. The 300+ deaths on the
    Saudia L-1011 and on too many more otherwise survivable accidents were caused by smoke.
    The Authorities and industry have been working since the Manchester accident to remove toxic smoke sources
    from aircraft interiors BUT these 3 Special Conditions do not even mention 14 CFR Part 25 Appendix F – Test
    V — Smoke.
    We have researched and reported – you decide. Do you want to be surrounded by materials that produce deaths
    thru Fire, Smoke and Toxicity? Advance Composite Materials used today in aircraft structures do burn –
    Google it – and do produce deadly FST!
    ˆ
    SPECIAL CONDITIONS . . . A GOOD IDEA, OR . . . . NOT SO
    GOOD.
    We handled our first Lease Return Project in 1978 . . . Three 727-22s (the short 727) . . . . Bank of America was
    the Lessor and United Airlines was the Lessee. We noted the Lease pertained to four aircraft. We asked and
    learned the fourth airplane crashed on November 11, 1965, when it made a hard landing at Salt Lake City. 43 of
    the 85 passengers were killed (four persons who had tried to escape down the aft airstairs – which wouldn’t
    open because it was in contact with the ground – survived).
    NOTE: Boeing had established the 727-100 series configuration before the initial FAA review. At “the
    meeting” the FEDs asked about the exit(s) located as far aft in the passenger area as practicable in the side of
    the fuselage at floor level? The applicant responded . . . . “We have a large mid-cabin galley door, four over
    wing exits and the tail cone airstair”. Not enuf’ responded the FEDs. The compromise was a Special Condition
    (in other words — an alternative means of compliance to Part 4b.362(b)(1), the installation of escape ropes at the
    over wing escape hatches and a 119 passenger limit. Boeing provided us with the FAA Document.)
    NOTE: 4b.362(b)(1) Type I: A rectangular opening of not less than 24 inches wide by 48inches high,
    with corner radii not greater than 4 inches, located as far aft in the passenger area as practicable in the side of
    the fuselage at floor level . . . .(c) . . . on each side of the fuselage . . .
    Three days earlier, on November 8, 1965, an American Airlines 727-23 crashed on approach to Cincinnati –
    only 1 person survived. Chasing accidents isn’t our forte – depressing—so I won’t look for other failed special
    conditions.
    CONCLUSION . . . . As I said in my earlier memo to the FAA on January 15th, the 787 does not meet the
    higher standards expected of public air transportation . . . It is evident that a large Advanced Carbon Material
    (ACM) airplane being produced today does not meet any flammability airworthiness standards, and therefore should
    not be certified as anything other than experimental – not to be operated from civil airports or over populated areas. We
    recognize that the industry has invested millions of dollars in the 787 program, but it should not continue as a civil
    aircraft program until nonflammable materials are available.
    I admit I’m looking at the bleak side of Plastic Airplanes . . . but shouldn’t someone be doing so? Oh, by the
    way, have you wondered what has been going on since the 7-8-7 rollout date . . . . that was 646 days ago (today
    is 04/14/2009). The next six to 10 months in Seattle will be interesting to watch!
    Yours in Safety,
    JIM HELMS
    NOTE: Ali Bahrami of the FAA did respond to my earlier comments in a letter I received yesterday. He is an
    advocate of the bright side of Plastic Airplanes!

    HIS LETTER FOLLOWS . . . .

    U.S. Department
    Transport Airplane Directorate 1601 Lind Avenue, S.w.
    of Transportation
    Renton, Washington 98057-3356
    Federal Aviation
    Administration
    APR 102009
    Mr. Jim Helms 1020 Yates Way, Ste 229 San Mateo, CA 94403
    Dear Mr. Helms:
    Thank you for sharing your concerns about the flammability of airplanes made from composite materials. From your correspondence, it appears you consider the incorporation of composite materials into airplane construction to be premature. Composite materials have been used on commercial airplanes for many years. On the exterior, fairings are composite, as well as certain control surfaces. Airplane interiors are also mostly composite.
    As you know, certification of aircraft designs, including composite structures, requires applicants to meet performance-based rules (Airworthiness Standards). This is true for all type certificated aircraft. The FAA has worked with industry to develop written guidance describing acceptable methods ofcompliance to design requirements for composite materials. This guidance is updated as needed to keep paee with changes in composite technology.
    Over the years, the FAA and industry have conducted extensive research and significantly upgraded cabin safety requirements to increase the likelihood ofpassenger survivability in aviation accidents. These studies indicate that, following a survivable accident, prevention of fuselage (composite or aluminum) bum-through for approximately five minutes can significantly enhance survivability. Today, as a result of this research, many aviation accidents are survivable and improvements to cabin safety have contributed to passenger survivability. It is true that composite material will eventually bum, if left long enough in a large enough fire. However, survivability is maintained because of the amount of time it takes this to occur, and the fact that evacuation will have occurred well before that. We also looked at toxicity in the context of survivability and have not observed an increase in toxicity levels when compared to current airplane designs. There is considerable infornlation further explaining these studies available at the following FAA website: http://www.fire.tc.faa.gov. and we invite you to review it.
    The FAA has been working to understand all the novel or unusual design features associated with the use of composites for many years. For example, we established several requirements for the Boeing 787 via special conditions to ensure the same high level of fire safety as would exist had the airplane been made from metal. These included
    2
    post-crash requirements, as well as in-flight fire safety, and required extensive testing. That testing showed the 787-style composite fuselage maintains some structural integrity at a point where an aluminum fuselage melts, offering better protection to the passengers. Bum-through tests likewise show that these composites are superior to aluminum in terms oftheir resistance to fire penetration.
    While the concerns raised regarding fire fighting and potential environmental ramifications of composite airframes are not related to the safety ofthe airplane, we share your interest in these issues. However, we have thus far not seen any unusual behavior that warrants overall changes to the current procedures. The FAA is working with the Air Force on future studies to assess these and other post-crash fire topics. FAA researchers have also met with the Air Force and specifically discussed the B-2 accident noted in your letter in order to better understand its relationship to issues we deal with. Any FAA reports that may result from these collaborative efforts will be made available to the public.
    Sin~ert
    .rn’
    Ali Bahrami Manager, Transport Airplane Directorate Aircraft Certification Service

  10. MAY 5th RESPONSE TO ALI BAHRAMI

    Thank you for your letter of April 10th. My simplest response addresses two points – Airworthiness Standards and the historical use of Composites on transport aircraft.

    We have been using Summit Aviation’s Computerized Federal Aviation documents since its introduction in the early 1990s. I have searched the latest version, 14 CFR Part 25 — Amdt. 25-127, 73 FR 63867, October 28, 2008, effective November 28, 2008, and do not find the word COMPOSITE mentioned. I assume that anything made of COMPOSITE MATERIAL must meet all the requirements of Part 25 including Subpart D – Design and Construction.

    As mentioned in my earlier letter to you, I don’t believe the current CFRP – ACM materials meet the flammability requirements of Appendix F – or the basic definition of Fire resistant in 14 CFR Part 1, or § 25.867 Fire protection: other components. (a) Surfaces to the rear of the nacelles, within one nacelle diameter of the nacelle centerline, must be at least fire resistant.

    At your encouragement I searched for the Industry developed written guidance describing acceptable methods of compliance to design requirements for composite materials. This guidance is updated as needed to keep pace with changes in composite technology.

    I started reading and soon came across a document that came close to sharing my opinion. It was A Fireproof Future? (Science News , Jan 16, 1999 by Corinna Wu . . . . Plastics that don’t burn could stop a fire in its tracks)
    Right now, no commercially available materials, except for metals, are sufficiently flame resistant, says Richard E. Lyon, Ph. D, a polymer scientist and manager of the fire research program at the FAA’s William J. Hughes Technical Center at the Atlantic City International Airport in New Jersey.
    14 CFR Part 1§ 1.1 — Flame resistant means not susceptible to combustion to the point of propagating a flame, beyond safe limits, after the ignition source is removed. [As a flame is an element of a fire, I have related Richard’s use of flame as relevant.]

    I found many references to polymer material being fuel for a fire. We estimate the proposed 787 airframe will have 65,000 pounds of polymer material – or fuel for a fire.

    Re historical use of composites in large aircraft. We have been working with Boeing civil aircraft since 1955 and are familiar with Boeing’s use of composites in fairings, flight control surfaces and interior furnishings. We are also familiar with your and Richard’s efforts to remove CFRP-EPOXY materials from cabin materials.

    We will, from time-to-time, continue to object to CFRP – ACMs as acceptable materials for transport category aircraft, but we are ready to move on to new fields such as lightning strike protection, improperly selected and installed fasteners and possible delaminations caused by the replacement process , improper use of metal elements in the wing center section ribs – overheating of brakes causing wheel well fires, aft fuselage burning as the fuselage drags on the runway in takeoff Vmu tests, and a host of other challenges in the first certification of a plastic airliner.

    Yours in Safety,

    JIM HELMS
    650-931-4326
    210-473-5266(c)

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