Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
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Areas of inquiry in Lion Air crash
Oct. 29, 2018, (c) Leeham News: A three month old Boeing 737-8 MAX crashed into the sea yesterday.
There are scant clues.
A technical fault was reported the day before the flight, which was unspecified in the news reports LNC has seen. It was said to have been corrected.
Flight tracking showed a rapid descent into the water. One news story reported the pilot radioed he wanted to return due to something, but this is vague and unconfirmed.
It is far too early to speculate what happened to the airplane. There is just too much we don’t know, other than FlightTracker showed what appeared to be a rapid descent into the water.
Here’s what investigations will consider—all as a matter of the normal course of any investigation. This is not listed in priority.
Areas of investigation
- Crew proficiency, training, operation of the aircraft, health, impairments (if any).
- Was there any unusual cockpit activity (ie, cockpit intrusion, fighting, pilot suicide, hijacking, etc.).
- Terrorism, such as killing the pilots, bombing, sabotage.
- Weather influence.
- Mechanical condition of the airplane (generally and the previous day’s technical issue). Even though the airplane was brand new, the mechanical condition and history of the plane.
- Were there any faults in the construction of the airplane or engines?
- Did the delivery delay of the engines that Boeing encountered since June, with the subsequent open air storage of the airplane, play any role? Was this airplane among those involved?
- Lion Air’s safety history and maintenance practices.
All this is standard.
There is unconfirmed reports that the fault the previous day was related to unreliable airspeed data at the captains instruments while the FO instrument indicated reliable air speed data. There is also some that claim they can see the same patterns of unstable (faulty?) air speed data on the Flight Radar ADS-B plots for the flight the previous day as well as the accident flight.
A brand new aircraft, if it has to go down soon after airborne, has to have some serious defects or something that made the crew follow a wrong instrument. The previous sector this aircraft reported altitude and speed indication problems. Some rectification was done. Did that error from previous flight become worse or did that airspeed error induce a more serious mistake from pilot? As it was the first flight of the day, did they forget to remove the pitot probe covers? Questions remain. We need more data.
This is from:
https://www.thesun.co.uk/news/worldnews/7605999/indonesian-plane-crash-lion-air-aircraft-crashed-take-off-jakarta/#
There is a chart of ADS-B data embedded in the article linked above. Could the brief but sharp increase in vertical speed, followed by the rapid decrease in vertical speed, indicate a nose-up followed by a stall?
I noticed that too. overall that plane went from 5k feet to 0 in 17 seconds, 11 seconds from that vertical speed transient to impact (which was in the vicinity of 4000 feet by the trace). that’s about 250 mph vertical speed….
both point to either a major mechanical/structural failure or pilot action.
Wow, glad you narrowed it down to the only two possibilities…..mechanical failure or human error.
You should be on the investigation team
Or a possible error in the instrumentation?
What we need to do is wait for information.
In the meantime, we could resort to some tried and tested journalism.
The pilot died a hero avoiding a school/hospital.
This dosnt happen to Airbus.
The words terror and plunged.
The pilot was inexperienced.
Someone else flew instead of me
Was it a terrorist?We don’t know.
Any other suggestions for air crash bingo?
Be sure to use ‘ill fated’ or ‘doomed’ near the start of newspaper or TV report, because that’s a fresh and insightful way of describing every crash ever.
I assume the tailplane issues of some years ago could not re-emerge?
Would this new Max plane have any cockpit / instrument improvements to allow pilots to have better situational awareness during a pitot tube fault?
Hello cj,
Regarding: “Would this new Max plane have any cockpit / instrument improvements to allow pilots to have better situational awareness during a pitot tube fault?”
Maintaining an accurate picture of flight path with malfunctioning instruments could well be very challenging if you are in the clouds or at night away from city lights, depending on the exact scenario; however, in clear weather in daylight hours there is a simple and reliable way to maintain situational awareness and control no matter how messed up your fancy computer screens are: if your cockpit has windows (the MAX cockpit does have windows), and what the fancy computer screens are showing doesn’t match what you are seeing out the windows, then ignore the fancy computer screen artificial horizons and fly by reference to the real world horizon outside your windows. See the video at the link below for a demonstration, bad airspeed indicator, no fancy computer autoland, clear day, the pilot ignores the nonsense coming from his airspeed indicator and lands safely by the method of looking out the window. Whether this has any relevance to any malfunction that may or may not have occurred before the Lion Air crash, I don’t claim to know.
https://www.youtube.com/watch?v=327PDKFUoR0
From a 2003 Boeing Aero Magazine article on erroneous flight instruments.
“Flight crews should be aware of the approximate airplane attitude and thrust for each flight maneuver. Knowledge of airplane pitch attitudes for given flight conditions and configurations can help identify potential airspeed anomalies before they degrade to an unsafe condition.”
http://www.boeing.com/commercial/aeromagazine/aero_23/EFII_story.html
Airspeed Indicator Failure in a 737 Classic Simulator.
https://www.youtube.com/watch?v=GhoTVJmOmMw
Interesting comments that passengers had on their flight on this airplane the day before it crashed. They said things like: The plane appeared under powered; They were going up and down a lot; And that overall people were very uneasy and some were sick to their stomachs.
I don’t know if Scott has heard any rumours, but in the list of potential problems one is unusual and no one else has mentioned it. I believe that there were some FADEC issues with the LEAP A.
LEAP A on a Boeing?
Obviously not
Another theory – this one pertaining to a rear elevator issue. I guess there will continue to be a plethora of these, but until they can examine the wreckage and flight data, it’s all just guess work.
https://www.perthnow.com.au/news/disaster-and-emergency/australian-engineers-theory-on-what-caused-the-lion-air-crash-ng-b881007399z
There were issues with the 737 a few years back involving uncommanded control issues with the tail plane. I assume that issue was resolved following a couple of major accidents.
Hope it is not anything similar.
The sudden descent and sam’s comment above about the previous day’s flight, made me think of Alaska 261 and the possibility of issues with the tail plane
The jackscrew of that well-used MD-83 had been improperly maintained, resulting in near-complete loss of authority of the pitch axis. I doubt this nearly-new 738MAX suffered from that specific root cause of this event.
At issue is that the the limited data supports a number of theories.
Loss of pitot mis handled to loss of orientation (not flying the instruments)
I don’t know what the weather was nor what the daylight situation is that time of the year in Indonesia.
The 737 Rudder issue was resolved. Boeing fought it tooth and nail but since the correction not another instance.
>Boeing fought it tooth and nail
No way they would ever publicly admit to a fault even if they privately agreed with the analysis and need for a change.
BBC Flight Radar Charts-
The top chart appears to show all the symptoms of an aircraft that is loaded tail heavy.
Weren’t there some changes to the control system with the MAX?
I believe they went with electronic control of the spoilers.
Having followed the bizarre King Air crash in Australia, you just never know. None of the usual suspect in that case (control locks left in I believe)
This can serve as a hint to what we do not know “Indonesia orders removal of Lion Air technical director after crash —state media” They also removed technical stuff who took care of the airplane .
Such hints are really no help.
Wrong repair procedure and certification that its been effective apply to all issues.
They have found the wreak and recovered FDR
The hints point to Pitot and or altimeter issues.
While the backup altimeter would be part of the static system, the radar altimeter would be used at lower levels (so I think)
It takes a disciplined crew to deal with speed issues, AF447 did not and while they had a lot of experience, clearly discipline and understanding of the aircraft was not there.