Leeham News and Analysis
There's more to real news than a news release.
Bjorn’s Corner: Aircraft deterioration
By Bjorn Fehrm
27 November 2015, ©. Leeham Co: In an article yesterday, we looked at the economics of acquiring used aircraft for long range operations. We compare getting a second hand Boeing 777-200ER or Airbus A340-300 to operate as a long range complement to an existing network or to start a charter operation to destinations further away than previously possible.
The low fuel cost has made longer range destinations economical for a number of business models and the low capital cost and good conditions of these aircraft open new opportunities.
One of the things that must be considered in such analysis is the deterioration of the aircraft’s components. This will affect the aircraft’s performance in a marked way. In fact, an aircraft only has its factory advertised performance once in its life-time: at delivery.
Certain types of deterioration can be reset to zero by maintenance actions; others will not be reset completely by a visit to the maintenance shop. Let’s go through the different forms of deterioration that one normally caters for in performance calculations and how one go about to restore the aircraft’s operation as much as possible with scheduled maintenance.
Bjorn’s Corner: Production rates
By Bjorn Fehrm
20 November 2015, ©. Leeham Co: Emirates Airline CEO, Tim Clark, is quoted as having said “it takes them forever to get this thing up.” He was talking about the Airbus A350 production rate and his reasons for delaying Emirates’ decision on what to buy for the airlines medium range needs. Clark said Emirates wants more aircraft in operational use before they can evaluate the operational characteristics of the A350.
Emirates want to see at least 20 aircraft in operation and right now it is about seven to nine that fly every day. Actual deliveries stand at 10 with one month to go before the first anniversary when deliveries started (the first A350-900 was delivered to Qatar Airways on the 22 December 2014).
Looking at how many aircraft that are actually flying, one can agree with him. It seems actual production rate is more like one per month rather than the three to four a month that Airbus talked about at the first delivery ceremony.
So why is this? Is the production of A350 therefore in serious trouble? What is taking them so long? Has Emirates pointed to a weak part of the A350 program?
Bjorn’s Corner: MRJ90 first flight
By Bjorn Fehrm
13 November 2015, ©. Leeham Co: Mitsubishi flew their MRJ for the first time this week. I could have added “finally” because it is two years late compared to the original time plan. But who cares when the aircraft is finally ready to fly and everything goes well? (Well, the customers do, actually.)
It was a big moment for Japan, a nation with a sizable aeronautical industry. Japan has been a major partner to Boeing in their larger airplane programs over the 757/767 to the 777 and 787. For the Dreamliner, they even designed and made the hottest item, the high-tech Carbon Fibre Reinforced Plastic (CFRP) wing.
Despite having such a capable aeronautical industry, Japan has not built an own civil aircraft since it closed the production line for the YS-11 twin engined turboprop in 1973. Since then it has acted as sub-supplier and has worked on certain military programs like the Mitsubishi F-2 fighter, based on the Lockheed Martin F16.
The Mitsubishi corporation flew the MRJ90 for the first time Wednesday from the Nagoya Airport in Japan (screenshot from video from Mitsubishi). Most of the flight testing will be done in Moses Lake (WA), USA, where four test airplanes will be based.
Moses Lake is blessed with open skies, little air traffic, a long runway and good weather. It has a long history of flight testing, serving as a test-base for Japan Air Lines 747 pilot training for decades. Boeing also uses Moses Lake for flight testing.
We analyzed the MRJ90 and its main competitor the Embraer E175 in a subscriber article the 25th of January. We will revisit the main characteristics and then comment on what could be seen from the first flight. Read more
Bjorn’s Corner: Aircraft systems, the real nuts to crack
By Bjorn Fehrm
06 November 2015, ©. Leeham Co: COMAC’s C919 was rolled out in the week. We got to see a new shiny aircraft which looked ready to fly. The nicely curved fuselage and wings were immaculate, the paint was shiny and the CFM LEAP-1C engines were ready to go.
Yet many ask, when will it fly for the first time? It used to be that when the airframe was finished and the engines ran reliably it was time to fly. No longer! Today the most challenging part of an aircraft program is the integration of all the complex systems which hide under the skin. This is what kept the Bombardier CSeries on ground longer than it should and the Boeing 787 and Airbus A380 had the same flu (the latter also had to short wires).
It is the part of the aircraft which takes longest to get to work reliably. The A380 is known for its long period of nuisance warnings from the complex avionics system after entry into service and the reliability work for the 787 has to a large extent been one of software tuning of its system side.
As the system function of modern aircraft has grown more complex the whole architecture of how it was built had to be changed. Here’s how.
Bjorn’s Corner: Aircraft programs
By Bjorn Fehrm
30 October 2015, ©. Leeham Co: There has been dramatic news this week around Bombardier’s (BBD) CSeries program. I wrote a subscribers article about what to expect in terms of the cash flow problem that the BBD management has been wrestling with. The announcements yesterday and the following earnings call confirmed the financial modelling I did with our aircraft modelling tool.
Having watched experienced Wall Street analysts being hard pressed to understand what has happened with the CSeries, I thought I could use this week’s corner to explain the overall economical flow of an aircraft program like the CSeries (there will be details in a follow up subscriber article). I will also put it in context with how it affects a company like BBD and what one must think about when it comes to timing of such projects.
To give the timing aspect more colour, I will also compare with Embraer and their E-Jet E2 project and Boeing’s 787 program. The three programs are very different and they demonstrate in an illustrative way the challenges of making a new civil airliner and that one must adapt the project to the company’s position and its strength and weaknesses.
Bjorn’s Corner: Increasing an aircraft’s range, further considerations
By Bjorn Fehrm
23 October 2015, ©. Leeham Co: In last week’s Corner, we went through how Airbus can offer an Ultra Long Haul (ULH) aircraft to Singapore Airlines by increasing the Maximum Take-Off Weight of its A350-900, increasing the tankage and lower the payload. There are a couple of other considerations when extending the range of an aircraft that we did not touch upon. For completeness, we go through them here.
When increasing the allowed weights (really, masses) of a certified airliner, there are a few things that need to be re-evaluated and perhaps modified. First of all, the airframe needs to withstand the higher loads caused by the higher weights. Secondly, the aircraft’s field performance will be affected by higher weights. Required take-off field length must stay within usable limits, as must landing performance.
If the increase in flying weights are significant, it will also require a check on what happens to the aircraft’s flight profile when fully loaded. A heavier aircraft will cruise at lower flight levels and the One Engine Inoperative (OEI) service ceiling will diminish.
We now go through these additional areas and evaluate their impact on overall aircraft performance in general and on an A350-900ULR in particular.
Bjorn’s Corner: Increasing an aircraft’s range
By Bjorn Fehrm
16 October 2015, ©. Leeham Co: Airbus announced this week how it made an Ultra Long Haul (ULH) aircraft out of the long haul A350-900. The resulting A350-900ULR (Ultra Long Range) enables Singapore Airlines to reopen the famous direct “Flight 21” to New York.
But Singapore’s press release also talks about US West coast destinations, the first being Los Angles. They released this picture:
Reading the many comments around how an aircraft like A350-900 can reach such longer range, it can be worth going through the basics on how different parameters affect range and what Airbus or any other OEM has to consider when they want to increase the range of an existing aircraft.
We will do that from a slightly different angle than normal. We will show how a pilot would think about how he can get an aircraft with more range. Pilots reason in a different way to design engineers. They are better served by thinking on the aircraft’s range performance as endurance, meaning how many hours can we stay aloft. This works better when one plans with the prevailing weather on the route.
We will now take it step-by-step and explain which parameters matters for the pilot and which do not and how he gets his ULH aircraft. Read more
Bjorn’s Corner: Engine rubbing
09 October 2015, ©. Leeham Co: Last week an Airbus A320neo prototype with Pratt & Whitney’s (PW) GTF had a problem while testing hot and high conditions at Al-Ain airport in Abu Dhabi. The engine suffered a rubbing problem and PW and Airbus decided to replace the engine before returning the A320neo to Toulouse.
I had the opportunity to discuss what happened with PW people at ISTAT this week and decided it makes for a good follow up to our two other engine Corners to write about what happened and how serious it was.
The problem was compressor blades rubbing against the compressors stator wall. PW knew that this engine individual could have that problem. They saw when assembling the engine it was a bit tight in the compressor area. PW said they told Airbus there was a risk with this particular unit, and sure enough, there was rubbing to be seen when they boroscope checked the engine after the test.
Here what it was all about and what to do about it. Read more
Bjorn’s Corner: Engine ratings
By Bjorn Fehrm
02 October 2015, ©. Leeham Co: After the article about the role of bypass ratio on a turbofan’s efficiency, we now look at other aspects of civil turbofan engines that are worth some light. It’s about how the engine OEMs create different versions of the same engine to cater for different aircraft variants.
The aircraft OEMs create different size variants from the same base model of aircraft by means of stretches. There is no better example of that than the Boeing 737. Over the years it has had more than 10 major versions. For the present in-service series, 737NG, there is three official variants, from the -700 to the -900ER. Originally it also had a smaller -600 variant.
These require engines from 20klbf to 27klbf. How this is achieved and what it means for engine characteristics and reliability is the focus of today’s Corner. We will also compare it to a typical long range engine, the Rolls-Royce Trent 1000/7000, which powers the Boeing 787 and Airbus A330neo.
Bjorn’s Corner: USAF Tanker program
By Bjorn Fehrm
25 September 2015, ©. Leeham Co: When Scott Hamilton asked me to give my view on his article “Pontifications: Duelling refuelling tankers” I accepted. I was not involved in the project and was only following it casually over the years.
I will also not give my view on what would have been the most suitable tanker for the US Air Force. I simply don’t have the relevant military competence for that, having never operated my fighters with aerial tanking nor been in an aerial tanker aircraft.
Where I have relevant competence is in writing military specifications for important aircraft procurements and the excerpts I have seen from the tanker RFQ on key specification points don’t impress. Let me explain.