The Chinese "Threat"

At the Zhuhai Airshow COMAC presented first customers for their C919, aimed to be a competitor to the A320 and B737 narrowbody families.
COMAC said that there are now “up to 100 orders” – a closer look shows that 50 of these orders are firm orders the rest are options.
The four big airlines in China – Air China, China Eastern, China Southern and Hainan Airlines – all ordered the C919. The first three all ordered “up to 20”, probably meaning that 10 for each airline are firm orders and 10 are options.
GECAS is another launch customer – for 5 firm orders and another 5 options. This is not a big surprise, as GECAS is also a customer for the much-delayed ARJ21-700 and GE delivers the engines for both aircraft (as part of the CFM consortium in the case of the C919).
The last launch customer is CDB (China Development Bank) – also not a big surprise, as CDB wants to play a big role in aircraft leasing in the future and signed MoU’s with all civil aircraft manufacturers recently. An anticipated order for the Bombardier CSeries is still in the pipeline and will most probably not being made public during the Zhuhai Airshow, as Scott Hamilton assumed recently.
So the C919 got their first customers – fine! But do we see a threat for Airbus and Boeing here? Not really for the next 10-15 years to come, I would say. Let’s have a look at the numbers for outstanding firm orders from the Chinese airlines that now ordered the C919.


Air China

China Eastern
China Southern




These are the numbers as in the Airbus O&D table from October 31, 2010.
We have to add the order the 50 A320 aircraft which was signed early November.
So the total is 181 open orders.


Air China


China Southern



Additionally, there are 46 open orders from other Chinese airlines for the B737 family for a total of 151 open orders.

This is a total of 332 open orders for Airbus and Boeing narrowbodies.

Let’s have a look at the actual aircraft and the (small set of) date given to the media by COMAC at the Airshow (Flightglobals headline was “Comac releases C919 specifications”, which was a little bit exaggerated) and compare it to the A320.

Cabin width

Efficiency is driven largely by two values: aircraft (empty) weight and engine SFC. Another important factor Is the wing efficiency, expressed in L/D (lift-to-drag ratio).
The thrust needed to power the aircraft in level flight is mass*(L/D).
From press releases it is known that the LEAP-X1C for the C919 is designed for a thrust of 30klbf. The 1.3m shorter A320 has a thrust rating of 27klbf, the engines on the 5.6m longer A321 produce 33klbf of thrust at takeoff.
Weight is not given by COMAC, but the span gives a good indication of the weight. Assumed that the aspect ratio of the C919 wing is not that different from a A320 or B737 wing, the wing area is at least the same as the wing of A320. Wing loading at takeoff (takeoff mass/wing area) is - together with the takeoff thrust – the driving factor for the takeoff length. The C919 is designed with hot-and-high airports in Western China in mind, so wing loading should not be far beyond the A320.
L/D could of course be a little bit better, as the A320 wing design is well over twenty years old.
Given all that we can preclude that the C919 won’t have a large weight advantage against the A320. The main driver for efficiency will be the engine. No doubt that the LEAP-X1C will be far better in SFC than the V2500 and the CFM56-5B on the A320. But what if Airbus does the –NEO? And what if the LEAP-X1C is not the “real” LEAP, as discussed here and elsewhere?
Conclusion: for me, the C919 is not a big deal for the next ten to fifteen years – at least technically. If China decides one day that chinese airlines have to buy nothing but Chinese, then it’s a different story – and confined to the Chinese market and close allies.
By then the Chinese aircraft market could very well cool down, as high speed rail eats into air travel wherever a rail line opens.

There is a good artice on the Aviation Week Website detailing the C919 orders. It's a little bit different than originally reported by Flight International...


EASA Directive for Trent 900

The EASA found an oil fire in the HP/IP turbine area to be the cause of the uncontained failure in the #2 Trent 900 engine of the Qantas A380 on Nov. 4. This is an outcome that was expected by experts. The AD dated November 10, 2010 can be found here.
But why does an oil fire lead the IP turbine disk to disintegrate? Let's talk about what (likely?, maybe?) happened in detail and step by step:
  1. The buffer cavity between the HP and the IP gets contaminated with oil. Why this happened is pure speculation at the moment. It could have been a bearing that leaked, it could have been oil lines that leaked or failed or something else...
  2. During the take-off and climb phase temperatures in the cavity are rising high enough to let the oil ignite.
  3. The IP shaft gets overheated and fails.
  4. The IPT disk, now running free without the IP compressor as a brake, accelerates in milliseconds as fuel is still pumped into the combustor. The bore of the disk is designed to withstand speeds that are up to, say, 40% higher than the speed at takeoff, whereas the airfoils are designed to fail earlier, at maybe 120% speed. But the oil fire also heated up the bore, decreasing the so called overspeed burst margin.
  5. The disk burst at a speed before the airfoils fail.
So what needs RR to do to prevent such a failure to happen again?

First of all, prevent the oil leakage. Without oil leakage no fire, no shaft shear, no disk burst.
Secondly, as you probably never can eliminate the possibility of an oil leak for 100% sure, a functionality has to be build into the engine that detects a shaft shear and shuts off the fuel immediately. Without the fuel being burned and the energy put into the turbine gas path, the disk will not accelerate.

Rolls Royce said that the Trent 900 and the Trent 1000 uncontained failures are unrelated. That might be true with respect to the causes of the two incidents. But I would like to hear what Rolls Royce changed in their design philolosophy between the Trent 900 and the Trent 1000 (and the Trent XWB) to prevent such an overspeed beyond burst limit speeds in case of a shaft shear as it appears that the outcome of the different causes was the same.
To clarify, the story I pictured is my view on what might happened. I can't assure that it was like I wrote. I hope to hear the "real" story tomorrow from RR.


Boeings Dreamliner under Fire

News came late yesterday that the second prototype of the B787, ZA002, landed with a cabin full of smoke in Laredo, Texas. The aircraft was en route to Harlingen, TX for trials of the nitrogen generation system. The fire broke out in the aft electronics equipment bay, the PFD and the auto throttle failed and the ram air turbine deplyed to provide enough electricity to handle th aircraft and to land it safely.
No one was injured, all test personell exited the aircraft via emergency slides.

The 787 saga of problems continues! All what can go wrong - goes wrong! Said someone "Murphy...?

What and if this latest part of the 787 saga means something really serious for the further flight test campaign and first deliveries of the aircraft remains to be seen.
In the best case there "just" was something like a short-circuit in the test equipment. Then the fire has nothing to do with the aircraft itself and the test fleet will be back in the air soon.
But it would be a lot worse if the fire has something to do with the electrical or electronical system of the aircraft.
  • If it is the electrical system and some kind of short-circuit, the problem would be to find to exact location and cause of the problem. Also it would have to be examined if the cause lies in the software that controls the electrics.
  • If it is the electronics itself where the fire started, it could either be a short-circuit on a circuit board or overheating of the electronics. How long then changes will take, is up in the air...and so long the aircraft won't....
In every case, the alarm bells in Rockford, Ill., where the Electrical Systems Division of Hamilton Sundstrand is located, are ringing!


Rolls Royce faces technical and legal battles

What a bad time for Rolls Royce:
August 2: Uncontained Failure on a Trent 1000 in Darby
August 30: Uncontained Failure at a Qantas B747-400 powered by RB211’s
November 4: Uncontained Failure at a Qantas A380-842 powered by Trent 900’s
Not to mention the more minor problems two B747-400 had with a RB211 (apparently a contained failure) and with fuel hydraulics.

And now: Pratt sues Rolls on patent infringement regarding the Trent 900 and Trent 1000 fan blades.
Let us recall: not long ago, in August, Rolls Royce filed a lawsuit against Pratt & Whitney, claiming that P&W would infringe their patented design for swept fan blades with their fan blades on the GP7000 and the PW1000G (and others). This case is due to go before a jury in the US in the first half of 2011.
Pratt & Whitney apparently fights back now, filing also a complaint with the U.S. International Trade Commission (ITC), which could be very damaging for Rolls Royce, as if the ITC rules in Pratt’s favor, RR could get blocked to ship any more Trent 1000’s to Boeing. And if the UK courts come to the same conclusion, RR would also have a problem to ship the Trent 900 to Airbus.

But could that be Pratt’s real interest? Not only P&W and RR would be deadly enemies forever, also Airbus and Boeing would not be happy about P&W, as deliveries for the B787 and A380 to customers with Trent 900 and 1000 engines would be (further) delayed or in the worst case impossible. As a last consequence you could expect RR to go bankrupt.

So I doubt that this is what P&W is really looking for – even if Airbus goes ahead with the A320NEO and P&W developing a version of their PW1000G Geared Turbo Fan for it without Rolls Royce, the two companies will still be tied for centuries, as the V2500 will continue to be shipped until 2015 at least and aftermarket activities will continue  - say – twenty years plus.

So what could be the real goal behind the legal actions?
My guess: P&W wants RR to “cooperate” a little bit more on the narrowbody front:
RR officially states that reengining the current Boeing and Airbus narrowbodies does not make any sense. But it sounded a little bit different until RR was officially put out of the reengining game by Airbus. And as RR has no interest to participate as  a junior partner in the GTF, RR would be out of the narrowbody market at least until a clean sheet design either by Boeing or Airbus arrives. So one can imagine that RR will do everything (legal, of course) they can do to prevent the Airbus reengining by hindering and blocking P&W’s PW1000G to be one of the –NEO engines.
I do not know how the IAE contract between Pratt, RR and the other partners looks like, but maybe RR can block an engine offering for the A320NEO by P&W – or block order conversions from the V2500 to a PW1000G once the A320NEO is officially offered to costumers.

It will be interesting to see how RR will come out of these two battles:
-          the technical battle: RR has to regain confidence on the Trent 900/1000 – and maybe the XWB
-          the legal battle with P&W


Picture of ruptured disk

Sorry, but somehow I cannot edit the latest post anymore - so here is the picture of the ruptured Trent 900 engine disk:


The Qantas A380 engine failure - a disaster for Rolls Royce?

A first serious incident happened with an A380 – the first Qantas A380, registered VH-OQA, made an emergency landing in Singapore, not long after taking off from the same airport.
Pictures show that the aft part of the No.2 Trent 900 nacelle is missing. Eye witnesses from the ground said that there was a loud bang (or explosion) and trails of smoke after that.

All this points to an uncontained failure. In recent months we saw two other uncontained failures in RR engines – first a RB211, also with Qantas, but on a B747-400 and then the Trent1000 on a testbed in Derby.

If at least the Trent1000 failure and the -so far- suspected failure in the Trent 900 of the A380 are in any conjunction remains to be seen. At least it is not good publicity for Rolls Royce in a time that is not easy for the No.2 engine maker:

  • Deliveries of the Trent 900 are, due to the production problems and slow ramp-up of the A380, not in numbers that were anticipated in the business case. Any profit from this engine program is delayed by years (the same is also true for the GP7000, of course).
  • Even heavier probably , the Trent 1000 drags on profit margins. The 787 is late by almost three years – if the first delivery in mid-February will be met. According to the original ramp-up plan, there should have been around 200 B787 in service by now, maybe half of if powered by the Trent 1000. The performance inprovement programs, aimed to meat the promised fuel burn at the aircraft probably doubled development costs.
  • Development of the Trent XWB is in full swing, costing a lot of money, too.
So one could suspect that RR is running into a cash problem. Luckily there are the Trent 700, the leading engine for the A330, and the V2500 and Airbus upping deliveries for the A320. But if these two "cash cow" programmes can save RR in the long run, if there would be a main technical problem in the Trent 900/1000 (and maybe XWB), is questionable. A fundamental technical problem, a desígn fault, could end up in the grounding of the whole Trent powered A380 fleet. Qantas grounded their fleet of six A380 immediately after the incident, Singapore would be hit heavy with eleven A380 in their fleet today, Lufthansa so far took delivery of four aircraft.

It is too early to call today’s failure a disaster for Rolls Royce (and subsequently, for Qantas, Singapore Airlines, Lufthansa and, if the worst comes to the worst, Boeing and all their B787 Trent 100 customers) – but the possibility is there…

Update: meanwhile is is obvious that an uncontaines failure happened. Pictures are showing damage to the wing - Singapore Airlines effectively grounded their fleet also. Officially, all flights are just "delayed" until the engines are inspected, but a 100% inspection of the disks for such a failure would mean to take the engine apart...

Update 2:
Just found the preliminary report of the uncontained failure in the RB211-524, which happened on August 30th. It can be found here.
The key observations are (quoted from the report):

All of the turbine blades had separated from the IP turbine disk.
Blades from the three LP turbine stages were either fractured through the airfoil section or separated from the disk.
The LP stage 1 nozzle guide vanes were destroyed. The remaining LP nozzle stages were substantially damaged.
The LP turbine bearing and adjacent phonic wheel and speed probes were destroyed.
• The IP shaft was severed towards the aft end.

This picture is obviously a part of a turbine disk that fell on the island of Batam - we will soon hear if it is also the IPT disk - at least all baldes are missing.

The Trent 1000 failure also happened in the IP Turbine. If now yesterday's failure also can be tracde back to the IPT, I would be happy not to be employed in Derby...


New 787 delays?

Flightblogger today reports about possible new delivery delays of the 787 due to rework being done before delivering the aircraft to the customers.
As long as Boeing does not confirm that there is a new delay we have to talk about speculations – but so far, every time such a speculation came across there was at least some truth in it (just to sound polite…).
The article suggests that the first aircraft will still be delivered to ANA in mid February, but won’t be able to enter service without further modifications. I guess this is something the ANA management will not be happy with: they won’t take delivery of an aircraft without being able to take it with them – just makes no sense, even if we can assume that ANA will effectively get this aircraft for free.
But the exact timing of this first delivery does only have symbolic meaning anyway. (One of) the important question(s) is: when will Boeing be able to deliver the “Dreamliner” in numbers?
We would need more information about the specific problems and modifications that Boeing deals with. Jon Ostrower lists a few of them:
·        a flight deck window popping sound
·        cabin condensation issues
·        reworking passenger doors
·        changes to the Trent 1000 engine (Package B)

The pooping sound of the window should not be a big issue – proper insulation should care for that.
Cabin condensation seems to point to a problem with the air conditioning. That could mean everything: if they are lucky they just have to adjust the software – if they are unlucky, the humidifier are too small and have to be redesigned.
Reworking the passenger doors should not be the thing that holds up deliveries for months – reworking the stabilizers was probably more complicated, but is not a new problem and led to the latest (official) delivery slip – among the problems with the Trent engines.
So from what is being mentioned, a new slippage for months would not be explainable. The question is: which problems are not mentioned here?
I guess Boeing will soon have to give answers to the Flightblogger report – they should tell the public the whole story, they already lost too much credibility to just release the obvious…