Prebennorholm From Denmark, joined Mar 2000, 6019 posts, RR: 55 Reply 1, posted (10 years 4 months 2 weeks 6 days 18 hours ago) and read 1728 times:
No, I don't think that the Concorde will last that long.
The Concorde is a civil plane operated according to civil certification.
I read something like the following in a book about the Concorde some years back:
1. Part of the certification program was running a static fatigue test rig. It was operated simultaneously with ordinary service entry, but of course its "flight time" should always run far ahead of the real planes.
2. When the whole program was finally ended some 20 years ago, and the final four production planes were "donated" to BA and AF, then part of the deal was that the costly operation of the static test rig was discontinued immediately.
3. This puts effectively a lifespan limit on the Concorde frames since they will only be allowed to fly a certain percentage of the simulated flight time accummulated by the test rig when it was closed down 20 years ago.
4. If I remember well, then the Concordes were estimated to run out of time around 2010 or 2015. It may be prolonged somewhat by the temporary grounding and later less intensive utilisation following the Paris disaster. But I would be surprised to see a "legally airworthy" Concorde after 2020.
The B-52 is a different animal operated to military rules. When something cracks, then it can be exchanged and maybe improved, and life goes on and on and on. That way, if money and the will is there, then such a plane can in principle last forever. On the other hand we can all hope that peace suddenly breaks out so all B-52s and other military planes can be scrapped next year. But that hope is probably somewhat optimistic.
Regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs, Preben Norholm
Ikarus From United Kingdom, joined Jan 2001, 3524 posts, RR: 2 Reply 3, posted (10 years 4 months 2 weeks 6 days 17 hours ago) and read 1701 times:
Prebennorholm: Just a question, it is my understanding that these days, there are no longer manufacturer-owned airframes purely for fatigue testing. For example, I remember reading that all B777 prototypes were aircraft sold to airlines (and similarly for the A340-600 etc.). So essentially, fatigue is now dealt with by computerized predictions and regular checks. Wouldn't that also enable older designs to be recertified, provided someone could compute the "critical crack length" (i.e. the crack length where something snaps off) for all components, and the necessary check intervals?
Either way, I urgently need to devise a "get rich quick" scheme, 2010 is not that far away...... anyone have any bright ideas about Fort Knox?
GDB From United Kingdom, joined May 2001, 12715 posts, RR: 80 Reply 4, posted (10 years 4 months 2 weeks 6 days 16 hours ago) and read 1706 times:
Concorde is currently to run to 8500 Reference Flights, originally it was 6700 RFs
A RF is a flight of over 170 tonnes T.O.W. Most services in other words. Less than 120 Tonnes is half a RF, such as training detail flights etc.
The extension to 8500 came about as a result of the excellent condition of the airframes found during Major checks in the 1990's.
The upgrade is known as the Life Extension Programme, involving some (though surprisingly few as it turned out) airframe modifications, such as the strengthening of the crown area above the fuselage.
The static test airframes were shut down in 1985, after achieving 20,000 supersonic flight cycles.
So the life extension is very conservative.
An extension to 10,000 RFs has been mooted.
But it is not just about RFs, maintenance costs, spares availability, and most of all, the profitability of the aircraft will be deciding factors in all probability.
At current usage, and taking account of time on the ground in 2000/2001 means we are looking at around late 2007/early 2008 when the oldest BA aircraft reaches 8500 RFs.
But an increase in flying would be accompanied by OAB's return to service, offsetting the increase somewhat.
But forget any major charter programme.
The question is, will the airlines commit to a 10000 RF extension?
While there are no obvious technical issues to prevent that as yet, I have to say, sadly, that BA Engineering no longer seem to have the commitment to do so, it will be a BA Board decision, if the Board say yes, then Engineering will have to reverse what has been happening in Concorde these past few months. Not easy, people certified on the aircraft are thin on the ground, block retirement issues are also looming large.
AF will also be a deciding factor too, to carry out the next series of Major checks, as part of the Life Extension, close co-operation will be needed, mainly in manufacturer and spares support, which has never been cheap, to put it mildly. There has been encouraging signs there.
AF aircraft have much lower hours.
It is all do-able, given the will. Currently the will appears to be lacking, however all parts of the airline are under extreme pressure to reduce costs, the fact that we are living in unusually difficult times for the industry must be taken into account, which is hard to do at the sharp end.
Retiring Concorde will be a very public decision, so not just up to BA Engineering, but they have the most significant input, Marketing have a large voice too.
After all the technical issues, whether Concorde is making money or not will be uppermost, despite the difficult airline conditions things look good there, also whether this could be maintained in the future with a further Re-Life project.
Ha763 From United States of America, joined Jan 2003, 3492 posts, RR: 6 Reply 5, posted (10 years 4 months 2 weeks 6 days 9 hours ago) and read 1660 times:
Actually, I believe there was one 777 that was used for stress testing. There is a Discovery Channel documentary about the development of the 777. In one part it showed a 777 in a rig that shook it extensively. In the final test, Boeing stressed the wings until they broke off.
Ha763 From United States of America, joined Jan 2003, 3492 posts, RR: 6 Reply 8, posted (10 years 4 months 2 weeks 4 days 10 hours ago) and read 1564 times:
The 777 Boeing used was wired up with hundreds of sensors and which I believe measured the stress the a/c while it was being shook. I don't remember how long the test was, but I believe it was supposed to be equivalent to the amount of stress the airframe would encounter over the expected in-service lifetime.
Only after Boeing tested the whole airframe, they stressed the wings to destruction. It was rather spectacular seeing the wings still attached to the rest of the airframe while bent upwards more than 20 feet.