Discussion
Okay chaps few questions here, Im not exactly that clued up on planes (other than accepting they are the devils work given they are that heavy and can fly (much like big boats that dont sink)).
So, I was watching Quest's Mighty Planes last night and it was following the USAF C-5M Super Galaxy's taking a consignments to Afghanistan, as part of that they went through the C5 upgrade programme where by the C5's were essentially taken back to a carcass and upgraded to Galaxy status with the only structural work being carried out being additional strengthening on the wings with the new more powerful engines going in(so far so good).
However, (and never believe everything you see on TV), they made mention that the C5's entered service 40 years ago (which a quick google search confirms C-5a 1968-1973 & C-5B 1985-1989), now the intimation was that these planes being upgraded were 40years old and that once upgraded they would be good to go for another 30 years service.
Now I did a bit of googling this morning and as I thought aircraft lifespan is determinable by the amount of pressurizations etc. they go through which made it seem a bit far fetched that a plane could still be in active service 70 after being built. Is this infact the case? or were the programme facts a bit skewed and it was the later 1985-1989 built planes that were being upgraded? or are the USAF planes the equivalent of a low mileage car?
So, I was watching Quest's Mighty Planes last night and it was following the USAF C-5M Super Galaxy's taking a consignments to Afghanistan, as part of that they went through the C5 upgrade programme where by the C5's were essentially taken back to a carcass and upgraded to Galaxy status with the only structural work being carried out being additional strengthening on the wings with the new more powerful engines going in(so far so good).
However, (and never believe everything you see on TV), they made mention that the C5's entered service 40 years ago (which a quick google search confirms C-5a 1968-1973 & C-5B 1985-1989), now the intimation was that these planes being upgraded were 40years old and that once upgraded they would be good to go for another 30 years service.
Now I did a bit of googling this morning and as I thought aircraft lifespan is determinable by the amount of pressurizations etc. they go through which made it seem a bit far fetched that a plane could still be in active service 70 after being built. Is this infact the case? or were the programme facts a bit skewed and it was the later 1985-1989 built planes that were being upgraded? or are the USAF planes the equivalent of a low mileage car?
2DDav said:
aircraft lifespan is determinable by the amount of pressurizations etc.
Re this bit..Its even more complicated than that is now done by individual manoeuvres, each flight of the 52's is recorded and a cumulative score given for the flight. Those flights are then added up to give its possible life span/issues....
Add in the amount of training that now goes in in simulators (B2's are virtually too expensive to train in) then if your not using them the planes can last forever...
badgers_back said:
Its even more complicated than that is now done by individual manoeuvres, each flight of the 52's is recorded and a cumulative score given for the flight. Those flights are then added up to give its possible life span/issues.
Military operators have been doing that for years. For eg the RAF uses the 700 Series Forms to record anything and everything done to an a/c.Specifically, Form 725 (Flying Log and Fatigue Data Sheet) records various parameters that may be experienced in flight:
http://www.google.co.uk/url?sa=t&rct=j&q=M...
As you can see, in this particular application not only is flight time and max altitude recorded, but number of pressurisations (both above and below 4psi), number of landings (roller and braked), fuel load/burn, fatigue meter readings, as well as 'sortie profile code' which is a numerical code representing the typical types of loadings to which the a/c will have been subjected vs the flight parameters of the sortie.
These details are then recorded on a central computer database such that the Fatigue Index (FI) of each specific a/c can be monitored and husbanded.
A Lot of military aircraft also have strain gauges and fatigue meters, at opposite extremes the Tornado is covered in strain gauges and they are read and noted after each flight and the venerable Bulldog has a fatigue meter which clocks up the type of flying it does, hence they are always advertised with their fatigue meter readings as they have a finite life
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