Thread: Hole in plane

I wonder what the realistic lifespan of these Boeing 747s are. I don't know if I would be using a 17 year old vehicle for a long trip

A complex 17 year old long haul plane that flies over the ocean, carrying 300+ passengers just sounds like courting trouble.

what about all those Douglas DC-3's that are still flying all around the world?

well done to the Crew, boo hiss to the media.

Goes to show how strong the ol' tin pigeons are.....

It's not so much the age of the airframe but the number of cycles it's completed - a cycle is (for pressurised aircraft), a pressurisation and depressurisation or take off, climb, cruise, decent and landing. So you pump a heap of air into a metal tube then after a while you let it out - obviously the pressure and temperature changes in doing this will fatigue the material.

The section of fuselage where this one happened was near the wing which is generally the strongest part of the airframe - not a bad place to happen.

Aluminium will corrode and de-laminate in time but the checks performed on this type of aircraft will be detected and dealt with - it's part of the maintenance schedule. It seems an explosion of some sort has breached the pressure vessel and in turn caused the wing root fairing to fail, which is a filler to enhance aerodynamics but when they're missing it looks quite dramatic (enter media). Either way a rapid decompression is a check-listed item and a regular feature of training, so unless there's an ensuing catastrophic structural failure it's not a big drama - for the crew anyway. It's just all those movies that help everyone think they're going to die.... (media x 2).

The clowns (media x 3) also drew comparisons with well documented failures of the DC-10 which was a design fault with it's cargo door locks. At the end of the day if you keep pumping air into and out of a tin can it's gonna pop which is why all compnents have a 'life' in terms of cycles or hours (particularly the windows).

DC-3 - can't be beaten, it's too simple.


Matt

Originally Posted by tempestv8

I wonder what the realistic lifespan of these Boeing 747s are. I don't know if I would be using a 17 year old vehicle for a long trip

A complex 17 year old long haul plane that flies over the ocean, carrying 300+ passengers just sounds like courting trouble.

some of the ex ba then virgin 747-100 aircrfat i worked on several years ago were well over 100hrs on the fusealge.
the fuselage is lifed at about 25 but with extension scan go to 30-35 and thats before its sent to africa to a bit more on teh mail runs.
so long and short they work damn hard.

Age is really irrelevant on aircraft - history and maintenance are what counts. Qantas aircraft can be expected to last longer than most because of the very long average flight legs. There are probably many 747s in use a lot older than this one. For example, there are still a few 747SPs in service I believe - and it is about thirty years since the last one was built.

Consider DC3s, as suggested - last one was built in 1945, still probably dozens flying (but there are special considerations - they were built far stronger than necessary, and the alloy used is virtually immune to fatigue). or consider the B52 bomber - it has now been in service for over fifty years, and is expected to continue in service until at least 2040. Aircraft, because they are legally required to be properly maintained, are virtually never retired simply because of their age. What usually happens is that some key component reaches its service life limit, and it is cheaper to replace the whole aircraft rather than that item (for example, a wing spar). Or a replacement aircraft becomes available that makes more economic sense, although what happens then, is the selling price of the old plane reflects this, and it becomes economic for someone else to run it because of the low capital cost. And this continues until it becomes worth more as scrap, or it becomes impossible to get parts.

Having recently driven a 21 year old car across Australia and back without any vehicle problems, I have difficulty in seeing seventeen years as particularly old. And the thing about aircraft, is that when it comes out of a 'D' inspection, it is intended to be as it came from the factory, at least as far as safety and reliability go.

John

Originally Posted by tempestv8

I wonder what the realistic lifespan of these Boeing 747s are. I don't know if I would be using a 17 year old vehicle for a long trip

A complex 17 year old long haul plane that flies over the ocean, carrying 300+ passengers just sounds like courting trouble.

I suspect the 17 year old QANTAS aircraft has had fewer cycles than a newer short haul aircraft and its airframe could be in better condition.

Originally Posted by muddymech

some of the ex ba then virgin 747-100 aircrfat i worked on several years ago were well over 100hrs on the fusealge.
the fuselage is lifed at about 25 but with extension scan go to 30-35 and thats before its sent to africa to a bit more on teh mail runs.
so long and short they work damn hard.

100 hours seems very little.