Can you do a loop-the-loop in a passenger jet?

We put this firstly to Disk Schleh, of Boeing Commercial Airplanes in Seattle, Washington:

Well a large passenger jet such as the Boeing 747 or almost, almost any large passenger jetliner was not designed nor was it tested, nor was it certified to perform aerobatic manoeuvres like a loop-the-loop or a barrel roll.

Certainly the wings of the airplane would be put under quite a bit of stress and some of the tail structure and so forth, doesn't mean it couldn't do it but they were not designed that way and they were certainly not certified with that in mind. In the early days of the jetliners when the jetliner was being developed at the Boeing company in the 1950s there was a prototype called the 367-80, that was the 707 prototype and the original test pilot on that airplane was Tex Johnston and one day he was asked to fly the aeroplane over a major event here in Seattle which was called the Hydroplane Races, so he did in fact fly the aeroplane at a fairly low altitude over the crowd but then he decided to really impress the crowd so he did a barrel roll with that airplane, much to the surprise of the Boeing officials who were watching from down below.

But he felt that it was a good demonstration of the aeroplane's capability but he was strongly reminded never to do that again and indeed, as far as I know, it has not been done again at least certainly not as part of our test operation here at Boeing.

We then asked Peter Merton, Resident Research Officer at the Imperial War Museum at Duxford. The simple answer is frankly, no. The critical points about, well not just modern passenger jet airliners but airliners built in the past during the 20s and 30s coming forward in time is that they are designed to be load carriers. So they are designed to withstand the quite severe adverse weather conditions, to be able to carry passengers and cargo in safety and especially now-a-days of course with the long-range jets to carry a lot of fuel.

So they are perfectly capable of some quite violent manoeuvres in terms of things like steep turns and I have seen them being flown with a very graceful positional flying, doing quite steep dives and climbs but not of course with passengers or cargo on board. This is the big difference that they are designed to be strong and robust and particularly to have a good survivability factor in case of an accident or a crash landing whereas the purpose designed aerobatic aircraft or even other aircraft types like fighter aircraft, can cope with the stresses and that is the critical difference really.