Human-Computer Interaction 3e Dix, Finlay, Abowd, Beale

online!    Spitfire or not a Spitfire?

see page 49. Design Focus: Human error and false memories

Well it did seem such a good story we told in the second edition, the Spitfire with a confusing ejector seat button ... but unfortunately not quite accurate!

... ah well, we got it right in the 3rd edition ... but all thanks to Kai-Mikael Jää-Aro of the Royal Institute of Technology, Sweden.

The information below is a lightly edited version of his emails.

The original story was about a Spitfire where a re-design of the cockpit swopped the locatiosn of firing button and ejectort seat ... well, as Kai-Mikeal explained ... the story was wrong on two counts. First NO Spitfire had an ejection seat and indeed ejection seats were very unusual in piston-engine aircraft to begin with (an exception being the SAAB J21/A21 and some test flights of Martin-Baker in a Boulton-Paul Defiant). Even opening the hood was completely manual - and it is claimed that a crowbar was added as standard cockpit equipment to let the pilot smash the hood if it had stuck due to battle damage. S.J. Paine says in "Spitfire Anatomy (part four)" in Aeroplane Monthly, February 1995, p 14:

"The canopy hood on this aircraft [the Mk XVI] had no winding gear, as was introduced on the Mk XIV, but had to be moved fore-and-aft manually."

In Peter Hearn's The Sky People - A History of Parachuting, Airlife, 1990, it says on p 90:

"In 1947 the Martin-Baker ejection seat was accepted by the RAF and the Royal Navy, ..."

Thus no British ejection seats in WW II (but there would have been, at least in jet aircraft, by the Korea War). The Luftwaffe did use them "in their faster fighters [...] but the failure rate was high". William Green's War Planes of the Third Reich, Galahad Books, 1970, confirms that at least the Do 335, He 162, He 219A-7 and He 280 had ejector seats; admittedly, none of these was used in any large numbers (only the He 219 saw operational service at all), but according to Green the He 280 has the distinction of being the first aircraft ever equipped with an ejector seat, and also the first aircraft in which it had to be used in an emergency.

Furthermore, the story is alas unlikely even for another plane as no aircraft designer would move the gun trigger away from its position on the top of the control column, it being the most important function of a fighter aircraft and has to be immediately accessible at all times (which an ejection seat does not).

So where did we get the story from. Well I (Alan here) recalled it from some conference or other and presumably garbled it completely. is ther any truth in it at all, or is it simply an urban (or academic) legend.

Happily, Kai-Mikael came to my help here and recalls several other similar stories, where other controls were mixed up.

First of all during the Gulf War ...

Down the tube

I see that an American colonel flying his F-15 along the Turkey/Iraq border had reason to use the small liquid-absorbing container with which his aeroplane was equipped. He undid a seat buckle or two and managed to get one of them stuck behind a side-mounted control lever. The aircraft hurtled earthwards in a high-speed tumble which proved irreversible and the colonel ejected just before impact, presumably having re-secured himself in the seat! He watched balefully as zillions of dollars'-worth of aeroplane exploded below him, thus establishing a world record for the cost of a spent penny!"

John Maynard's Crosswind column, Aeroplane Monthly, April 1994, p 63

Also Kai-Mikael recalls that the SAAB 35 Draken had controls moved around - to be precise the reconnaisance and fighter versions had switched levers for canopy release and drop-tank release. Normally this was not a problem, since a given pilot would only fly one of the versions, but there is one report (in Flygrevyn) of a fighter pilot who during an exercise had to fly the recce version. His belly drop tanks caught fire in a bad take-off and attempting to jettison them the pilot lost the canopy instead and then dropped the tanks in the wrong order causing instability in the plane, so he had to eject. Read Kai-Mikael's full story in /e3/online/draken-tanks

I also recall hearing about a pilot of a passenger aircraft, who on encoutering problems half way through take-off unaccoutably powered down all systems. During a subsequent invesigation it turned out that the pilot had been training extensively in a simulator as a slightly new version of the cockpit layout had been introduced and the simulator was being used precisely to avoid mistakes like thoise described above. Of course, in the simulator when things went wrong one simply rebooted and started again... Now is this another urban legend? Let us know if you have the real story!

Kai-Mikael remarked on the fact that fighter aircraft design during WW II has spurred much of the science of information ergonomics - in particular he points to the design of the German Fw 190, which had very carefully designed cockpits. This goes on today in aviation with extensive ergonomics and human factors staff at Boeing, British Aerospace and others.

Kai-Mikael also pointed out that the photo in the book is one of the very first production Spitfires - the flat canopy was very soon changed for the characteristic domed one, "to accomodate tall pilots", and that the pilot in the photo is Jeffrey Quill.