Ejection with sideslip

[F-16GUY]

https://www.youtube.com/watch?v=bz_Pc03Y5zI

After watching this video posted by SpazSinbad in another thread, I started to wonder if those highly tested ejection seats (90 tests for the MB US16E) are ever tested in a scenario where the aircraft (test setup) is subjected to a large amount of sideslip during the ejection process?

Reason behind my thought is that we lost a crew in a two-seater some 30 years ago during a failed ejection attempt. Their F-16 was involved in a mid-air collision and it was estimated that the aircraft was side-slipping with considerable speed when the ejection was initiated. The large and heavy canopy of the two-seater was affected by the airflow and came off sideways, hitting and damaging the top of the rear ejection seat and probably also the crewmember in that seat. The damage to the seat and the canopy-seat sequencing mechanism meant that the seats never got the "canopy out of the way" command, and therefore never fired.

I can think of many situations like mid-air’s, out of control and damage by enemy fire that would result in the aircraft not flying in a straight line during ejection, so I wonder if a possible sideslip is taken into account when escape systems are tested.

The above described accident by the way, resulted in the modification of the canopy-seat sequencing mechanism on all F-16's.

Some videos of possible sideslip during ejection scenarios:

https://www.youtube.com/watch?v=9QcrhF5ZlpQ
https://www.youtube.com/watch?v=xnWB-GeOwqc

[Just This Once...]

Yes, sideslip is considered and is one of the reasons the F-35 went for an explosively released transparency. The amount of sideslip capability required was an issue for the F-35 program as the USAF were (at least initially) content with more limited testing envelope than the B variant customers were looking for.

[F-16GUY]

JTO,

Do you by any chance have any references like pictures, videos or test reports? All the tests I have seen are either stationary or with the sled or test aircraft moving straight forward. Could be cool to see any pictures or slowmotion videos of an ejection during sideslip condition.

Another reason for not choosing the same type of canopy and canopy removal system for the F-35 as for the F-16 and F-22, is that it does not suit the maritime environment that the B and C model are intended to operate in. During an underwater ejection it would not be possible to remove a canopy like the massive F-16 type, and an ejection through it is not possible either.

[SpazSinbad]

Bang Seat Battle 16 Sep 2010 Bill Sweetman
“...The JSF ejection system design is challenging in several ways. The seat has to deliver high performance because a STOVL landing problem could mean ejecting at low altitude from a descending aircraft that is also yawed or pitched out of level flight....”
Ares (http://jouncier.rssing.com/chan-1702855/all_p6.html)
ORIGINAL: Ares | Aviation Week (http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%3a27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3a22e106eb-da6e-4f7f-9321-cb757d69823c&plckScript=blogScript&plckElementId=blogDest)
____________________________________

Martin-Baker: Saving Lives in the Family Way 15 Jun 2015
“...the US16E achieved a significant milestone, when it received the Release Authorization Notice (RAN) Level VI flight clearance from Lockheed Martin. Thus, the F-35 seat is now fully qualified for unrestricted flight operations....”
http://airsoc.com/articles/view/id/557fbcd5313944322c8b45c7/martin-baker-saving-lives-in-the-family-way

[Madbob]

This was an early Tornado loss where the pilot was killed and there was speculation that he may have been incapacitated by the canopy following the nav's ejection. I seem to recall that this happened at c. 15-20,000 feet as the aircraft was coasting-in crossing the north Norfolk coast returning at night to Honington. The aircraft had a total electrical failure and there ought to have been plenty of time for the pilot to follow the nav safely but this was I think before command ejection was introduced to the Tornado fleet.


MB




27th September 1983.RAF Tornado GR1ZA586/ A IX Sqn Night Flight. Crashed onto Wolfeston Marsh, six miles North of Kings LynnNavigator
Flt. Lt. N. Nickles ejected Martin-BakerSqn. Ldr. Michael Stephens, ordered the navigator to eject but failed to do so himself and was killed in the crash :(

[EAP86]

Madbob. I thought Tornado had command ejection from day one. If I remember that accident correctly (industry designation BT029?) its still on the books as cause unknown as they never managed to explain the 'total electrical failure' aspect.

From memory, the normal UK seat testing regime only looks at sideslip in front of Boscombe's blower tunnel to a maximum of 5 degress sideslip. The blower tunnel only looks at the ejection path clearance aspects up to 300kts (MDC or canopy jettison). The rest of the system testing only really looks at the 1g straight and level case. This isn't to say that all the combinations of climb/dive, speed, acceleration, roll and yaw, sinkrate and attitude aren't investigated, they are but its usually by calculation/simulation.

You can obtain a series of carpet plots for the performance of the ejection system wrt all these parameters from MBA but I suspect they're not widely published. They're impossible to memorise and not much use when it comes to the reality of an escape scenario.

I once asked a colleague (who knew about this stuff) why sideslip wasn't given more consideration. In answer I was told that in normal flight seats and canopies move predictably irrespective of sideslip. The exception of course is when the aircraft is stalled or spinning. In this case its almost impossible to investigate system performance in any meaningful way given the constantly varying external flow field in the wake of the aircraft.

EAP

[SpazSinbad]

The IDEAL side by side hand holding ejection mechanism. RAAF F-111C crew ejection OHAKEA, pilot went on to thrills landing an S-2E/G aboard HMAS Melbourne on exchange.

http://i98.photobucket.com/albums/l261/SpazSinbad/NewNewAllBum/F-111BescapeCapsule1forum.gif~original (http://s98.photobucket.com/user/SpazSinbad/media/NewNewAllBum/F-111BescapeCapsule1forum.gif.html)
http://i98.photobucket.com/albums/l261/SpazSinbad/NewNewAllBum/F-111BescapeCapsule2forum.gif~original (http://s98.photobucket.com/user/SpazSinbad/media/NewNewAllBum/F-111BescapeCapsule2forum.gif.html)
http://i98.photobucket.com/albums/l261/SpazSinbad/NewNewAllBum/F-111raafModuleOHAKEAforum.gif~original (http://s98.photobucket.com/user/SpazSinbad/media/NewNewAllBum/F-111raafModuleOHAKEAforum.gif.html)
http://i98.photobucket.com/albums/l261/SpazSinbad/NewNewAllBum/KellyRAAFejectF-111aboard1980S2forum.gif~original (http://s98.photobucket.com/user/SpazSinbad/media/NewNewAllBum/KellyRAAFejectF-111aboard1980S2forum.gif.html)

[tartare]

x2 .38s and 50 rounds.
Nice.