Jim C.

i personally, was talking about U.S aircraft.. sorry if it came across diffrently. forgot to add the harrier also!

Chevelle

My Feedback: (2)

The three thrust-vectoring aircraft at Edwards, California, each capable of flying at extreme angles of attack, cruise over the California desert in formation during flight in March 1994. They are, from left, NASA's F-18 High Alpha Research Vehicle (HARV), flown by the NASA Dryden Flight Research Center; the X-31, flown by the X-31 International Test Organization (ITO) at Dryden; and the Air Force F-16 Multi-Axis Thrust Vectoring (MATV) aircraft.

FHHuber

its simple... he had an extreme case of high speed stall. The wing was just acting as an airbrake instead of producing useful lift.

The pilot on realizing that he had to pull harder to not hit the ground found that pulling harder did no good. Sure the plane pointed different... and maybe the descent even slowed some (very high G load would be involved here..) But any plane can only pull so many G's at a given speed before the wing stalls.

He probably punched out just as the thing's stall buzzer tripped. (Hmm going down fast... wing stalled... no room... I'm outa here... POOF!)

LarryLudwig

The reason that the F-16 impacted the runway is because he simply exceeded his Alpha. (AOA) The F-16 has the ability (as do most fighters) to create enough deflection in the tail surface to rotate the a/c about the horizontal axis more rapidly than the machine can "fly itself" out. You have heard all the "Hotshots" quick to point out that they "push the envelope" well... this pilot simply exceeded the envelope. (It is easy to push it... getting it BACK is the trick)

The altitude error is because of the confusion between MSL and AGL altitudes.
If the field elevation was 1500' then the altimeter would read 1500' when you powered up your cockpit. However your RADAR alitimeter would read ZERO.

The pilot made the mistake of using an incorrect field elevation. The comment that you are supposed to check the altimeter at the top of the maneuver before commencing is actually a cross check that you are entering your maneuver at the correct altitude. You are supposed to be within 50' of your entry window.

If however you start with the wrong value (i.e. 1000 too low) you are going to endup that much wrong at the other end.

As far as the impact being nose up... if he had a little more altitude the nose would have been even higher, and he still would have impacted. Inirtia exceeded lift. He exited the flight regime envelope with the excessive pitch attempt... and at that point he became a passenger as he was no longer controlling the a/c. Had he enough room to recover, the spectators would have been treated to something even more spectacular than a crash, but a Viper powering out of the situation. With 48,000 lbs thrust on a 35,400 lb a/c he could have pulled it into what was known in the 60's as a "Saber Dance" due to the F-100 SuperSaber that exceeded his Alpha and had the plane hovering off the runway on thrust alone. He snaked it down the runway until finally losing control and crashing. The Viper's thrust to weight ratio is greater and would allow you to power out from that particular position.

Unfortunately, he didn't have the room and was damn lucky to get out.

As to the Airshow continuing. I am sad to say that I have participated in Airshows both in USA as well as England and France. I have seen crashes occur all over. Sometimes the show goes on, sometimes it stops. If it is a major show... you can bet that it will continue. I was flying in the CAF AIRSHO 81 when the Seafury went in, and they resumed that show within 10 minutes.

Having seen so many spectacular "fake" photos recently with the technology available... I thought certainly that the picture was indeed a fake, but upon remembering the crash, I thought that it might well be real. I already had some trouble in that regard, since the airline I was flying for was getting new B-757's... I had an aviation buff "paint" one in our livery... digitally... then I got the funny idea to have him paint a B-757 ER instead. Since we had no pilot contract for this plane, when I posted the picture on the union website... all hell broke loose because everyone started screaming about payscales, and who was going to get to fly it... etc. When the word got out that it was a fake, there were PLENTY of p.o. 'ed people..... and well.. you know what they can do to themselves if they can't take a joke.

Captain Larry Ludwig USAF ret.

juvatwad

My Feedback: (8)

Yeah, I don't understand why this is so confusing to some. He entered the maneuver too low; regardless of the attitude of the nose of the jet, his lift vector was still descending, which isn't related to the AOA necessarily. I doubt the jet was stalled, although we can't know for certain, but ANY airplane with a descending lift vector will hit the ground eventually.

skythumbs

Another site showing all the videos and pictures.

http://www.avweb.com/newswire/10_06a.../186633-1.html

skythumbs

The offical report is as follows

Pilot error caused a U.S. Air Force Thunderbirds F-16 to crash at an air show on Sept. 14 at Mountain Home Air Force Base, Idaho, the Air Force said on Wednesday. (See below for in-cockpit video of the crash.) The pilot incorrectly climbed to 1,670 feet AGL instead of 2,500 feet before initiating the pull-down to the Split-S maneuver, according to the Air Force news release. The pilot, Chris Stricklin, 31, apparently flew by mistake to the MSL altitude used when practicing the maneuver at his home base, Nellis AFB in Nevada, which is 1,000 feet lower than the Idaho field elevation. The pilot ejected just eight-tenths of a second before impact, after reportedly making an effort to steer the aircraft away from the crowd of about 85,000 ... and now works at the Pentagon, in Washington, D.C. Stricklin suffered minor injuries. The F-16, valued at $20.4 million, was destroyed.

When Stricklin realized something was wrong, he exerted maximum back stick pressure and rolled slightly left to ensure the aircraft would impact away from the crowd should he have to eject, the Air Force said. He ejected when the aircraft was 140 feet above the ground. There was no other damage to military or civilian property. Also, the board determined other factors substantially contributed to creating the opportunity for the error to occur, including the requirement for demonstration pilots to convert AGL elevations to MSL altitudes, and performing a maneuver with a limited margin of error. Instead of just zeroing the altimeter to deck level as a result of the crash, procedures have been changed to require that Thunderbird pilots climb an extra 1,000 feet before starting the Split-S maneuver. Pilots must also call out their altitude to the ground safety operator in MSL rather than AGL numbers.

bruzer

juvatwad.....The lift vector on a wing is always pointed perpindicular to the wing and up from the surface of the wing. I think you meant to say that, for lack of a better term, the inertial vector was pointed down. I do not mean to put anyone off but being an aerospace engineer I just can't let the incorrect assumptions in this forum go on anylonger. I apologize but I just can't stay away anymore.

If this offends anyone well.... sorry

juvatwad

My Feedback: (8)

Bruzer, you're right. I was just trying to put it in overly simple terms and eliminate considerations of stall, excessive AOA, etc.

Jim C.

yeah .. i tried to explain it to them too but we have a bunch of keyboard know it alls around. and that photo is from 94 this is 2004 and the vectored thrust was explained too.. some people need to get with the times..

tagman

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juvatwad

My Feedback: (8)

Roger that, GraupnerFan.

Jim C.

lol great addon tagman! its funny, i always see someone with ones i have. i make sure no one else has them but sure enough, somone else gets it too. theres no copyright on it.. so technically its not yours if its on the web... sorry

FHHuber

Atually... its technically yours and has a copyright by default if you publish it. Just n one everpays attention to that. If you can prove (yeah... right) you were the originator, you can attempt to enforce the copyright. (but it costs more than its worth for some crummy bitmap...)

Jim C.

oh crap... your right.. i forgot about that.... well allow me to retort.

tagman

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Jim C.

tagman

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tagman

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Jim C.

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NickC5FE

My Feedback: (31)

its funny reading the "facts" of this case on these forums. Ludwig and skythumbs got it right way back when when they talked about the field elevation being incorrect. However, the F-16 does not have the authority to outmanouver itself to more AOA than is feasibly possibly by the wing at any given aoa, airspeed and altitude. The digital flight control computer (DFLCC) WILL NOT LET THE PILOT PUT THE AIRCRAFT INTO AN UNSAFE CONDITION. The only way to over exagerate the stabs on an F-16 is to hit the "Manual Pitch Override) switch, and this is used in extreme flat stalls only. I have spoken with some of our Instructor Pilots here at Luke, and on a few occasions they get into such deep stalls that they use this button to "rock" the aircraft for and aft to get a nose down attitude to exit the stall. Another thing is that the F-16 has used thrust vectoring in the past. The "MATV, Multi Axis Thrust Vectoring) F-16 Flew first i believe in 1994 and flew successfully. Well i just thought i would chime in. Oh and for sh$ts and grins, does anybody know what the maximum AOA is for the F-16???? 25 DEGREES!!!!WOW

Jim C.

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juvatwad

My Feedback: (8)

Actually, the viper can fly into an "unsafe condition" as pantherflyr puts it, and vipers can go out of control. Again, the computer can handle one assaulted limiter (eg extreme pitch), but assaulting two limiters (eg pitch and roll or pitch and yaw) can (and has) accounted for F-16's going out of control. The inablility to put a viper out of control is a myth.

NickC5FE

My Feedback: (31)

juvatwad, you are right and that was what i was trying to say about going into an out of control condition.. The Jet will do everything to maintain stability, but in the rare instances that they do go out, the pilot can select manual pitch override to get out of the situation more often than not. I dont even remember why i posted a reply on here, i think it was because it sounded like a bunch of Lockheed engineers talking about a debrief of a crash, before it was ever really determined what happened??? However the case, I guess all you can say is, the pilot screwed up, YES HE SCREWED UP, and the f-16 is like a contradiction to aerodynamic theory, super controllable but yet just as stable (due to a bad ass DFLCC). nICK

multicasting

Does anyone recall what the malfunction was that occured to the lead of the Tbird team in 1982 that caused the entire flight of T-38s to fly into the ground in line abreast formation?