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F-15 Elmendorf Crash Report

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F-15 Elmendorf Crash Report

Old 25th Apr 2019, 06:20
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Ecce Homo! Loquitur...
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F-15 Elmendorf Crash Report

My first thought was what was the base height for DACT? Fighting down at 5-6K and departing into an inverted flat spin makes me think the pilot was incredibly lucky to survive.

https://www.military.com/daily-news/...ve-g-spin.html

“....The pilot in the mishap aircraft was maneuvering defensively in relation to the F-22 at an altitude of about 5,400 feet, and traveling at about 180 knots, or 207 miles per hour, according to the report. Then the pilot initiated a vertical climb, bringing the F-15 to a nose height of 65 degrees, "20 degrees of right bank, 39 degrees Angle-of-Attack," flying at 1.2 Gs. The plane reached an apex of 6,300 feet, traveling 105 knots or 120 mph, the report stated.......

But the pilot did not feel the plane was flying as desired, and attempted to break the AOA -- or the angle between the reference line of a wing or the airplane itself to the relative oncoming wind -- and get the nose tracking faster during the perceived right turn, the report states. The pilot forced the plane's forward stick with full right rudder in an attempt to propel the jet in the chosen direction. Instead, the nose "pitched down and to the right to 65 degrees nose low, 110 degrees of right bank, -26 degrees AOA and G-forces decreasing from 1.2 to -0.3 Gs," according to the report.

By entering negative G-forces, or a downward acceleration faster than the rate of natural freefall, the aircraft "experienced a negative G departure from controlled flight with a snap roll entry to the left that transitioned to an inverted, negative G spin," investigators said........


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Old 25th Apr 2019, 06:34
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I know the F-15 is good, but honking it around at 105 kts seems a recipe for 'something going wrong'.
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Old 25th Apr 2019, 07:31
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Originally Posted by ORAC View Post
My first thought was what was the base height for DACT? Fighting down at 5-6K and departing into an inverted flat spin makes me think the pilot was incredibly lucky to survive


It’s not unusual to use a 5k Base Height for ACT. But you do have to be ‘decisive’ if you depart controlled flight at that height. I agree that the pilot was fortunate to get out!
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Old 25th Apr 2019, 09:40
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Well, at least there wouldn’t have been any argument about whether it was a hard floor kill......

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Old 25th Apr 2019, 12:41
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Yes, hard manoeuvring at base height should be approached with caution! Lamp-swinging warning!


One balmy afternoon, when the earth was cooling, I was indulging in 1 v 1 ACM in a Grey Jumping Bean over the Med. Misshandled low-speed scissors at base height resulted in a full power, braking-stop nozzle down departure at 5,000'. Rate of descent over 10,000 fpm, yaw rate approaching 360 degrees per sec, perfectly wings level with IAS pegged below 30kts.

HMMM!

Said Jumping Bean required c 5,000' to recover from the vertical and I was already way below recommended bang-out height in a spin (10,000'). I slammed the nozzles aft, which resulted in a 90 degree pitch down and I can well remember seeing the nadir star superimposed on the aircraft symbol with a height of 3,000' in the HUD.

Luckily I had been the Jumping Bean display pilot and followed my mentor's advice on recovery from a LL c*ck-up: - full power, trip the limiters and pull to 8 units ADD.

Bloody marvelous! Levelled off at 1500' and called "knock it off!"

i gave my #2 that one - and a beer!

Mog
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Old 25th Apr 2019, 13:52
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So, as the report says

nose height of 65 degrees, "20 degrees of right bank, 39 degrees Angle-of-Attack," flying at 1.2 Gs. The plane reached an apex of 6,300 feet, traveling 105 knots or 120 mph, the report stated.......
the pilot thought it sensible to shove the stick forward (probably not a bad plan) but put in full right rudder?!!

Now, the Harrier loved the whole slow speed thing and as Mogwi says you spent a lot of time at base height at low energy managing the fight. Are we really getting to a state now where pilots think the can whang the stick about, no matter what height or energy level you are at and the jet will sort it out? Unbelievable
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Old 25th Apr 2019, 15:51
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Anyone knows where I can find the report?
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Old 25th Apr 2019, 16:31
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Originally Posted by Flap62 View Post
Are we really getting to a state now where pilots think the can whang the stick about, no matter what height or energy level you are at and the jet will sort it out? Unbelievable


The report talks about the visual illusions with the false horizon and the guy didn't know he was climbing and thought he was pulling roughly level with more speed in hand. The flight control system at high AoA is not that helpful with its desire for 1G even when in a spin, compounded by the aft CofG and whatever radome induced issues carried on the jet. Use of rudder at high AoA is an F-15 thing due to the reduced roll authority, as is the use of asymmetric thrust.

With the departure warning tones and the nose wandering the forward stick unload probably felt like the right call and is the one called for in the cards, but the aircraft had departed with negative G and with abundance of hindsight an aft stick input was needed. This type of departure was not reflected in the drills nor was it practised in sim.

The guy whacked into the sea without a fully-developed canopy after the ejection seat modes also worked against him. It must have hurt like hell and he did well to survive and see his young family again.
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Old 25th Apr 2019, 19:31
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"Because of the forces pinning the pilot to right side of the aircraft, a first ejection attempt was unsuccessful, officials said. A second attempt was successful, but the plane had lost altitude, forcing the pilot to eject at 1,100 feet."
feet.

Previous F15D accident in UK had reference to radome influences in similar circumstances..
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Old 26th Apr 2019, 01:32
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Salute!

Thanks Just and Mog, good stuff

And @ Flap..... The new planes are almost what you describe. Move stick (and maybe a bit of rudder) to where you want to go and the thing will do whatever it takes to get you there. Clever pilots can still get to corners of the envelope where the best efforts of the control surfaces and Hal's commands to them are not enough. But usually you do not wind up in a spin or deep stall. Nose falls thru, speed increases, controls work again and fight's on. Did my tail slide in a Viper hundred years ago, and the gal got good air over the control surfaces once nose fell thru and I was flying again. I did it by zooming almost 90 degrees and got too slow before pulling back into the bandit.

The rule of thumb in the Viper those early days was if the nose was still responding, then don't let off the back stick. The early deep stall guys got there by zooming and unloading too long. Speed got too slow for the elevator to get the nose down and some of the time you would get into the classic deep stall.

The first Eagle encounters we had clearly showed that plane's great nose authority when slow and we had to adapt our tactics. We could go up with them to their surprise, but we had problems at the top due to our AoA limiter. Remember that only 10 years after VietNam we were getting down to WW2 speeds. In the late 60's and early 70's nobody wanted to get slow in the F-4 or F-8.

Sad to see loss of the jet, and also glad the dude got out.

Gums sends...
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Old 26th Apr 2019, 14:38
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https://media.defense.gov/2019/Apr/2...E%20REPORT.PDF

Full report if anyone wants to read it...
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