Westwind crash in Oklahoma City

Inverted

#inspirationing
I don’t see the problem with speculating as long as we aren’t trying to blame the pilots before a report is known.

There’s no way there was a gust of wind strong enough that day to cause this like the witness said.
I believe over 90% of all aviation accidents involve pilot error.
 

NovemberEcho

Dergs favorite member
Heres another Westwind that went off the runway due to a inadvertent single thrust reverser deployment. Per reddit, some are saying it bounced on landing (which goes with the previous post saying “a gust of wind lifted the nose”). Hard landing causing a bounce and TR deployed, just airborne enough to start a roll?

 

Crop Duster

E pluribus unum
Heres another Westwind that went off the runway due to a inadvertent single thrust reverser deployment. Per reddit, some are saying it bounced on landing (which goes with the previous post saying “a gust of wind lifted the nose”). Hard landing causing a bounce and TR deployed, just airborne enough to start a roll?

Without running numbers... simply by principles... this makes complete aerodynamic sense. The LEFT TR deploys as the aircraft is settling with residual speed - high enough speed to create significant aerodynamic effects. The left TR causes an asymmetrical drag moment along with a left-pulling asymmetrical yaw moment. The nose lifts slightly due to the downward (behind the fulcrum) drag moment induced by the TR at the tail. The right wing AOA increases as the tail drops and the nose is pulled to the left. The right wing's increasing AOA causes a lift moment on the right side. The lift on the right increases the AOA on the left. The whole aircraft starts to pitch up. The nose lifts. The nose loses it's friction-induced impediment to lateral motion. The left yawing moment causes the nose to veer left as it lifts... which increase left wing AOA, and lift, and left-banking tendency. The combined forces cause the aircraft to ground roll (not the taildragger type, but an actual roll) to the left. The aircraft ends inverted.
 
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Inverted

#inspirationing
Without running numbers... simply by principles... this makes complete aerodynamic sense. The LEFT TR deploys as the aircraft is settling with residual speed - high enough speed to create significant aerodynamic effects. The left TR causes an asymmetrical drag moment along with a left-pulling asymmetrical yaw moment. The nose lifts slightly due to the downward (behind the fulcrum) drag moment induced by the TR at the tail. The right wing AOA increases as the tail drops and the nose is pulled to the left. The right wing's increasing AOA causes a lift moment on the right side. The left yawing moment causes the nose to veer left. The airplane ground rolls (not the taildragger type, but an actual roll) to the left. The aircraft ends inverted.
The thrust is fairly close to centerline, not sure the TR deployment would cause a roll like that but if they got slow and had a high angle of attack, the airplane could have been close to stall and the TR dragged the nose over with yaw.
 

Crop Duster

E pluribus unum
The thrust is fairly close to centerline, not sure the TR deployment would cause a roll like that but if they got slow and had a high angle of attack, the airplane could have been close to stall and the TR dragged the nose over with yaw.
Yeah. That could happen too. My overarching point is there are ways this accident could be explained outside the realm of botched landing or gross pilot incompetence.

Whatever the cause, RIP to the crew. Lets all be careful out there and stay at least 5 minutes ahead of our aircraft. It seems things are getting frisky lately.
 

Pilot Fighter

Well-Known Member
Premature + asymmetric TR deployment could be messy.

This one stings a bit because I always dreamed of owning and flying some flavor of this aircraft. Did a bunch of back-of-the-napkin business plans. Something about that big straight wing spoke to me.

Sorry to hear the crew had JC connections.
 

tomokc

Well-Known Member
I’m a recip guy and don’t understand why TRs can be deployed independently. The accident involving N793BG presents an argument why they shouldn’t. What is the benefit of this independent control?
 

Skåning

Well-Known Member
I’m a recip guy and don’t understand why TRs can be deployed independently. The accident involving N793BG presents an argument why they shouldn’t. What is the benefit of this independent control?
Normally asymmetric deployment is not a big deal. Unless you’re still in the air. I’ve had the A320 with a t/r MEL’d, with the nose on the ground it’s surprisingly little yawing moment with full reverse on the good engine.
 

somewhereupthere

Well-Known Member
Word on street is the captain smacked one in somewhere once before due to landing technique. Merged a tip-tank with runway surface, wrinkled wing and airframe and it became a totaled aircraft. Everything was all hush hush.

Witness to this crash (a long in the tooth high time WW driver) says power was applied as if going around, it wobbled, rolled inverted and pancaked.

Armchair investigator theories are TR piggyback popped up inadvertently when throttles slammed to forward stops causing a TR deployment with slow speed (basically same thing that happened in the synfuels crash), with high alpha and basically asymmetrical full thrust.

I don’t mean to disparage the deceased but the prior incident is concerning.

As an 1124 guy myself I’m eager to find out if it’s time FAA issues AD for WoW sensing to be implemented into the TR circuitry logic. I can’t remember so correct me if I’m wrong, but the 1125 has WoW built into circuitry yeah? Or am I thinking 1126?
 
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Autothrust Blue

"I'll take your case."
I’m a recip guy and don’t understand why TRs can be deployed independently. The accident involving N793BG presents an argument why they shouldn’t. What is the benefit of this independent control?
In short, one is generally better than none, and it's also handy to be able to control them individually.
 

Autothrust Blue

"I'll take your case."
As an 1124 guy myself I’m eager to find out if it’s time FAA issues AD for WoW sensing to be implemented into the TR circuitry logic. I can’t remember so correct me if I’m wrong, but the 1125 has WoW built into circuitry yeah? Or am I thinking 1126?
Being unfamiliar with the conditions under which that airplane is certificated...er...you mean you can select reverse WoffW *and* get deployment?
 

tomokc

Well-Known Member
I don’t mean to disparage the deceased but the prior incident is concerning.
But you DID disparage Doug in your post. I've also heard speculation about Britton's actions that may have resulted in this accident. No one knows or will likely ever know: No FDR was installed, and the CVR was inop. The witness statements are inconsistent and the surveillance video footage is of an inadequate quality to determine.

The single TR deployment isn't "armchair investigator theories" - it's in the NTSB prelim: "The left thrust reverser was unlatched and open and the right thrust reverser was closed and latched."

If you have any specific and relevant information regarding a Westwind accident involving Doug Durning, you're welcome to post. Otherwise you're using that as fodder to blame him for this accident.
 

FlySooner9

Well-Known Member
I’m not buying that a TR deployment alone caused that crash. At the point it deployed they would be at a low power setting. Just don’t see it causing that much of a roll to invert the thing.
 

tlove482

Well-Known Member
I’m not buying that a TR deployment alone caused that crash. At the point it deployed they would be at a low power setting. Just don’t see it causing that much of a roll to invert the thing.
Checking the TRs with idle power on taxi takes you off center line. I'm pretty sure all that drag in the air at +100 knots would roll you
 

Crop Duster

E pluribus unum
Checking the TRs with idle power on taxi takes you off center line. I'm pretty sure all that drag in the air at +100 knots would roll you
Lol. Taildragger pilot says, "not if you use appropriate rudder during your check." The alternative secret is to check 'em during your hard taxiway turns in opposition to the desired direction of turn. That way, nobody even notices. :)
 

FlySooner9

Well-Known Member
Checking the TRs with idle power on taxi takes you off center line. I'm pretty sure all that drag in the air at +100 knots would roll you
Guess they have way more drag then on a CE-680

Still surprised it would cause a snap roll like that. Figure it’d be more yaw then a roll.
 

Pilot Fighter

Well-Known Member
As an 1124 guy myself I’m eager to find out if it’s time FAA issues AD for WoW sensing to be implemented into the TR circuitry logic. I can’t remember so correct me if I’m wrong, but the 1125 has WoW built into circuitry yeah? Or am I thinking 1126?
Do any of the WW's have WoW linked to TR? I thought WoW was only linked to lift dump.
 
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