So I guess it's not only AMA fields that have the occasional safety lapse
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init4fun (11-07-2021)
11-07-2021, 03:09 AM
#3
I saw a few things going on that could account for the plane's failing to maintain flight:
- Speed called out the visible aileron being slightly down, that says the plane was out of balance due to the weight on the outside of the plane and on the left
- the flaps were fully extended, meaning the plane was flying slow and not making sufficient lift to maintain flight
- the plane was a twin turboprop with both props turning clockwise
11-07-2021, 04:26 AM
#4
My guess would have to be that the pilot was pushing full forward on the yoke to compensate for the rear weight since that would have been full down on the elevator. The reason I didn't mention it is I think the pilot would have reacted quick enough to bring the elevator back to center before the plane stalled. Unfortunately, what he should have done is leave the controls alone, allowing the plane to go into a dive and gave it a chance to build up some airspeed rather than fall off to the left and go into a tumble in the way it did
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init4fun (11-07-2021)
11-07-2021, 04:54 AM
#5
Seems to be a common issue with a King Air 90.
- Usually the guys flying jumpers are green time builder pilots.
-A twin doesn't have the same torque or P-Factor that a single engine.
-They try to get as high as they possibly can for the enjoyment of the jumpers. Thus at maximum altitude for weight to power to lift to drag.
- The roll to the left probably has more to do with the excessive drag, fast change in wt/bal., and an open door. And poor pilot skills allowing himself to get in this situation.
If you look on YouTube, this guy isn't this first to make this mistake. There are those who have, and those who will.
Here's another guy, could even be the same guy?
- Usually the guys flying jumpers are green time builder pilots.
-A twin doesn't have the same torque or P-Factor that a single engine.
-They try to get as high as they possibly can for the enjoyment of the jumpers. Thus at maximum altitude for weight to power to lift to drag.
- The roll to the left probably has more to do with the excessive drag, fast change in wt/bal., and an open door. And poor pilot skills allowing himself to get in this situation.
If you look on YouTube, this guy isn't this first to make this mistake. There are those who have, and those who will.
Here's another guy, could even be the same guy?
Last edited by RCFlyerDan; 11-07-2021 at 05:05 AM.
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init4fun (11-07-2021)
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init4fun (11-07-2021)
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init4fun (11-07-2021)
11-07-2021, 05:22 AM
#8
And I would agree with the torque and P-factor EXCEPT, when the the British requested to try the Lightning, they required the engines to use the same gear box on both sides and, due to US regulations, were not equipped with turbochargers. This was different than the USAAF planes that used two different gearboxes to counter rotate the props. While the USAAF planes were well mannered, the British versions were not. The RAF returned their planes to the US who quickly changed the gearbox and prop on one side and added the turbochargers, matching the the other planes used by the American pilots later, after the US joined the war effort
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init4fun (11-07-2021)
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init4fun (11-07-2021)
11-07-2021, 05:48 AM
#10
Watched this several times. Looks like:
A: the pilot slowed to Vmc or less, which would explain the roll to the left (left engine is critical on most conventional twin-engine aircraft)
B: the stall and Vmc induced roll occurred just before the exit
C: a Vmc induced roll does not require the critical engine to be failed. At 16,000', and at probably around 80kts, the thrust from the right side of the right propeller disc would be enough to cause this. And to a low-time pilotnit would be unexpected. Vmc demos are always done with the critical engine either shut down, feathered or set to zero thrust.
D: full flaps did not help the situation.
E: I'm not sure what 90 series King Air this is, but if it's an A or B model, they were woefully underpowered, which ironically would exacerbate this situation, especially at the altitude they were at
As Hydro said, if the pilot had simply lowered the nose, it would have dramatically helped.
R_Strowe
A: the pilot slowed to Vmc or less, which would explain the roll to the left (left engine is critical on most conventional twin-engine aircraft)
B: the stall and Vmc induced roll occurred just before the exit
C: a Vmc induced roll does not require the critical engine to be failed. At 16,000', and at probably around 80kts, the thrust from the right side of the right propeller disc would be enough to cause this. And to a low-time pilotnit would be unexpected. Vmc demos are always done with the critical engine either shut down, feathered or set to zero thrust.
D: full flaps did not help the situation.
E: I'm not sure what 90 series King Air this is, but if it's an A or B model, they were woefully underpowered, which ironically would exacerbate this situation, especially at the altitude they were at
As Hydro said, if the pilot had simply lowered the nose, it would have dramatically helped.
R_Strowe
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init4fun (11-07-2021)
12-29-2021, 01:04 PM
#11
Discussion about the Lightning and counter-rotating props caught my attention here - either I can be enlightened here or I've found something of genuine universal "head scratcher's" interest -
I used to think counter-rotating props on conventional twin-engine airplanes were used exclusively to avoid pilot overload in the event of an engine failure and the resultant asymmetric thrust situation but here's something to ponder...
Careful observation of the AAF Lockheed P-38 Lightning's prop directions show that they actually turn outward at the top of the prop arc; in other words, when sitting in the cockpit, the port engine propeller turns counter-clockwise while the starboard engine prop turns clockwise - since torque is opposite of propeller rotation - this would seem bass-ackwards and counter-intuitive with regard to torque or benefit away from the dead engine and actually roll the airplane toward the dead engine making both engines critical. Furthermore, spiraling slipstream would do the same here accentuating pilot workload. Therefore, it would lend extreme support to the ole sayin' that in a conventional twin with an engine out situation, the good engine simply takes you to the scene of the crash. I don't question the designers here and I'm sure there is sound reason for Lockheed doing this but I just don't know why it was done this way. Was either told or read somewhere it had to do with turning ability but can't see this being the case as balance of torque forces should work regardless of prop directions turning inboard or outboard with a counter-rotation setup.
With all that said, I could've sworn having seen an old training film in A&P school that featured an apparently talented, demo pilot (perhaps Tony LeVier in the style of Bob Hoover) maneuvering a cleaned-up, P-38 with one prop feathered at very low altitude and turning in both directions in tight turns and being fascinated by the whole deal but I can't find evidence now.
I used to think counter-rotating props on conventional twin-engine airplanes were used exclusively to avoid pilot overload in the event of an engine failure and the resultant asymmetric thrust situation but here's something to ponder...
Careful observation of the AAF Lockheed P-38 Lightning's prop directions show that they actually turn outward at the top of the prop arc; in other words, when sitting in the cockpit, the port engine propeller turns counter-clockwise while the starboard engine prop turns clockwise - since torque is opposite of propeller rotation - this would seem bass-ackwards and counter-intuitive with regard to torque or benefit away from the dead engine and actually roll the airplane toward the dead engine making both engines critical. Furthermore, spiraling slipstream would do the same here accentuating pilot workload. Therefore, it would lend extreme support to the ole sayin' that in a conventional twin with an engine out situation, the good engine simply takes you to the scene of the crash. I don't question the designers here and I'm sure there is sound reason for Lockheed doing this but I just don't know why it was done this way. Was either told or read somewhere it had to do with turning ability but can't see this being the case as balance of torque forces should work regardless of prop directions turning inboard or outboard with a counter-rotation setup.
With all that said, I could've sworn having seen an old training film in A&P school that featured an apparently talented, demo pilot (perhaps Tony LeVier in the style of Bob Hoover) maneuvering a cleaned-up, P-38 with one prop feathered at very low altitude and turning in both directions in tight turns and being fascinated by the whole deal but I can't find evidence now.
