Accelerated Slipstream
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Accelerated Slipstream
I would like to ask an aeronautical engineer a question. Are there any such fellows or ladies on here for me to ask? I don't know how to use this forum yet. To stupid.
I see that I have made it this far, so I'll ask my question. When taking off in an (twin propeller aircraft) such as the King Air b200 and just after rotation, the left engine quits. It is the critical engine, because both propellers rotate clockwise, viewing from the rear. According to eye witnesses the pilot kept the landing gear down and flaps extended. Reportedly it was estimated that he had attained an altitude of approximately 150 feet. It appears that he made a deliberate left turn to get over to the adjacent parallel runway. Eye witnesses said that when he made the turn, it appeared that everything was okay. He leveled out, but just after that his left wing dipped and he crashed into a flight training building. Witnesses stated that the landing gear remained down and flaps were still extended during the turn. Now I have read a great deal about the loss of the lift of the accelerated slipstream produced by the left propeller of the left engine when that engine fails. This loss of lift causes the left wing to drop and because of p-factor of the right propeller accelerated slipstream, this also causes a more dramatic roll to the left, especially at low speeds. Also the added drag of the left dead engine and wing causes a strong left yaw. It is therefor recommended to feather the dead engine asap, raise the gear when you are sure that you have Vmc and than retract the flaps and banking to the right about 5 degrees to correct yaw and roll. I have read that the loss of the propeller accelerated slipstream over the wings is greater and is lost during an engine failure at slow speed and high angle of attack in the take off configuration. However many pilots don't agree with the loss of the accelerated slipstream. My question is it a true factor that could prevent engine failure crashes if pilots were aware of it and know what to do? Or is it that, many people in aviation don't understand this? Do we need better training, not more but better? Three people in a flight training building died as well as the pilot in this accident. The plane had no additional load.
I see that I have made it this far, so I'll ask my question. When taking off in an (twin propeller aircraft) such as the King Air b200 and just after rotation, the left engine quits. It is the critical engine, because both propellers rotate clockwise, viewing from the rear. According to eye witnesses the pilot kept the landing gear down and flaps extended. Reportedly it was estimated that he had attained an altitude of approximately 150 feet. It appears that he made a deliberate left turn to get over to the adjacent parallel runway. Eye witnesses said that when he made the turn, it appeared that everything was okay. He leveled out, but just after that his left wing dipped and he crashed into a flight training building. Witnesses stated that the landing gear remained down and flaps were still extended during the turn. Now I have read a great deal about the loss of the lift of the accelerated slipstream produced by the left propeller of the left engine when that engine fails. This loss of lift causes the left wing to drop and because of p-factor of the right propeller accelerated slipstream, this also causes a more dramatic roll to the left, especially at low speeds. Also the added drag of the left dead engine and wing causes a strong left yaw. It is therefor recommended to feather the dead engine asap, raise the gear when you are sure that you have Vmc and than retract the flaps and banking to the right about 5 degrees to correct yaw and roll. I have read that the loss of the propeller accelerated slipstream over the wings is greater and is lost during an engine failure at slow speed and high angle of attack in the take off configuration. However many pilots don't agree with the loss of the accelerated slipstream. My question is it a true factor that could prevent engine failure crashes if pilots were aware of it and know what to do? Or is it that, many people in aviation don't understand this? Do we need better training, not more but better? Three people in a flight training building died as well as the pilot in this accident. The plane had no additional load.
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I have no knowledge of the specific mishap so my comments are generic only. Likewise I have not flown or been involved with KingAir 200s so allow for that as well.
Some observations ..
Are there any such fellows or ladies on here for me to ask?
Lots of such folk abound within PPRuNe so ask away ..
just after rotation, the left engine quits
An extremely critical situation. Adherence to the POH procedures, as a rule, will provide for the best chance of a successful outcome.
Immediate concerns are -
(a) DH
(b) OAT (for a turbine)
(c) GW (extremely critical to OEI climb capability)
(d) CG
(e) actual speed at the time of failure compared to target takeoff safety speed and Vmca
(f) Vmca may become quite vicious as the actual speed approaches the real Vmca for the conditions. Directional control difficulties increase very rapidly.
(g) presuming that your mishap aircraft is certificated to Part 23 (refer TCDS A24CE), while acknowledging that turboprops generally fare better than pistons, things will still be interesting, depending on the above conditions.
(h) if near Vmca, it is absolutely critical to adopt the POH technique .. unless the 5 degree bank requirement is specifically not required (and that would be most unusual) the bank is critical as the actual Vmca varies significantly (and rapidly) with bank variations .. bank into the operating engine (within reasonable limits) will improve the handling by reducing the actual Vmca. It does, on the other hand, not do all that much for climb gradient which, in general, is maximised at a bank angle around 2-3 degrees.
(i) if the POH configuration is not achieved, OEI climb gradient can be assumed to deteriorate severely ...
It is the critical engine, because both propellers rotate clockwise, viewing from the rear.
This is the general situation. At high angles of incidence, the net thrust vector will move outboard on the starboard propeller which increases directional control difficulties when contrasted to a starboard power loss. In the latter case, the port propeller thrust vector moves inboard.
the pilot kept the landing gear down and flaps extended
Possibly not a good idea unless the intention was an immediate landing. Given that you refer to a parallel runway, I presume that was the pilot's intent.
He leveled out, but just after that his left wing dipped and he crashed
Speculation only on my part - depending on speed control and manoeuvring loads, the aircraft may have fallen foul of a Vmca/stall situation with the port wing stall margin compromised further by the roll input to achieve the parallel runway heading.
loss of the lift of the accelerated slipstream
Clearly there will be a reduction in lift in the region normally swept by the slipstream. This is much more pronounced on larger four-engined turboprops such at the various Lockheed products. However, the POH procedures will have been developed with this effect being part of the flight test trials. Hence, providing that the handling techniques follow that recommended in the POH, the effect ought not to be overly critical in the scheme of things.
This loss of lift .. a more dramatic roll to the left, especially at low speeds.
Granted, but this will have been material in determining POH procedures.
added drag of the left dead engine and wing causes a strong left yaw.
Perhaps not so much a wing consideration but, certainly, on many turboprop installations if the propeller either is not feathered or NTS-ing .. the situation becomes very critical very quickly. See for instance the discussion on the Brasilia mishap at Darwin some years ago - (here).
Some observations ..
Are there any such fellows or ladies on here for me to ask?
Lots of such folk abound within PPRuNe so ask away ..
just after rotation, the left engine quits
An extremely critical situation. Adherence to the POH procedures, as a rule, will provide for the best chance of a successful outcome.
Immediate concerns are -
(a) DH
(b) OAT (for a turbine)
(c) GW (extremely critical to OEI climb capability)
(d) CG
(e) actual speed at the time of failure compared to target takeoff safety speed and Vmca
(f) Vmca may become quite vicious as the actual speed approaches the real Vmca for the conditions. Directional control difficulties increase very rapidly.
(g) presuming that your mishap aircraft is certificated to Part 23 (refer TCDS A24CE), while acknowledging that turboprops generally fare better than pistons, things will still be interesting, depending on the above conditions.
(h) if near Vmca, it is absolutely critical to adopt the POH technique .. unless the 5 degree bank requirement is specifically not required (and that would be most unusual) the bank is critical as the actual Vmca varies significantly (and rapidly) with bank variations .. bank into the operating engine (within reasonable limits) will improve the handling by reducing the actual Vmca. It does, on the other hand, not do all that much for climb gradient which, in general, is maximised at a bank angle around 2-3 degrees.
(i) if the POH configuration is not achieved, OEI climb gradient can be assumed to deteriorate severely ...
It is the critical engine, because both propellers rotate clockwise, viewing from the rear.
This is the general situation. At high angles of incidence, the net thrust vector will move outboard on the starboard propeller which increases directional control difficulties when contrasted to a starboard power loss. In the latter case, the port propeller thrust vector moves inboard.
the pilot kept the landing gear down and flaps extended
Possibly not a good idea unless the intention was an immediate landing. Given that you refer to a parallel runway, I presume that was the pilot's intent.
He leveled out, but just after that his left wing dipped and he crashed
Speculation only on my part - depending on speed control and manoeuvring loads, the aircraft may have fallen foul of a Vmca/stall situation with the port wing stall margin compromised further by the roll input to achieve the parallel runway heading.
loss of the lift of the accelerated slipstream
Clearly there will be a reduction in lift in the region normally swept by the slipstream. This is much more pronounced on larger four-engined turboprops such at the various Lockheed products. However, the POH procedures will have been developed with this effect being part of the flight test trials. Hence, providing that the handling techniques follow that recommended in the POH, the effect ought not to be overly critical in the scheme of things.
This loss of lift .. a more dramatic roll to the left, especially at low speeds.
Granted, but this will have been material in determining POH procedures.
added drag of the left dead engine and wing causes a strong left yaw.
Perhaps not so much a wing consideration but, certainly, on many turboprop installations if the propeller either is not feathered or NTS-ing .. the situation becomes very critical very quickly. See for instance the discussion on the Brasilia mishap at Darwin some years ago - (here).
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Thank you so much for your incite. I know that most people don't approve of anyone attempting to understand these things. It is so tragic and I do need to be respectful for the mistakes of others. I was just looking for a prevention, if it is better training or reminding each other from time to time. I've only flown a single. Back in the 1950's my uncle taught me in his piper J-3 Cub. He made a fatal mistake one day. I've never had the money to get my training. The only thing that I fly today is a game sim. I now do critical engine failure just after rotation in an Air King 350. Even in the MSF simulator I have to act quickly, because of the roll and yaw. Got to get the gear up quick or it drops below Vmc. Best regards, friend.
PS.
I had typed up more info on the accident, but thought that I would offend someone if I posted it. But if you would like to know more I will be glad to give you the info.
Just in case you want to know more. The simulation video is not entirely correct. It was done before all the eye witness had made their statement. I hope that I'm not violating any of the guidelines of this web site. If I am, I am sorry for my ignorance.
http://abcnews.go.com/GMA/video/smal...chita-26597222
http://aviation-safety.net/database/...?id=20141030-0
http://www.bizjournals.com/wichita/b....html?page=all
PS.
I had typed up more info on the accident, but thought that I would offend someone if I posted it. But if you would like to know more I will be glad to give you the info.
Just in case you want to know more. The simulation video is not entirely correct. It was done before all the eye witness had made their statement. I hope that I'm not violating any of the guidelines of this web site. If I am, I am sorry for my ignorance.
http://abcnews.go.com/GMA/video/smal...chita-26597222
http://aviation-safety.net/database/...?id=20141030-0
http://www.bizjournals.com/wichita/b....html?page=all
Last edited by oldman04271940; 16th Dec 2014 at 22:50.
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Even in the MSF simulator I have to act quickly, because of the roll and yaw. Got to get the gear up quick or it drops below Vmc.
I only have a few hours flying the King Air B200, but nearly all of it was doing simulated loss of thrust, and Vmca testing. The B200 is an excellently capable aircraft in this respect. It has a little known special condition for its certification, recorded in an FAA letter written to Beechcraft on October 15, 1973, which in part acknowledges that the B200 can achieve skid angles as much as 35-40 degrees while flying on one engine. The letter goes on to state that the aircraft is easily recoverable in this condition. I have done this testing, and can confirm that it is very able to be safely flown in these extreme conditions. I opine that this cannot be simulated.
I have no knowledge of the circumstances of the sad accident to which you refer, but I can state with total confidence that there are no "hidden corners" in the handling of the King Airs, or any other FAA certified type, which are not accounted for in the Flight Manual information. Just sometimes bad stuff happens.....
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Thanks for your response.
Yes sometime we (People) do things, that later we ask ourselves, why did I do that. Sometimes my mind scrambles and scatters during a stressful moment. I have found myself many times in my life at a loss of what to do next. Sometimes it takes a few moments to get ahold of the situation. Yes, you are very correct about sims. I remember the feelings that I had when my uncle was teaching me aerobatics in his little cub, back in the 50's. At least those that it could handle without ripping the fabric off the wings. There is also no comparison of the behavior of the aircraft. Not realistic at all. These game sims are much more difficult, especially on approach and landings. You swing around like a monkey on a long swing, continuously over swinging. They are actually no fun at all. They are for kids of course. I seldom play it, except to chase a UFO down. I'm so bored with life, that I play on occasion. It appears that the King Air is a very strong and safe aircraft then? That much of a skid it would seem to me, from what I have read about other aircraft is amazing. Perhaps overconfidence of the air craft to do a sharp turn into a dead engine before reaching a safe speed, was one factor. We will just have to see what the NTSB findings are. So sad to loose an aviator as well as others. My uncle was an old Army Air Corps fighter pilot and his crash was caused by him being over confident I suppose. He and mom's brother would take their shotguns with them and would fly low and slow and shoot at coyotes. I still remember seeing the skeleton of the tubing framework sticking tail up at about 45 degrees. A very sad day. Lost 2 uncles.
Yes sometime we (People) do things, that later we ask ourselves, why did I do that. Sometimes my mind scrambles and scatters during a stressful moment. I have found myself many times in my life at a loss of what to do next. Sometimes it takes a few moments to get ahold of the situation. Yes, you are very correct about sims. I remember the feelings that I had when my uncle was teaching me aerobatics in his little cub, back in the 50's. At least those that it could handle without ripping the fabric off the wings. There is also no comparison of the behavior of the aircraft. Not realistic at all. These game sims are much more difficult, especially on approach and landings. You swing around like a monkey on a long swing, continuously over swinging. They are actually no fun at all. They are for kids of course. I seldom play it, except to chase a UFO down. I'm so bored with life, that I play on occasion. It appears that the King Air is a very strong and safe aircraft then? That much of a skid it would seem to me, from what I have read about other aircraft is amazing. Perhaps overconfidence of the air craft to do a sharp turn into a dead engine before reaching a safe speed, was one factor. We will just have to see what the NTSB findings are. So sad to loose an aviator as well as others. My uncle was an old Army Air Corps fighter pilot and his crash was caused by him being over confident I suppose. He and mom's brother would take their shotguns with them and would fly low and slow and shoot at coyotes. I still remember seeing the skeleton of the tubing framework sticking tail up at about 45 degrees. A very sad day. Lost 2 uncles.
Last edited by oldman04271940; 17th Dec 2014 at 03:06.
