Jazz Hard Landing Report
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Re: Jazz Hard Landing Report
Edited
Last edited by jjj on Wed Dec 09, 2009 11:28 pm, edited 1 time in total.
Re: Jazz Hard Landing Report
Who cares about the camera, what's up with the autopilot on until 40'?
Re: Jazz Hard Landing Report
Although this is my own personal opinion and not based on any fact;
I wouldn't be suprised if the f/o's experience on turboprops and limited jet time was a contributing factor in not reducing the power to idle at the required altitude. The mild distraction of the crosswind could have allowed his actions to go to the routine he had been used to with the previous aircraft he had flown.
Most people who fly them know that if you reduce power to idle at 30-50 ft in a turboprop, in a short time you will be having a bad day.
BTD
I wouldn't be suprised if the f/o's experience on turboprops and limited jet time was a contributing factor in not reducing the power to idle at the required altitude. The mild distraction of the crosswind could have allowed his actions to go to the routine he had been used to with the previous aircraft he had flown.
Most people who fly them know that if you reduce power to idle at 30-50 ft in a turboprop, in a short time you will be having a bad day.
BTD
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Re: Jazz Hard Landing Report
BTD you probably nailed it. It's a tough habit to break when you get on the jets.
Re: Jazz Hard Landing Report
BTD, for the rest of us that don't fly turboprops or bigger eqp, please expand on the behaviour of the turboprop at 30-50 ft. Just curious...BTD wrote: Most people who fly them know that if you reduce power to idle at 30-50 ft in a turboprop, in a short time you will be having a bad day.
BTD
Thanks.
joco
Re: Jazz Hard Landing Report
Big props producing less power and turn into pretty much barn doors. If I'm not mistaken the props turn more into a disking position thus giving a greater surface area into the wind.
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Re: Jazz Hard Landing Report
if you pull the power on a prop-job, you stop flying almost now. We always have a little power on right til the flare, and even then you ease off slowly to let the plane settle in. Props make great brakes, if you get caught high and fast
On a Jet, especially a heavy one, when you go from approach thrust to idle, the only thing that happens quickly is the nose drops(on planes with engines under the wings). The plane takes forever(it seems) to slow down, and if you're approach is too fast, and you try to flare, you'll only float. This is why it's so important to fly the correct bug speed on a jet... energy management. Typically I don't go to idle thrust until I am fully committed to the landing, since to get the power back after idle will cause you to age a couple years.
On a Jet, especially a heavy one, when you go from approach thrust to idle, the only thing that happens quickly is the nose drops(on planes with engines under the wings). The plane takes forever(it seems) to slow down, and if you're approach is too fast, and you try to flare, you'll only float. This is why it's so important to fly the correct bug speed on a jet... energy management. Typically I don't go to idle thrust until I am fully committed to the landing, since to get the power back after idle will cause you to age a couple years.
Re: Jazz Hard Landing Report
Joco, just to expand on what has been said already;
When you are flying a turbo prop on approach, you will more than likely have your prop control/speed levers in a full forward position commanding maximum RPM. With torque being applied to the props there is no problem, the blades will adjust their blade angle to maintain the desired RPM (whatever the max is). When power is reduced to idle, the props are still trying to maintain the commanded RPM. With no additional torque, the only way for them to be able to do this is to position towards full fine. You effectively now have a windmilling propeller with the blade flat facing the direction of flight. As was said above it becomes like a giant plank of plywood outside, and your airspeed will rapidly decay. For this reason, most turboprop drivers carry power right until the aircraft is on the ground. Once on the ground the power can come back to flight idle, and into beta/reverse.
In the above report it discusses the logic for the spoiler/GLD devices. One of the conditions being position of the thrust levers. It could have been a contributing factor. The F/O had plenty of time 4000 hrs or so, but only 100 hrs jet. Old habits die hard, and in a moment of inattention your natural reflex takes over.
This is purely my opinion, and nothing more.
BTD
When you are flying a turbo prop on approach, you will more than likely have your prop control/speed levers in a full forward position commanding maximum RPM. With torque being applied to the props there is no problem, the blades will adjust their blade angle to maintain the desired RPM (whatever the max is). When power is reduced to idle, the props are still trying to maintain the commanded RPM. With no additional torque, the only way for them to be able to do this is to position towards full fine. You effectively now have a windmilling propeller with the blade flat facing the direction of flight. As was said above it becomes like a giant plank of plywood outside, and your airspeed will rapidly decay. For this reason, most turboprop drivers carry power right until the aircraft is on the ground. Once on the ground the power can come back to flight idle, and into beta/reverse.
In the above report it discusses the logic for the spoiler/GLD devices. One of the conditions being position of the thrust levers. It could have been a contributing factor. The F/O had plenty of time 4000 hrs or so, but only 100 hrs jet. Old habits die hard, and in a moment of inattention your natural reflex takes over.
This is purely my opinion, and nothing more.
BTD
Re: Jazz Hard Landing Report
Small correction:jjj wrote:Also, the report indicates that the Captain put away his camera at 700 AGL and the problems started after that.
When the aircraft was 0.4 nm from
the threshold at 700 feet asl (170 feet above runway elevation), the captain put away his camera.
Re: Jazz Hard Landing Report
I didn't mean for you to remove your entire post, I was just correcting the AGL part.
I find that many TSB reports contain unfortunate red herrings. See the Alberta PA-46 crash for just such an example (overweight).
In this case though, I think it can't be stressed enough, that the captain did not take seriously the experience level of the f/o.
Imho.
I find that many TSB reports contain unfortunate red herrings. See the Alberta PA-46 crash for just such an example (overweight).
In this case though, I think it can't be stressed enough, that the captain did not take seriously the experience level of the f/o.
Imho.
Re: Jazz Hard Landing Report
Thank you for the clarification. I fly PA34 and I am familiar with the fine prop increased drag concept. I was not sure that this is the matter, and the comment realtive to the severity of the 30-50 ft pull power to idle caught my eye.
Thanks.
Thanks.
joco
Re: Jazz Hard Landing Report
Not to play the devil's advocate here, but bringing the power levers to idle on props does not mean you will fall out of the sky all of the time. On the PC-12 I used to approach at ~100 KIAS with 30 flap (about 10 PSI I think) and go to flight idle at 50' or so. Even then you would still float if you had a tailwind or were high. Same goes for the Dash 8-300....if you're heavy and landing with props at 900, pulling the levers to idle does not drop you on the runway, especially if you're a bit fast. One skipper I was with said a fully loaded Dash 8-300 (clean) @ props 900 slows the same way a light RJ does. I haven't flown both so I can't confirm that.
On the other hand, on a King Air 100 landing with full flaps and props full fine, you had better be ready to land when you chop the power near the ground!
EC
On the other hand, on a King Air 100 landing with full flaps and props full fine, you had better be ready to land when you chop the power near the ground!
EC
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Re: Jazz Hard Landing Report
I think "falling out of the sky" with the prop levers at idle on most turboprops has more to do with the loss of slipstream over the wings than anything else. On a PC12 its not as noticeable since its a much lighter a/c and the prop is in the front, not over the wings.
On the RJ, the engines are in the back, so there is no slipstream effect.
On the RJ, the engines are in the back, so there is no slipstream effect.
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Re: Jazz Hard Landing Report
I agree that this is a factor, however, when you pull the power back to idle after touchdown, the same deceleration can be felt that you feel in the air, at least on the Metro (If I recall correctly you used to fly them?). You can also here the "discing" of the props.TopperHarley wrote:I think "falling out of the sky" with the prop levers at idle on most turboprops has more to do with the loss of slipstream over the wings than anything else. On a PC12 its not as noticeable since its a much lighter a/c and the prop is in the front, not over the wings.
On the RJ, the engines are in the back, so there is no slipstream effect.
Yeah I remember the PC-12 would float, even with the power right at idle. Like a big cherokee. I believe it may have to do with how the prop is governed. Never flown a Dash, so I have no idea. But I certainly agree not all aircraft fly the same, and broad generalizations should be avoided. oops.El Comat wrote:Not to play the devil's advocate here, but bringing the power levers to idle on props does not mean you will fall out of the sky all of the time. On the PC-12 I used to approach at ~100 KIAS with 30 flap (about 10 PSI I think) and go to flight idle at 50' or so. Even then you would still float if you had a tailwind or were high. Same goes for the Dash 8-300....if you're heavy and landing with props at 900, pulling the levers to idle does not drop you on the runway, especially if you're a bit fast. One skipper I was with said a fully loaded Dash 8-300 (clean) @ props 900 slows the same way a light RJ does. I haven't flown both so I can't confirm that.
On the other hand, on a King Air 100 landing with full flaps and props full fine, you had better be ready to land when you chop the power near the ground!
EC
Anyway, it was just a hypothesis I had based on the report.
BTD
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Re: Jazz Hard Landing Report
The PC12 engine & prop produces little or no added airflow/ift over the wings, and the PC12 has a long relatively high lift wing.
In other words, when you pull the power on a PC12 you are increasing drag from the prop but not reducing lift. Whereas reducing the power to idle on a King Air or 1900D not only creates drag from prop, it also reduces lift in the form of less airflow over the wing.
In a nutshell pulling the power on a turbo-prop increases drag and in the case of wing mounted engines reduces lift. On a jet the engine continues to produce some thrust even at idle and there is never any loss of lift.
BTD you are somewhat right in regards to the prop governing. The low pitch stop can be adjusted within a certain range, at least on some of the PT6 models.
In other words, when you pull the power on a PC12 you are increasing drag from the prop but not reducing lift. Whereas reducing the power to idle on a King Air or 1900D not only creates drag from prop, it also reduces lift in the form of less airflow over the wing.
In a nutshell pulling the power on a turbo-prop increases drag and in the case of wing mounted engines reduces lift. On a jet the engine continues to produce some thrust even at idle and there is never any loss of lift.
BTD you are somewhat right in regards to the prop governing. The low pitch stop can be adjusted within a certain range, at least on some of the PT6 models.
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Re: Jazz Hard Landing Report
Yeah the metro was like that. If I recall, we used to have a little power on until the flare, 5-10ft, then they came idle. I remember "crushing" a few landings on the metro whenever I brought the levers to idle too early.BTD wrote: I agree that this is a factor, however, when you pull the power back to idle after touchdown, the same deceleration can be felt that you feel in the air, at least on the Metro (If I recall correctly you used to fly them?). You can also here the "discing" of the props.
I find the RJ 705 similar. With the 100/200, you bring the thrust to idle at 50ft and start to flare at about 10ft and you will get fairly consistent landings. On the 705 however, if you use that technique you will crush it on so good that you will want to keep the cockpit door closed until all the pax are off. Ive had a few of those too, including one last week
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Re: Jazz Hard Landing Report
The CVR recording was not released was it?
Why did the report only release info about the camera and nothing else?
Remove the capt's camera from the scenario and explain what might have happened instead.
Why did the report only release info about the camera and nothing else?
Remove the capt's camera from the scenario and explain what might have happened instead.
Re: Jazz Hard Landing Report
It was an aircraft handling problem on landing, just like the Skyservice 767 incident. Unfortunately, both caused significant damage to the aircraft structures. I wonder, was the Skyservice Capt to blame as well even though he was not the pilot flying? This is about the experience level of the pilot flying, company training procedures, and adherence to aircraft handling techniques that are taught during line indoc.