Lots of discussion about this especially with the EK 521 crash (they're calling it an "Incident" at Emirates ::) ).
Here's a video making the rounds of a successfully flown Rejected Landing/Balked Landing flown by JAL at Tokyo Narita.
[youtube]FrlP_P_tMGw[/youtube]
You can see a lot of movement of the ailerons and elavators prior to touchdown. The aircraft skips a few times and the spoilers deploy then they decide to reject the landing.
The procedure is to set a pitch attitude and set maximum thrust. You do not touch gear or flaps. It takes 6-8 seconds for the engines to go from idle to maximum thrust with all the thrust coming in the last few seconds.
You wait until your speed accelerates back to above Vref then you perform a normal go around.
You can see all of this on the video - the target pitch attitude is enough to get the aircraft airborne but the gear stays down and the flaps remain set at full. This will generate a configuration warning in the cockpit (as if there's not enough going on already!).
Once they get enough speed they fly the normal go around (you can see the flaps retracting and the gear coming up).
You can also see just how much performance is available with a light aircraft and maximum thrust.
It all looks scary but it was a correctly flown procedure - having flown into Narita it can get very nasty there with gusty crosswinds and a lot of low level windshear.
It will be interesting to find out what happened with Emirates 521.
Rejected Landing
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David MacRay
- Posts: 1259
- Joined: Wed Jun 03, 2015 3:00 pm
I would like to pretend I know how to work one of those big computerized bastards for a moment..
Shouldn't the gear have gone up once they had enough thrust to raise the nose?
Someone must have calculated the reduced drag is not worth the workload maybe? Or did they actually fly test flights to make that call.
Pretty interesting. We need some of the people that developed the procedure to come answer my inane questions.
Shouldn't the gear have gone up once they had enough thrust to raise the nose?
Someone must have calculated the reduced drag is not worth the workload maybe? Or did they actually fly test flights to make that call.
Pretty interesting. We need some of the people that developed the procedure to come answer my inane questions.
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Nark1
David,
First question, no. You want a positive trend before retracting the gear. A fraction of windshear, i.e. Decreasing performance shear, and that nose up attitude will turn into settling very quickly. (Nose up attitude still an pt you back on the ground).
Another thing to consider, these birds are certified to climb one one engine, let alone two, just after takeoff.
It's all about energy management.
First question, no. You want a positive trend before retracting the gear. A fraction of windshear, i.e. Decreasing performance shear, and that nose up attitude will turn into settling very quickly. (Nose up attitude still an pt you back on the ground).
Another thing to consider, these birds are certified to climb one one engine, let alone two, just after takeoff.
It's all about energy management.
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David MacRay
- Posts: 1259
- Joined: Wed Jun 03, 2015 3:00 pm
Basically it was climbing and did not seem slowed by the gear. And to be honest the point when I was thinking of raising the gear would not really change much.
I was not thinking it should come up when they pulled on the yoke/side stick what ever controls the elevator surface. I was just noting (I played it again) after the nose actually comes up. It then started climbing, then there was still quite a pause before retracting the gear. I counted to around thirteen before the gear started moving.
So I figured you push the thrust handles, pull back on the control and wait until the engines wind up and the nose raises indicating the plane is gaining energy from the thrust and is about to climb.
I was just not going to wait until it was 300 feet up.
I am guessing that since the plane is likely pretty light, presumably having used lots of fuel weight before getting to the destination. They could probably just do one of those modern flight school go arounds, with the gear down the whole trip.
Are they raising the gear just to save fuel by reducing drag on those bug uns? And since you're doing such a high thrust lower speed maneuver it's going to suck back nearly as much, so just leaving the gear out a bit longer is not a big deal?
Let's get me in the sim. Maybe I would take longer to flip that gear handle, since I'm a few months past my yearly 172 hour having done it early this year. Of course that might mean I will do at least a second one doubling my annual time. This year.
I was not thinking it should come up when they pulled on the yoke/side stick what ever controls the elevator surface. I was just noting (I played it again) after the nose actually comes up. It then started climbing, then there was still quite a pause before retracting the gear. I counted to around thirteen before the gear started moving.
So I figured you push the thrust handles, pull back on the control and wait until the engines wind up and the nose raises indicating the plane is gaining energy from the thrust and is about to climb.
I was just not going to wait until it was 300 feet up.
I am guessing that since the plane is likely pretty light, presumably having used lots of fuel weight before getting to the destination. They could probably just do one of those modern flight school go arounds, with the gear down the whole trip.
Are they raising the gear just to save fuel by reducing drag on those bug uns? And since you're doing such a high thrust lower speed maneuver it's going to suck back nearly as much, so just leaving the gear out a bit longer is not a big deal?
Let's get me in the sim. Maybe I would take longer to flip that gear handle, since I'm a few months past my yearly 172 hour having done it early this year. Of course that might mean I will do at least a second one doubling my annual time. This year.
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Eric Janson
- Posts: 412
- Joined: Tue Jul 14, 2015 10:31 am
[quote author=David MacRay link=topic=3984.msg10636#msg10636 date=1471626219]
Shouldn't the gear have gone up once they had enough thrust to raise the nose?
[/quote]
The first priority is to fly the aircraft - no matter what you fly.
Rejected landing is a very high workload situation with a lot going on.
After getting the aircraft climbing they needed to retract the flaps from the full setting back to the go-around setting and only then select the gear up.
A number of things need to happen before you see the gear move - doors need to open and the bogies need to be tilted so they fit into the wheel well. Opening the doors will temporarily increase drag.
Nice video of the process - slower than in reality.
[youtube]
b93ekEpTZ-w[/youtube]
On a personal note - I've forgotten to retract the gear on a go-around in the Simulator. Scenario was that the slats/flaps jammed as we intercepted the ILS glideslope. We had to make a go-around and comnplete the checklists. In this scenario you have to manually set the speed otherwise the aircraft will exceed the flap limit speed. First Officer was flying and had no clue what was going on so I was telling him what to do. My workload became so high monitoring him that I forgot to retract the gear.
Shouldn't the gear have gone up once they had enough thrust to raise the nose?
[/quote]
The first priority is to fly the aircraft - no matter what you fly.
Rejected landing is a very high workload situation with a lot going on.
After getting the aircraft climbing they needed to retract the flaps from the full setting back to the go-around setting and only then select the gear up.
A number of things need to happen before you see the gear move - doors need to open and the bogies need to be tilted so they fit into the wheel well. Opening the doors will temporarily increase drag.
Nice video of the process - slower than in reality.
[youtube]
b93ekEpTZ-w[/youtube]
On a personal note - I've forgotten to retract the gear on a go-around in the Simulator. Scenario was that the slats/flaps jammed as we intercepted the ILS glideslope. We had to make a go-around and comnplete the checklists. In this scenario you have to manually set the speed otherwise the aircraft will exceed the flap limit speed. First Officer was flying and had no clue what was going on so I was telling him what to do. My workload became so high monitoring him that I forgot to retract the gear.
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David MacRay
- Posts: 1259
- Joined: Wed Jun 03, 2015 3:00 pm
Cool. Thanks for responding. I blew the question out of proportion too. I just became curious. Seems like in conversations about go arounds in light twins (which I also have zero time in :p ) there has been mention of getting the gear up to reduce drag right away.
It is certainly interesting to me how procedures differ.
Excellent videos!
It is certainly interesting to me how procedures differ.
Excellent videos!
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Eric Janson
- Posts: 412
- Joined: Tue Jul 14, 2015 10:31 am
No problem David - feel free to ask questions.
That's what these Forums are all about imho.
That's what these Forums are all about imho.
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Liquid Charlie
- Posts: 524
- Joined: Sun Aug 23, 2015 1:34 pm
[quote][font=Verdana][size=12px]My workload became so high monitoring him that I forgot to retract the gear[/size][/font][/quote] -- no trigger words coming out of his mouth the gear will be forgotten more than not.
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David MacRay
- Posts: 1259
- Joined: Wed Jun 03, 2015 3:00 pm
I'm bumping this one for a few reasons.
[list]
[li]I'd like to see if we will generate more discussion in relation to the Emerits report.[/li]
[li]That thread is putting this one into a bit better perspective for me as a guy who could learn some good things.[/li]
[li]I think it's a good topic.[/li][/list]
[list]
[li]I'd like to see if we will generate more discussion in relation to the Emerits report.[/li]
[li]That thread is putting this one into a bit better perspective for me as a guy who could learn some good things.[/li]
[li]I think it's a good topic.[/li][/list]
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