Landing the max

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KAG
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Landing the max

#1 Post by KAG » Mon Mar 05, 2018 11:32 am

Heard through the grapevine you guys may be having a hard time landing the max as youre taught to start reducing the power at 40feet? If that's the case that's wrong and will result in some tail strikes and hard landings. I wouldnt think about reducing power till at least 20 feet (unless you have a 20kt gust correction then 20-30 feet depending on how its feeling) and if your down south even less. Just thought I'd pass along a bit of a tip if this is what you're taught. If not sorry for sticking my noise where it doesn't belong. Enjoy the plane if not the small flight deck :smt040
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rudder
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Re: Landing the max

#2 Post by rudder » Mon Mar 05, 2018 2:15 pm

KAG wrote:
Mon Mar 05, 2018 11:32 am
Heard through the grapevine you guys may be having a hard time landing the max as youre taught to start reducing the power at 40feet? If that's the case that's wrong and will result in some tail strikes and hard landings. I wouldnt think about reducing power till at least 20 feet (unless you have a 20kt gust correction then 20-30 feet depending on how its feeling) and if your down south even less. Just thought I'd pass along a bit of a tip if this is what you're taught. If not sorry for sticking my noise where it doesn't belong. Enjoy the plane if not the small flight deck :smt040
Unless I am mistaken, 737 A/T is certified to touchdown. If operated that way, I believe A/T reduces thrust to idle commencing at 27’ RA.

I cannot think of a single Boeing built where either the FCTM or line trainers would suggest that reducing thrust to idle at 30+ feet would be appropriate.
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Re: Landing the max

#3 Post by altiplano » Mon Mar 05, 2018 3:10 pm

Thanks KAG.
I don't know if some guys are having a hard time landing it, but they aren't training 40' power reduction. Flare is being recommended at approx 20' call, figuring the power reduction per FCTM, slow thrust reduction in flare, reaching idle at approx touchdown.

Rudder.
A/T is only being trained for autolands, unlike the bus or 777/787 where you can manual landing A/T on.
I'm not sure if it's a certification issue, or supplement you have to buy, or an ACism that they are disconnecting A/T for manual flight on the 37.
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Re: Landing the max

#4 Post by tbaylx » Mon Mar 05, 2018 3:19 pm

It's a FCTM recommendation, not a limitation. Sunwing does the same. Not sure bout Westjet
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Re: Landing the max

#5 Post by KAG » Mon Mar 05, 2018 6:10 pm

At off at 50 feet at wj unless autoland.
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Re: Landing the max

#6 Post by rudder » Tue Mar 06, 2018 12:07 pm

Ultimately the A/T protocol is set by each operator via their local FCOM.

Some carriers subscribe to the “click click - click click” philosophy. A/T disconnected when A/P disconnected. Others want A/T off prior to touch down when not conducting auto land. Others permit A/T to touchdown for all landings. Only meaningful difference is the Vref adjustment (half the HW and all of the gust to a max additive of 20kts vs no correction required for A/T).

Still would not suggest the manual thrust reduction to idle for landing above the 20’ callout.
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Re: Landing the max

#7 Post by Commonwealth » Tue Mar 06, 2018 4:51 pm

It's an airplane. Overthinking a landing produces predictable results.
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Re: Landing the max

#8 Post by confusedalot » Tue Mar 06, 2018 7:32 pm

Never flew the max (only the max sim) but I do know that it is not much different than the NG.

FCTM does in fact recommend to disengage the autothrottle while manually flying, but it is not a limitation. For those I have seen elect to keep the A/T on while manually flying, they seem to get into this loop where slightest pitch changes induces the A/T to overcompensate in thrust changes, and vice versa, leading to a somewhat comical final approach pattern.

40 feet is way to high to chop the power in a 737. 20 feet is more like it.
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Re: Landing the max

#9 Post by Go Guns » Tue Mar 06, 2018 8:37 pm

The best way around fighting the auto throttle on a manual approach like that is to deselect speed, put the auto throttle in “arm”. It might add a layer of complexity, but it’ll be easier to get back if you need it (toga), and remains armed for alpha floor protection.
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Re: Landing the max

#10 Post by yycflyguy » Wed Mar 07, 2018 11:23 am

Go Guns wrote:
Tue Mar 06, 2018 8:37 pm
The best way around fighting the auto throttle on a manual approach like that is to deselect speed, put the auto throttle in “arm”. It might add a layer of complexity, but it’ll be easier to get back if you need it (toga), and remains armed for alpha floor protection.
I don't know if some guys are having a hard time landing it, but they aren't training 40' power reduction. Flare is being recommended at approx 20' call, figuring the power reduction per FCTM, slow thrust reduction in flare, reaching idle at approx touchdown.
The combination of the above two posts is the AC SOP... AC loves to complicate things.

Deselecting the Speed Tile for manual landing so A/T armed for a G/A.
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Re: Landing the max

#11 Post by Donald » Wed Mar 07, 2018 11:52 am

What can happen if you leave the A/T engaged, in speed mode:

http://www.bst-tsb.gc.ca/eng/rapports-r ... 2w0004.pdf
The EGPWS radar altitude countdown sounded “... 50, 40, 30, 20, 10” but the captain did not disarm the A/T at 50 feet agl in accordance with standard operating procedures. The aircraft touched down at 134 KIAS, 1800 feet from the threshold with 4602 feet remaining. When the captain moved his hand to actuate the thrust reversers, the A/T advanced the thrust levers in order to maintain the selected speed of 133 knots. This action prevented the extension of the speed brakes. The captain repositioned his hand on the thrust levers and brought them to flight idle while disconnecting the A/T. Contrary to Enerjet standard operating procedures, the first officer did not call out “no speedbrake”, “no reverse”, or “autobrake disarm” during the initial roll-out.
Boeing 737-700 Autothrottle (A/T) System

The A/T system provides automatic thrust control from the start of takeoff through climb, cruise, descent, approach and go–around or landing. In normal operation, the FMC provides the A/T system with engine N1 limit values. The A/T moves the thrust levers with a separate servo motor on each thrust lever. Following manual positioning, the A/T may reposition the thrust levers to comply with computed thrust requirements except while in the THR HLD and ARM modes.

At the time of touchdown, the A/T system was in MCP SPD mode with the AFDS set up for ALT ACQ. This configuration does not allow the A/T system to enter retard mode during the flare as this setup is used for a go around situation. The A/T system will retard thrust levers to idle in single autopilot mode only if the AFDS is in approach mode and the aircraft descends through 27 feet radar altitude.
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Re: Landing the max

#12 Post by yycflyguy » Wed Mar 07, 2018 1:51 pm

Donald wrote:
Wed Mar 07, 2018 11:52 am
What can happen if you leave the A/T engaged, in speed mode:

http://www.bst-tsb.gc.ca/eng/rapports-r ... 2w0004.pdf
The EGPWS radar altitude countdown sounded “... 50, 40, 30, 20, 10” but the captain did not disarm the A/T at 50 feet agl in accordance with standard operating procedures. The aircraft touched down at 134 KIAS, 1800 feet from the threshold with 4602 feet remaining. When the captain moved his hand to actuate the thrust reversers, the A/T advanced the thrust levers in order to maintain the selected speed of 133 knots. This action prevented the extension of the speed brakes. The captain repositioned his hand on the thrust levers and brought them to flight idle while disconnecting the A/T. Contrary to Enerjet standard operating procedures, the first officer did not call out “no speedbrake”, “no reverse”, or “autobrake disarm” during the initial roll-out.
Boeing 737-700 Autothrottle (A/T) System

The A/T system provides automatic thrust control from the start of takeoff through climb, cruise, descent, approach and go–around or landing. In normal operation, the FMC provides the A/T system with engine N1 limit values. The A/T moves the thrust levers with a separate servo motor on each thrust lever. Following manual positioning, the A/T may reposition the thrust levers to comply with computed thrust requirements except while in the THR HLD and ARM modes.

At the time of touchdown, the A/T system was in MCP SPD mode with the AFDS set up for ALT ACQ. This configuration does not allow the A/T system to enter retard mode during the flare as this setup is used for a go around situation. The A/T system will retard thrust levers to idle in single autopilot mode only if the AFDS is in approach mode and the aircraft descends through 27 feet radar altitude.
Good info!

Why Weight on Wheels doesn't automatically trigger A/T Retard is beyond me. "New" airplane. Dumb logic.
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Re: Landing the max

#13 Post by altiplano » Wed Mar 07, 2018 3:44 pm

That's a good one. Lots to learn there... They should have left the FDs off.
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Re: Landing the max

#14 Post by confusedalot » Wed Mar 07, 2018 8:35 pm

Go Guns wrote:
Tue Mar 06, 2018 8:37 pm
The best way around fighting the auto throttle on a manual approach like that is to deselect speed, put the auto throttle in “arm”. It might add a layer of complexity, but it’ll be easier to get back if you need it (toga), and remains armed for alpha floor protection.

Sounds like a good idea. Forgive me for my lapse of memory, it's been a few years since I've flown the plane, but it seems to me that you cannot disengage the speed mode on the MCP since it will be ''locked in'' while the A/T is in use, but you can disengage the A/T either by pushing the throttle switches (or the A/T switch on the MCP), and then re arm the A/T via the MCP?

By doing that though, won't that just automatically re engage the speed mode? Just asking, I forget.

Cheers.
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Re: Landing the max

#15 Post by Go Guns » Wed Mar 07, 2018 9:31 pm

If you were to deselect MCP SPD, then capture the g/s it might re-engage, I would have to double check. Otherwise, once on the sloop, de-select MCP SPD and the auto throttle will revert to ARM. My whole theory assumes you’re not doing an autoland, and plan to disengage the auto throttle before 50’.
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Re: Landing the max

#16 Post by jjj » Fri Mar 09, 2018 1:15 pm

By the time you react to the 30 foot call to close the thrust levers you are roughly mimicking what the plane does in an auto land and are fully compliant with the FCTM.

As far as keeping some power on you'll decide that for yourself as a pilot when you feel the ass fall out of it on occasion.

A bad technique which is all too common at WS is keeping power on until the 10 foot automated prompt then closing power levers. By the time you react - the wheels are on and despite the power lever position - thrust is still way up. It's too many Newtons and a recipe for going off the end one day.

Thank goodness our TLRs have a 15% bias - half the pilots need it.

Enjoy your new airplane AC pilots!!!

Cheers.

JJJ
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Re: Landing the max

#17 Post by cheeky cough » Sat Mar 10, 2018 7:04 am

Thanks for the info everyone. The Max has been fun. Small flight deck, have already banged my head and my knee.
We are interested in all the 737 gotchas that you have experienced in last many years. This airplane needs to be respected in my opinion.
We have not had an airplane in awhile that one has to disconnect the autothrottle. Embraer, Airbus, 787 , etc, can all be left on till it tells you to retard in flare (Airbus)but stay on ,throttles comes back on their own in flare but stay on(Embraer) , 787.777, stays on all the way similar to Embraer.

What I am finding is I tend to get slow, add power and then float a bit, eating up runway. I know the 737-800 and 900 eat up runway and can cause overruns.

The Max has small galleys and is somewhat disliked by backend crews. The aft Lavs are a bit annoying to passengers as the doors open into the galley, not a lot of room. On the positive side is the huge bins, large entertainment screens and the fantastic fuel burns.
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Re: Landing the max

#18 Post by J31 » Sat Mar 10, 2018 9:12 am

If you follow the recommendation from the Boeing 737Max Flight Crew Training Manual (FCTN) you will be rewarded with nice landings. If you get below Ref on touchdown you will be rewarded with a firm and dramatic oleo compression! :oops:

From the Boeing FCTM:

When the threshold passes under the airplane nose and out of sight, shift the visual
sighting point to the far end of the runway. Shifting the visual sighting point assists
in controlling the pitch attitude during the flare. Maintaining a constant airspeed
and descent rate assists in determining the flare point. Initiate the flare when the
main gear is approximately 20 to 30 feet above the runway by increasing pitch
attitude approximately 2° - 3°. This slows the rate of descent.
After the flare is initiated, smoothly retard the thrust levers to idle, and make small
pitch attitude adjustments to maintain the desired descent rate to the runway. A
smooth thrust reduction to idle also assists in controlling the natural nose-down
pitch change associated with thrust reduction. Hold sufficient back pressure on the
control column to keep the pitch attitude constant. A touchdown attitude as
depicted in the figure below is normal with an airspeed of approximately VREF.
Ideally, main gear touchdown should occur simultaneously with thrust levers
reaching idle.
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Re: Landing the max

#19 Post by privateer » Mon Mar 12, 2018 10:25 am

cheeky cough wrote:
Sat Mar 10, 2018 7:04 am
Thanks for the info everyone. The Max has been fun. Small flight deck, have already banged my head and my knee.
We are interested in all the 737 gotchas that you have experienced in last many years. This airplane needs to be respected in my opinion.
We have not had an airplane in awhile that one has to disconnect the autothrottle. Embraer, Airbus, 787 , etc, can all be left on till it tells you to retard in flare (Airbus)but stay on ,throttles comes back on their own in flare but stay on(Embraer) , 787.777, stays on all the way similar to Embraer.

What I am finding is I tend to get slow, add power and then float a bit, eating up runway. I know the 737-800 and 900 eat up runway and can cause overruns.

The Max has small galleys and is somewhat disliked by backend crews. The aft Lavs are a bit annoying to passengers as the doors open into the galley, not a lot of room. On the positive side is the huge bins, large entertainment screens and the fantastic fuel burns.
Don't forget how quiet it is. I was sitting next to the wing a few weeks ago and I could have a really clear conversation with someone next to me. Compared to the bus with all the weird hydraulic sounds its a peaceful bird. Thanks to SW the overhead panel is a little archaic and the plane itself a little narrower but she's a well designed bird.
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Re: Landing the max

#20 Post by Eric Janson » Mon Mar 12, 2018 11:55 pm

yycflyguy wrote:
Wed Mar 07, 2018 1:51 pm
Why Weight on Wheels doesn't automatically trigger A/T Retard is beyond me. "New" airplane. Dumb logic.
That would be to avoid a false signal retarding the thrust levers at an inappropriate time such as in cruise or intercepting the ILS.
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Re: Landing the max

#21 Post by yycflyguy » Wed Mar 14, 2018 9:13 am

Eric Janson wrote:
Mon Mar 12, 2018 11:55 pm
yycflyguy wrote:
Wed Mar 07, 2018 1:51 pm
Why Weight on Wheels doesn't automatically trigger A/T Retard is beyond me. "New" airplane. Dumb logic.
That would be to avoid a false signal retarding the thrust levers at an inappropriate time such as in cruise or intercepting the ILS.
When would you have weight on wheels during cruise or intercepting glideslope?
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Re: Landing the max

#22 Post by Eric Janson » Thu Mar 15, 2018 3:25 pm

yycflyguy wrote:
Wed Mar 14, 2018 9:13 am
Eric Janson wrote:
Mon Mar 12, 2018 11:55 pm
yycflyguy wrote:
Wed Mar 07, 2018 1:51 pm
Why Weight on Wheels doesn't automatically trigger A/T Retard is beyond me. "New" airplane. Dumb logic.
That would be to avoid a false signal retarding the thrust levers at an inappropriate time such as in cruise or intercepting the ILS.
When would you have weight on wheels during cruise or intercepting glideslope?
A/T system works with inputs from various systems. A false Radio Altimeter signal has caused an accident by retarding the thrust levers on the ILS and keeping them at idle while the speed decayed to Vref - 40.

Adding complexity also adds to the failure cases that need to be addressed - in your example it would be a false wow signal with all the consequences. That could come at any point during the flight.

It's far simpler not to have your suggested feature.

Adding complexity is not always the best option.
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Re: Landing the max

#23 Post by yycflyguy » Fri Mar 16, 2018 8:55 am

So you're saying it's safer, compared to the unlikely event of a false radar altimeter reading, that the thrust levers (that you can see physically moving) should never depart from bugged speed than it is to have a microswitch sensing WoW for the thrust?

I would suggest that if a crew allows their energy state to decay to Vref - 40 that maybe Wow sensing is the least of their problem...
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Re: Landing the max

#24 Post by Eric Janson » Fri Mar 16, 2018 3:31 pm

Here's the accident. It's not that unlikely.

https://en.wikipedia.org/wiki/Turkish_A ... light_1951

(Turkish ALPA called the crew 'Heroes' and publicly blamed ATC :roll: :roll: )

The problem was that this failure wasn't in the FCOM and crews were unaware this could happen. I'm sure you'll find a bulletin about this in the current FCOM.

I've had the thrust levers of a 737 go to idle in cruise for no apparent reason.

Can be very confusing when systems don't work as expected - especially with no obvious failures.
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Re: Landing the max

#25 Post by fish4life » Fri Mar 16, 2018 4:25 pm

ummm, is that not a good example of why the working up north is great for teaching you lessons compared to the "European" model? They caught the fact it got slow initially but then what the hell happened?
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