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Pineapple_Wizard

Landing the 777, what's going on?

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So recently I've found a rather strange and annoying issue when landing the 777, both the 200LR and 300ER. This is in P3Dv4.1 777 version 1.10.8448. So I fly most approaches manually but with the autothrottle engaged. Upon touchdown, it seems that sometimes the airplane doesn't quite register it is on the ground. I hear the speedbrakes coming up, but the PFD speedtape glitches between NO VSPD and how it normally is during flight. At this point the nose is still up and the aircraft is not decelerating even though the throttles have come to idle. I also cannot seem to activate the reversers either. Autobrakes were set at 2 and still no deceleration. It wasn't until I forced the nose down that I heard the touchdown sounds and the reversers deploy. I've also seen this happen to twitch streamers before while landing the 777. In the options I also have A/T override in flare enabled. For some reason, replicating this issue is difficult, it usually happens during a normal flight, as today it happened upon landing at EHAM from KSFO. Now if I just load in the 777 on a runway, takeoff just as is, fly a pattern, and land manually, everything works as it should. I also use FSUIPC but only for autosave and do not have any controls mapped with it. Any help is greatly appreciated. -Thomas Swehla

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Hi Thomas. It sounds like you are coming in hot, slow down.  In normal conditions the 777 is landed with A/T engaged but you set the speed on the MCP.  Be sure you are stabilized at Vref+5 by 1000 AGL and don't overflare in your landing.  The A/T will retard the throttles around 30 AGL and it takes a few moments for those huge fans to spin down and there is some intentional delay to accommodate a go around before the flare. This delay is what the override in flare addresses (Intro pg 92).  It is normal to use reverse thrust after the mains are on the ground with the nose still in the air, you might have to hit F1 before  F2.

What are you using for throttle control?


Dan Downs KCRP

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Yeah I usually approach at Vref+5, stabilized by 1000', I try to follow the FCOM I have. The flight into AMS was 152 kts on final with the autothrottle. It idled at 30ft like it usually does but on touchdown the plane seems confused, I can't the reversers open until the nose wheel comes down. Also worth pointing out that it does not decelerate at all. You could literally go to the end of the runway still at 150 kts with the nose up. I haven't been able to check the exterior view often when this happens, but the one time I did, the spoilers couldn't decide if they were extended or retracted and the main gear was bouncing a bit. These even happens with hard landings. For throttle control I use a Logitech Extreme 3D pro. It is rather old and there may be some noise on the throttle axis but I don't know if that would affect it.

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Full name on all posts here please Thomas.... PMDG rules.

Noise from the throttle is a problem. Sounds like your autobraking is being cancelled too because she will stop without reverse thrust, just further down the runway.  Reverse thrust is most effective at high speeds, so try hitting F1 before hitting F2 to see if that works.  How does your controller handle reverse thrust?  My Thrustmaster Warthog has throttle levers that lift over a gate and move into reverse thrust, but there isn't a reverse thrust axis.  The gate is actually a switch and I have that programmed in FSUIPC to send an F1 then F2 repeatedly.

The 777 is very easy to land... you might have a problem with configuration?


Dan Downs KCRP

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Try landing at a default airport to rule out scenery layering problems. To me it sounds that it might be the case. If you land at a default aiport and the plane behaves normally, you have isolated the problem to scenery install, flattening and layering.

 

Good luck..


Xander Koote

All round aviation geek

1st Officer Boeing 777

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Okay I'll have a look at trying F1 before F2. As far as my controller, it just goes down to zero, in others words it does not handle reverse thrust.  Whenever I land I just tap F2 to get into reverse. Thomas Swehla

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4 hours ago, Pineapple_Wizard said:

Okay I'll have a look at trying F1 before F2. As far as my controller, it just goes down to zero, in others words it does not handle reverse thrust. 

Can you set the throttle position arrows to show on the N1 EICAS display and then see what the throttles are actually doing as you are landing?  That might help isolate the problem.

Mike


 

                    bUmq4nJ.jpg?2

 

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Rule of the thumb is that u disconnect A/P, then also u should do the same with A/T and vice versa.

Watching real movies on YT, i see that pilots do exactly like that.  


Artur 

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9 minutes ago, Beardyman said:

Rule of the thumb is that u disconnect A/P, then also u should do the same with A/T and vice versa.

...but not on the FBW aircraft like the 777 and 787, where Boeing SOP is to keep the A/T engaged in both automatic and manual flight.

I can only think of one operator that requires the 777 A/T to be disconnected in manual flight; I can think of several (including some big ones) which say it must not be disconnected in normal ops. Where discretion is permitted some pilots may choose to do so but it is not the standard way of operating the aircraft that Boeing intended. 

This is different to the older aircraft with a thrust/pitch couple.

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On 1/4/2018 at 5:34 PM, xkoote said:

Try landing at a default airport to rule out scenery layering problems. To me it sounds that it might be the case. If you land at a default aiport and the plane behaves normally, you have isolated the problem to scenery install, flattening and layering.

 

Good luck..

It's strange I've had the issue at Flytampa AMS before and I've also had no issues there. Today I landed at T2G LFPG and had no issues. Strange, I'll try to record my landings and post a video of when it goes wrong. Thomas Swehla

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I've had the same problem as the OP since I upgraded to the B773.  It doesn't matter if it is Autoland, autothrottle only, or all manual.  It seems more related to the nose not wanting to come down.

blaustern


I Earned My Spurs in Vietnam

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On 1/5/2018 at 4:53 AM, skelsey said:

...but not on the FBW aircraft like the 777 and 787, where Boeing SOP is to keep the A/T engaged in both automatic and manual flight.

I can only think of one operator that requires the 777 A/T to be disconnected in manual flight; I can think of several (including some big ones) which say it must not be disconnected in normal ops. Where discretion is permitted some pilots may choose to do so but it is not the standard way of operating the aircraft that Boeing intended. 

This is different to the older aircraft with a thrust/pitch couple.

Wasn't confusion on this issue the cause of the Air Asiana crash in KSFO?


Vic green

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10 minutes ago, PATCO LCH said:

Wasn't confusion on this issue the cause of the Air Asiana crash in KSFO?

Not really; the issue there was more that the AFDS was in an entirely inappropriate mode (FLCH) for the phase of flight and, on top of that, the flight directors were not being followed in manual flight.

FLCH is a speed-on-pitch mode with fixed (in the case of a descent, idle (generally)) thrust, so if you don't follow the FD pitch commands Bad Things happen, like not achieving the target speed.

Better FMA awareness and more active monitoring in general should have caught the situation.

51 minutes ago, Bluestar said:

It seems more related to the nose not wanting to come down.

I'm not a B777 expert but I do have access to some manuals and I do recall reading a note to the effect that the B777 exhibits neutral pitch stability and therefore certainly on a touch and go the nose requires actively flying down with forward pressure. On a normal landing however I would have expected the pitch-down effect of braking/reverse etc to assist in bringing the nose down somewhat, but I'm not sure.

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Gentlemen, the FCTM has a chapter on landing with pages of information including charts. Do your homework.

Landing Roll FCTM 6.26 "Fly the nose whells smoothly onto the runway without delay.  Control column movement forward of neutral should not be required." If you require forward movement of control column to plant the nose gear then I suspect your flare angle and/or speeds are incorrect.

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Dan Downs KCRP

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Regarding Asiana, as I recall, they were too high and decided to use FLCH to go down more quickly.  However they had already set the go-around altitude, which they were below.  So the throttles increased and the aircraft tried to climb (VNAV doesn't do this if the aircraft is more than 300 ft below go-around altitude -- VNAV will continue to follow the descent path).  So they manually forced the throttles to idle, which put the autothrottles in HOLD (I have been unable to get a PMDG 777 to simulate this, but it is a weird situation not normally encountered).  I believe they switched off the autopilot at this point, but the throttles remained in HOLD.  They did not realize this, and failed to pay attention to the airspeed, presumably because they assumed the autothrottles would maintain approach speed.

Regarding the problem of no autobrakes or reverse thrust until the nose wheel comes down, I have never experienced it, but I am using FSX (Steam).  I wonder if this is only a P3D issue?

Mike


 

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