kmanning

Manual Does not Cover This Procedure

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Posted (edited)

For this version of the 747, there is a procedure NOT covered in detail in any of the manuals. The procedure I'm referring to has to do with landing the 747 with the autopilot and autothrottle disconnected, and none of the manuals DO NOT make reference as to the procedure of when to reduce power to idle and WHEN to initiate the flare. This is the procedure used by pilots in most all landings, and I find it hard to understand why that procedure is not covered in ANY of the manuals. In the tutorial manual, it only discusses landing the 747 in the Auto-Land configuration. In the Flight Crew Operations Manual, there's NO mentioning regarding the procedure of when to reduce power to idle and when to initiate the flare when landing a 747. So, when landing a 747 with the auto-pilot and auto-throttles disconnect, WHEN or at WHAT Altitude do you reduce power to idle, and at WHAT RATE, and precisely WHEN or at WHAT Altitude do you initiate the flare? In the FCOM, all it says is: "If suitable visual reference is esablished at MDA, or DA, or the missed approach point, disengage the autopilot and autothrottle. Maintain the glide path to landing," then goes into another subject, leaving out much more information that's needed. There's more procedures that follow than just maintaining a glide path down to landing. If a pilot just uses the autoland system to land the 747, he's not getting any pratical experience in landing a 747.

The other thing I found differently about landing this version of the 747 is that it will NOT settle onto the runway, even when the power has been reduced to idle. It floats forever before it finally settles down onto the runway. And no, I'm not landing too fast, as I'm using the Vref speeds + 5 knots. So why is this version of the 747's landing characteristics different from the other PMDG 747? But I assume this version more closely memics the real one than the other versions.

Ken Manning

Edited by kmanning
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I assume this is a procedure that would be covered in flight crew training rather than appear in a manual. When you think about it, at that point of the landing phase, everything is happening so fast that you wouldn't be able to go off of a checklist to perform those actions in a timely manner. Also, I would think when you cut power and flare would ultimately be situation dependent. On a good day, you might cut it at 30 feet, but if the winds were to be quite powerful, you might cut the power closer to the ground. I don't know, I'm just making stuff up here.

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Hello,

5 hours ago, kmanning said:

In the Flight Crew Operations Manual, there's NO mentioning regarding the procedure of when to reduce power to idle and when to initiate the flare when landing a 747.

That's because you're looking in the wrong book. FCTM section 6, specifically 6.8 onward, has a great deal of information about landing technique.

Unfortunately, PMDG don't supply a copy of the FCTM, so here's one I wrote earlier: 

 

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15 hours ago, kmanning said:

. It floats forever before it finally settles down onto the runway. And no, I'm not landing too fast,

Perhaps you are over flaring? Most likely you are holding Vref+5 and not allowing speed to decay.  Remember, the aircraft is still flying at Vref+5 and you need to bleed the speed to keep from "floating."  Keep working on it, she is a very easy aircraft to land once you get used to your height above runway.

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2 hours ago, downscc said:

she is a very easy aircraft to land once you get used to your height above runway.

Could not agree more, Dan. Have not swapped to any other aircraft since I bought this.Everything about it is so immersive, a pleasure to fly, even prepping for a flight.

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Ken,

For a B744 manual landing in calm conditions you should always use Flap 25 and a target speed of Vref 25+5 (use Flap 30 if the runway is limiting). Ignore all visual aids below 300ft RA except for the PAPI's and ILS LOC/GS indications and keep the VSI, altimeters and airspeed in your scan down to the flare.  Your aiming point should be approx 1900ft into the runway and if you are misaligned laterally below 200ft RA then go around. At 100ft RA the aircraft nose should be very near the threshold and it MUST be over it by 50ft RA otherwise go around.  Start the flare at 30ft RA by raising the nose 2 degrees and then smoothly close the thrust levers.  Hold the attitude allowing the aircraft to sink onto the runway and adjust the back pressure as necessary so that the nose gear makes contact without delay to ensure maximum braking effort is available.  The Speedbrakes will deploy on mainwheel touchdown if you have armed them and then all you have to do is apply reverse and keep the aircraft on the centerline using rudder and differential brake if required (note: this braking will disconnect the autobrake).  Nosewheel steering should not normally be used until you are at a safe taxy speed (i.e. <20kts). 

As you have found, the landing can go wrong, especially if you raise the nose too high or allow the approach speed to exceed VRef 25 +15 kts.  The aircraft will float and quickly eat up the runway, so it is important to judge the correct nose up attitude every time; primarily by looking down the runway and keeping the wings level using the outside picture and glareshield as a guide.  If the NU pitch attitude exceeds 10 degrees during the flare then the aft fuselage will definitely make contact with the runway -  assuming you are still over it at the time  :-) !!

Happy (manual) landings,

Bertie Goddard

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Posted (edited)

Oddly enough, just completed a manual landing(no AP, no A/T), just bled speed to 5000', then via Flaps 25-30 with speed down to 153kts, followed the FD cross-hairs and landed 24R EGCC without any 'floating', etc. This aircraft is simply a joy to hand-fly an approach.

Edited by vc10man
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Posted (edited)

I don't find it hard to land at all.  In fact it's too easy.  I think like any aircraft, it will float if you are fast or high and unable to correct this over the threshold.  It seems best to me, depending on weight, to kill the throttle at 50 feet AGL and pull back.  If I try to land more like I do in the NGX I land more flat and don't flare enough.  My NGX landings are almost always textbook.  I've had some weird landings in the QOTSII a couple times.  A look outside during replay revealed the nose just wasn't high enough on touchdown. 

It's been ages since I flew the original 744 in FS9 but I seem to remember it landing better, if that makes sense.  I also dislike how the QOTSII will tip over if you hold aileron into the wind.  Seems really bizarre. 

ETA: To clarify the tip over comment.  I landed at SFO with a crosswind.  Mostly center-line and wind from the left.  I held the yoke left, not extreme pressure either.  Next thing I see is the bird tilting.  I'm like "what the....".  Pop outside and the right mains are off the ground and the left wing is headed to the ground.  I don't see how that's possible IRL.

Edited by Orlaam
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Hi,

I have a question to real airliner pilots regarding the flare and landing.

First I bet there may be some difference regarding the landing technic between a GA and an airliner.

I'm having lessons for the PPL in real and at the landing I sometimes flare too much which makes the aircraft climb back a little. My reflex is therefore to release the yoke a little but my instructor tells me that it is a wrong action because it may lead to a rough landing. He "forces" me to maintain the yoke, let the aircraft descent back as the speed bleeds off and then flare again progressively. I believe he is right because applying that technic the landing is soft. The only issue is that the landing distance is increased (which could mean a balked landing is the runway is too short).

In an airliner, if the aircraft climbs back a little during the flare maybe because the pilot pulled the yoke back a little to much, is the technic also to maintain the yoke not matter what until the aircraft descends back again (and eventually do a balked landing if you run down too much runway length) or to release the yoke a little and pull back again in an attempt not increase the landing distance too much?

The question is maybe wrongly phrased but English is not my native language and I hope it is clear.

Off course, the goal is not to flare too much at the first place, but sometimes in down draft, the aircraft may increase its down rate and it is not always easy as a non-professional airliner pilot to pull just the right amount of yoke with the fear of a rought landing.

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Posted (edited)

Great news, Romain, to read that you are going for your PPL. Good Luck. A very interesting post. Well worth looking out for the answers from R/W airliner captains.

Edited by vc10man
spelling mistake
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10 hours ago, Orlaam said:

I don't find it hard to land at all.  In fact it's too easy.  I think like any aircraft, it will float if you are fast or high and unable to correct this over the threshold.  It seems best to me, depending on weight, to kill the throttle at 50 feet AGL and pull back.  If I try to land more like I do in the NGX I land more flat and don't flare enough.  My NGX landings are almost always textbook.  I've had some weird landings in the QOTSII a couple times.  A look outside during replay revealed the nose just wasn't high enough on touchdown. 

It's been ages since I flew the original 744 in FS9 but I seem to remember it landing better, if that makes sense.  I also dislike how the QOTSII will tip over if you hold aileron into the wind.  Seems really bizarre. 

ETA: To clarify the tip over comment.  I landed at SFO with a crosswind.  Mostly center-line and wind from the left.  I held the yoke left, not extreme pressure either.  Next thing I see is the bird tilting.  I'm like "what the....".  Pop outside and the right mains are off the ground and the left wing is headed to the ground.  I don't see how that's possible IRL.

I don't have any trouble landing 747v3 either, but I don't agree that it's too easy. I never found landing a 744 FFS difficult at all. Of course that isn't necessarily exactly the same as the real thing but it is close.

i don't know why you expect it to land like the NGX.

I haven't encountered the tipping issue you mention, but I haven't had to deal with a strong crosswind yet. Obviously it is possible for the aircraft to tilt, which is why you would use into wind aileron. You may have put too much wheel in without realising and pushed the sim into an area where the ground handling model isn't that realistic. Bear in mind the aircraft is still partially flying so what appears to be impossible could actually be possible 

When you say "the right mains" do you mean the wing gear, or both wing and body gear? 

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I've read comments from line pilots here regarding the proper cross wind landing technique and I do not remember any of them referring to the raising the downwind wing.  Sure, it's how it is done in light GA aircraft and as Romain will soon learn the technique becomes automatic without thinking about it thanks to training and repetition.  However, this is done after kicking crab out for the sole purpose of not drifting downwind across the runway.  In a large aircraft I don't think the same applies. Kick the crab out during rotation and land with wings level, or even in some types land in a crab and let the mains take the sideways forces and straighten you out.  One of the most spectacular cross wind landing is performed by the B-52 which has mains that rotate to allow the crab after touchdown, it is really something to see.

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37 minutes ago, downscc said:

One of the most spectacular cross wind landing is performed by the B-52 which has mains that rotate to allow the crab after touchdown, it is really something to see.

Hi, Dan. Now that would be worth really watching. Is there a link to it, Dan? Those are some big beasts to land. I never tired of watching them at an RAF base.

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49 minutes ago, downscc said:

However, this is done after kicking crab out for the sole purpose of not drifting downwind across the runway.  In a large aircraft I don't think the same applies. Kick the crab out during rotation and land with wings level, or even in some types land in a crab and let the mains take the sideways forces and straighten you out.

You are quite correct in that the recommended crosswind technique for the B747 is to de-crab and land wings level (Boeing say you can sideslip (i.e. land "wing down"), but it is not recommended because of the high risk of scraping an outboard pod if you are over-zealous with the bank angle).

However, to state the obvious -- as you squeeze off the crab with rudder you will need some in-to-wind aileron in order to hold the wings level and thus you will touch down with crossed controls. If you do not, the roll-yaw coupling is quite powerful on the B747 and the aeroplane will roll quite sharply in the direction of yaw -- not good!

In-to-wind aileron (proportionate with speed, i.e. increasing slightly as the speed reduces, and proportionate to the amount of crosswind) will then be required during the rollout to ensure the upwind wing does not lift. Indeed, the FCTM says:

Quote

proper rudder and upwind aileron must be applied after touchdown to ensure directional control is maintained.

(my emphasis).

Watching Youtube videos of B747 landings it does seem quite normal for in-to-wind aileron (indeed, up to full deflection as the speed reduces) to be maintained during the landing roll. Of course, when landing there are no concerns around spoiler deployment compared to the crosswind takeoff situation where (as with any aircraft equipped with roll spoilers) the use of in-to-wind control wheel input must be kept to the minimum possible in order to avoid the drag associated with roll spoiler deployment.

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Posted (edited)

9 hours ago, Budbud said:

le. My reflex is therefore to release the yoke a little but my instructor tells me that it is a wrong action because it may lead to a rough landing. He "forces" me to maintain the yoke, let the aircraft descent back as the speed bleeds off and then flare again progressively. I believe he is right because applying that technic the landing is soft. The only issue is that the landing distance is increased (which could mean a balked landing is the runway is too short).

In an airliner, if the aircraft climbs back a little during the flare maybe because the pilot pulled the yoke back a little to much, is the technic also to maintain the yoke not matter what until the aircraft descends back again (and eventually do a balked landing if you run down too much runway length) or to release the yoke a little and pull back again in an attempt not increase the landing distance too much?

Hi Romain,

I suspect what your instructor is concerned about is the situation where you arrive slightly fast, over-flare, balloon slightly, then try to correct by lowering the nose - and if you're not careful the worse-case outcome is that you end up burying it on the nosewheel, something which has happened in the past on aircraft of all sizes and no doubt will continue to happen.

In general I would apply the same technique for a slight balloon as is recommended for a 'light' bounce -- which is to hold and/or re-establish the correct landing attitude. This invariably will require continued, if not fractionally increased, backpressure as the speed reduces. The two things you do not want to do are 1) raise the nose even more and risk a tailstrike (in a long-bodied aircraft - not so applicable to a C172 or a Warrior!), or 2) allow the nose to drop, a high rate of descent to develop and/or the pitch attitude to reduce to the point at which a nosewheel landing results.

Good luck with the PPL -- it should be interesting to hear the views of the airline guys here on this though!

Edit to add: of course, if the float is excessive and you are not going to make the touchdown zone then a go-around remains an option, all the way up to the point at which reverse is selected.

Edited by skelsey
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