Smooth landings on the 744?

[hihello_21]

How do you grease the landings with the 744? I'm so used to flying the 737, I find it really difficult to land the jumbo smoothly. Usually while flyin the 737, i set thrust to idle at about 50 feet AGL and start to flare at around 30 AGL. I just don't have a clue as to when to start flaring the 744. Sometimes i do it too quickly and the plane stays afloat, over the runway too long before touchdown. Or sometimes i fail to flare and the aircraft lands with a thud and the landing rate comes to somewhere around -600 fpm!!
Need your help on this one.....

And what kind of a landing rate can actually cause physical damage to the airplane?

Pilot No: 2727
Sathya Narayanan

btw, this is my first post on GCVA!

[jcwaugh747]

Answering that question properly would take reams of paper, like a Flight Manual....lol

We will be creating some expanded lessons on subjects like this, but I can briefly say that with the 747 (100, 200, 300, 400 or even 800) there are a few points that are fairly critical.

They are items which you would want to do on ANY airplane, but are especially crucial on the 747.

GREASING IT ON
Believe it or not, the 747 was designed in a fashion where if landed properly, you will NOT grease it on. The landing gear are designed to absorb the weight as the plane transitions from flight to ground mode. This does not mean that you would fly an approach and disregard flaring, it means that they want a flare which will slow the sink rate but not eliminate it where the plane is held just barely off of the ground and settles in a fashion where it is hard to perceive when it actually landed.

Now, in a real 747, if you land with a sink rate of 100 feet per minute, it will feel like it does when you land a Cessna 172 with a 10 feet per minute sink rate, again because of the suspension components of the landing gear.

Even though it would seem to be the opposite, the designers of the plane were concerned with what happens if you were to hold the plane just an inch off of the ground, holding it there until it stalls, like people often do with little airplanes. If you were to do that with a plane like a 747, it would probably collapse the gear and overstress the wing spar.

There are a few different methods used. One common one is to start a flare at 100 feet, pitching up about 2.5 degrees. You only start at 100 feet and hopefully have the 2.5 degrees at 50 feet. You hold that until touching down, NOT trying to hold the plane off of the ground. The Thrust Levers are SLOWLY reatarded at fifty feet.

FLAPS
The one thing I have seen improperly used in the Virtual world, probably more than any other item, is proper flap settings on takeoff and landing. With the 747 you will NOT routinely land with full flaps at Flaps 30. The majority of the time, pilots will use Flaps 25 for landing. The key determination is a combination of available runway length, landing weight and weather. Flaps 30 is not normally used when landing with a crosswind. When we think about 25 or 30 it does not seem to be that big of a difference. When you look at the difference in the area of metal exposed to the wind (DRAG), it is a big deal. Flaps 30 will give you a much higher sink rate because of the drag and will result in a harder landing. Compound that with a gust of crosswind at twenty or thirty feet off of the ground and you have yourself a party…..lol Don't take that wrong. If you need to land at a slower speed or because of obstacles and the wind is not a factor, use all the Flaps you can. Just expect a good firm landing, which will be better for braking anyway.

SPEED
This is something that most pilots (real or virtual) will fail to properly maintain when a bad landing is encountered. If you go too fast, you will float and float and float and did I mention float? If you go too slow there will not be enough energy to trade off sink rate for airspeed and the plane will fall through at the bottom and you will become aircraft carrier qualified.

The ideal approach will account for the wind conditions. This will usually result with starting with a REF speed that is computed for the landing weight. To this you add HALF of the headwind being reported plus ALL of the Gust Spread. The performance data will take into account the added speed for wind and tell you how long of a runway you will need to safely land.

The important thing is to maintain THAT speed…….PERIOD.


So now, throw those things together, along with quite few more factors, and you have the recipe for impressively landing a 747.

One interesting thing to try sometime is to put the plane on Auto LAND and sit back and watch how it flies multiple approaches with the same wind settings but different flap settings, to see how the BRAIN does it.

[jcwaugh747]

BTW,

Welcome to GCVA!!!!

[Bodo Mueller]

Hi John,

I read your comment with interest. However, PMDG did not a very good job on the flight dynamics for the 744 because the aircraft tends to float over the runway very often even speed and flaps are set right. However, this is an limitation or error of FS PMDG did not overcome by reasonable settings to prevent that. The MD-11 has a much better FDE though. I hope that the 744 V2 which is announced after the 777 will be improved in this area.

I did the flight dynamics for the RFP 742 and it doe not have those problems. I tend to say it is easier to land a real 744 than the PMDG in FS.

[jcwaugh747]

Bodo,

Your comments were quite interesting and I agree completely, the RFP 742 does feel a lot closer to the “Real” 747 than the PMDG 744 does, though obviously the PMDG version is leagues ahead of the Microsoft version. I have found that even a few Level D sims in use by some big name airlines are not much better than the PMDG version in that area. A lot of people do not realize the complexities involved in modeling aerodynamics into a simulator when introducing factors such as ground effect. You obviously do, considering the end result of the RFP 742. Good job!

For new pilots starting out, you could learn a lot about the finesse needed to fly a good approach for ANY aircraft which has Auto-Land capability. An easy way to do that is listed below:

1. Load the plane with a fuel/cargo weight which will place it at a typical landing weight (Heavy for Cargo Planes)
and freeze the fuel burn on the sim.
2. Takeoff and fly around the pattern and set up for an extended final for an ILS approach.
3. Somewhere at a point about five or ten miles prior to Glideslope intercept, freeze the sim and save that as a
flight setup. Now you have a place to start any time you want to recreate your training.
4. Let the plane fly the approach on Autoland and sit back and watch, your only interaction should be to extend flaps
and gear.
5. Repeat Step 4 many many times, hopefully noting when and where the auto pilot starts doing things, such as
flare, thrust to idle, etc.

A couple notes here:
1. After you watch the Autopilot a few times, also note the rate at which it does things
like pitch changes or thrust lever changes.
2. The Auto Pilot on FS is not exactly as accurate as a real auto pilot and will cheat to some degree, though it will still give
you a good starting point on understanding the art of flying an approach.

After you get bored with watching the plane auto land and restarting the flight over and over again, simply press that red button on the yoke and go for it.

These above steps are about as close as you can get to sitting in the right seat and watch an experienced pilot fly a good approach, well for right now it is the closest thing……

[Brogs]

Great stuff John , !

[Eugenio Leal/1878]

Great post!

thanx for sharing guys!

[hihello_21]

Thanks guys for the replies and especially John, for your detailed explanation. Yes I tried autoland a couple times and now I can somewhat manage to do better landings.

And during descents I always have to get the speedbrakes up in order to keep the speed in control. For most part of my descent I keep the speedbrakes up. Does this happen in real life too?

[jcwaugh747]

Thanks guys for the replies and especially John, for your detailed explanation. Yes I tried autoland a couple times and now I can somewhat manage to do better landings.

And during descents I always have to get the speedbrakes up in order to keep the speed in control. For most part of my descent I keep the speedbrakes up. Does this happen in real life too?

Actually, the Speed Brakes will generally only be used for times where you get slam dunked by ATC and they want an expedited descent or they want you to slow up quickly.

In the 747 world there is a very common saying, "You can Slow Down or You can Go Down, But You can't Do BOTH!"

In a normal descent, say from 370 or 390, you will just pull the Thrust Levers to idle and descend at a predetermined Target Airspeed. 320 is very common. As you descend, you adjust airspeed with pitch and keep the engines at idle, or program the AutoPilot to 320 knots and you will see the AutoThrottles go to idle.

Now as you are reading this, some people might be saying, "That's crazy, if I pitch for 320 knots on the descent it will take FOREVER to get down and I will blow past the airport!" Well that is very true. That is why you will need to begin your descent a long way from the airport. The exact numbers are something that are a complete lesson, but as a general rule take the altitude you need to loose, (Current Altitude minus Airport Elevation) multiply that times three, then add 40 to that number. In other words you will see that you will be starting your Jumbo Glider descent somewhere in the 95 to 125 mile range from the airport. For the purists, we will be covering a much more indepth lesson on calculating let-down computations which will incorporate distance for slowing,crossing restrictions, and adjustment for straight-in, base, downwind or upwind entries.

Hopefully I have made this explaination at least a little more clear than mud. It is hard to answer a technical question without going too technical. For some of the new folks who might be reading this and wondering what some of the terms we are throwing around, we will be developing a cheat-sheet list of technical terms and expanded lessons which cover anything from "What is an Airfoil" to "Detemining Best Cruise Altitude Based on Winds Aloft"

With all that said, keep in mind that if you are in a descent and the plane is going too fast, pitch the nose up from you have it (slowly and slightly), give it a bit of time to respond. And repeat as necessary.

Most R/W pilots will treat the SpeedBrakes as an "OH SH## Lever"

[Brogs]

Prior to descent, here's a tip I read and found very useful, on the FIX page of the CDU enter the destination Airport e.g EGCC, then on the scratchpad enter /30 and line select that to the Fix line this will give you a 30 mile circle around your destination Airport, then using the Rule of Thumb "3 miles descent = 1000ft" work out the TD distance from the Airport "e.g FL300 ToD 90 mls from Destination," then enter /90 in the S/pad and upload again to Line Select and this will put a 90 mile Circle around your Destination Airport, so now you have 2 Circles around your Dest A/port, now in addition I personally add 20 mls to the 90 and put a further circle around my Dest A/port of 110 mls . When I arrive at that point "110 mls" in the Flight I start prepping for my Descent at the 90 ml point , speed adjustment etc , works for me every time, then just let the Vnav fly the descent while you monitor.

[jcwaugh747]

Prior to descent, here's a tip I read and found very useful, on the FIX page of the CDU enter the destination Airport e.g EGCC, then on the scratchpad enter /30 and line select that to the Fix line this will give you a 30 mile circle around your destination Airport, then using the Rule of Thumb "3 miles descent = 1000ft" work out the TD distance from the Airport "e.g FL300 ToD 90 mls from Destination," then enter /90 in the S/pad and upload again to Line Select and this will put a 90 mile Circle around your Destination Airport, so now you have 2 Circles around your Dest A/port, now in addition I personally add 20 mls to the 90 and put a further circle around my Dest A/port of 110 mls . When I arrive at that point "110 mls" in the Flight I start prepping for my Descent at the 90 ml point , speed adjustment etc , works for me every time, then just let the Vnav fly the descent while you monitor.

Mike,

That is a very useful tip, good information. My response was based on the assumption that they probably were not utilizing VNAV at all.

One thing that is actually a bit funny about this topic, I have seen people come up with a LOT of different ways to compute a Let-Down or Top of Descent point and these methods would employ a LOT of technical factors, however they all nearly always come up with something of 100 to 120 miles, depending on cruise altitude.

Your 3/1 rule with a little fudge factor of about 10 miles is actually very close to all that anyone needs to do. Programming the FMS or FMC for crossing restrictions or STAR's is almost cheating.....lol

[Brogs]

Prior to descent, here's a tip I read and found very useful, on the FIX page of the CDU enter the destination Airport e.g EGCC, then on the scratchpad enter /30 and line select that to the Fix line this will give you a 30 mile circle around your destination Airport, then using the Rule of Thumb "3 miles descent = 1000ft" work out the TD distance from the Airport "e.g FL300 ToD 90 mls from Destination," then enter /90 in the S/pad and upload again to Line Select and this will put a 90 mile Circle around your Destination Airport, so now you have 2 Circles around your Dest A/port, now in addition I personally add 20 mls to the 90 and put a further circle around my Dest A/port of 110 mls . When I arrive at that point "110 mls" in the Flight I start prepping for my Descent at the 90 ml point , speed adjustment etc , works for me every time, then just let the Vnav fly the descent while you monitor.

Mike,

That is a very useful tip, good information. My response was based on the assumption that they probably were not utilizing VNAV at all.

One thing that is actually a bit funny about this topic, I have seen people come up with a LOT of different ways to compute a Let-Down or Top of Descent point and these methods would employ a LOT of technical factors, however they all nearly always come up with something of 100 to 120 miles, depending on cruise altitude.

Your 3/1 rule with a little fudge factor of about 10 miles is actually very close to all that anyone needs to do. Programming the FMS or FMC for crossing restrictions or STAR's is almost cheating.....lol

I think the trick is John not to get bogged down with numbers, gives me a headache , lol

[nwadc10]

I think the trick is John not to get bogged down with numbers, gives me a headache , lol

What if your FMS is inop

[jcwaugh747]

Or worse than that.

What if Auto-Land AND FMS is inop???? Oh My!!! lol

[Brogs]

Or worse than that.

What if Auto-Land AND FMS is inop???? Oh My!!! lol

Don't fly that bird again !