Sign in to follow this  
HighFlyer310

Landing Dynamics

Recommended Posts

I wanted to start a discussion (if there is one) on the landing dynamics of the 744. 

I feel like there may be an issue with the way the lateral axis behaves on landing.  Once the mains are down and the boards come open, it should be necessary to counteract the reduction in lift by adding back pressure on the control column.  In the sim, the nose just sort of wants to hang in the air on touchdown, no amount of back pressure is needed to keep the nose from slamming to the ground.  This may very well be an issue with my Saitek Yoke (not that impressed with it); or the way my controls are calibrated (details below).  Just wanted to put this out there to see if anybody else is experiencing the same.  

Saitek Yoke (paired with X52 Pro throttle)

CH Pro Pedals

FSUIPC controls X52 Pro throttle, all other controls calibrated within FSX (roll/pitch control sensitivity reduced by 1/4).

Tom 

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

47 minutes ago, HighFlyer310 said:

I feel like there may be an issue with the way the lateral axis behaves on landing.  Once the mains are down and the boards come open, it should be necessary to counteract the reduction in lift by adding back pressure on the control column.  In the sim, the nose just sort of wants to hang in the air on touchdown, no amount of back pressure is needed to keep the nose from slamming to the ground.  This may very well be an issue with my Saitek Yoke (not that impressed with it); or the way my controls are calibrated (details below).  Just wanted to put this out there to see if anybody else is experiencing the same.  

Speaking theoretically, or from experience?

Do keep in mind that a 172 is not a 747; and that we have a number of 747 drivers on our Tech Team who have specifically provided us details on the quirks of the aircraft.

Share this post


Link to post
Share on other sites

Tom

The QOTS v3 is handling very much like the real aircraft and I use a Saitek Proflight Yoke, pedals etc.  You don't say which Simulator you are using, but no matter which one I suggest you stick to the settings recommended for it by PMDG. 

There are two very good books which you might find interesting reading, because they both describe in great detail the handling characteristics of large jet aircraft like the B744. One is called "Handling the Big Jets" by D.P. Davies and the other is "Flying the Big Jets" by Stanley Stewart.  The first is more technical and slightly outdated now, but it is still considered to be essential reading for would-be professional pilots because it was written by a former test pilot who approved the certification of numerous jet aircraft for the UK civilian authorities, including the original B747. 

The second book describes in more detail a typical flight in a B747 from a pilot's perspective.  In his book, Capt Stewart describes " On touch-down the wheels spin up with a puff of smoke and immediately the autobrakes ....operate to slow the aircraft down. The Captain gently eases the column forward to lower the nose wheel while keeping the wings level with aileron"   It's probably worth bearing in mind that even today real airline simulators have limitations and cannot exactly match the flight characterisitcs and feel of the real aircraft, but with the vast majority being classed as Zero Flight Time they are getting pretty close. However, for most pilots the psychological difference between the simulator and the real aeroplane is unbridgeable.  You can't do any damage or get hurt if you don't flare correctly and crash it, so I suggest you just enjoy flying your PMDG 744 and (like me) marvel at what PMDG have actually achieved with this fine aircraft. It is not perfect but I wouldn't be at all surprised to see some further improvements and added features; especially in the 64Bit P3Dv4 version.

Bertie Goddard   

 

Share this post


Link to post
Share on other sites
1 hour ago, scandinavian13 said:

Speaking theoretically, or from experience?

Do keep in mind that a 172 is not a 747; and that we have a number of 747 drivers on our Tech Team who have specifically provided us details on the quirks of the aircraft.

I understand all that Kyle.  Not everybody in here is a 14 year old waving around his/her youtube knowledge base.  

I do have a good deal of experience in aviation and plenty of contact with flight crews on a day to day basis.  I spoke with an ex Kalitta 744 pilot the other day regarding this and he definitely confirmed that the nose needs to be eased down on landing in most situations.  Anyway, nowhere in my post did I state that my thinking was factual or confirmed.  I just wanted to find out if everyone else was experiencing the same landing characteristics.  

 

1 hour ago, berts said:

Tom

The QOTS v3 is handling very much like the real aircraft and I use a Saitek Proflight Yoke, pedals etc.  You don't say which Simulator you are using, but no matter which one I suggest you stick to the settings recommended for it by PMDG. 

There are two very good books which you might find interesting reading, because they both describe in great detail the handling characteristics of large jet aircraft like the B744. One is called "Handling the Big Jets" by D.P. Davies and the other is "Flying the Big Jets" by Stanley Stewart.  The first is more technical and slightly outdated now, but it is still considered to be essential reading for would-be professional pilots because it was written by a former test pilot who approved the certification of numerous jet aircraft for the UK civilian authorities, including the original B747. 

The second book describes in more detail a typical flight in a B747 from a pilot's perspective.  In his book, Capt Stewart describes " On touch-down the wheels spin up with a puff of smoke and immediately the autobrakes ....operate to slow the aircraft down. The Captain gently eases the column forward to lower the nose wheel while keeping the wings level with aileron"   It's probably worth bearing in mind that even today real airline simulators have limitations and cannot exactly match the flight characterisitcs and feel of the real aircraft, but with the vast majority being classed as Zero Flight Time they are getting pretty close. However, for most pilots the psychological difference between the simulator and the real aeroplane is unbridgeable.  You can't do any damage or get hurt if you don't flare correctly and crash it, so I suggest you just enjoy flying your PMDG 744 and (like me) marvel at what PMDG have actually achieved with this fine aircraft. It is not perfect but I wouldn't be at all surprised to see some further improvements and added features; especially in the 64Bit P3Dv4 version.

Bertie Goddard   

 

Thanks for the input Bertie!

     

 

  • Upvote 1

Share this post


Link to post
Share on other sites
6 minutes ago, HighFlyer310 said:

I understand all that Kyle.  Not everybody in here is a 14 year old waving around his/her youtube knowledge base. 

Mind pointing to where I told you that you were 14, and waving around your YouTube knowledge? Okay, good, because I didn't say that.

Your avatar, however, is clearly a Skychicken (yes, I still fly them, and yes I still call them this), and you wouldn't be first person to walz in and call foul when there is no foul, based off of little plane logic. I know this. I did it all the time years back.

8 minutes ago, HighFlyer310 said:

Anyway, nowhere in my post did I state that my thinking was factual or confirmed.

You said that there may be an issue, ergo you were calling something into question, while using the word 'should'. The word 'should' in this context means that you're asserting this as fact. I simply requested that you back your claim up. Clearly, as you clarified after I questioned your assertion, you had some sort of anecdotal evidence to back your belief up, so why you didn't put this out there at the outset is somewhat baffling.

No need to jump onto the defensive if people don't just come back with "yeah, you're totally right." I asked for your line of logic. That's it. All it requires is providing it. Example: "I'm basing it off of my [insert misinterpreted Kalitta story here.]" Note the lack of snark in the story.

Share this post


Link to post
Share on other sites

Tom...a thread started in Feb that has some credible info and sources chime in...eventually...may have some useful info in the event you wish to explore further the landing characteristics of the 74.

Share this post


Link to post
Share on other sites
12 hours ago, scandinavian13 said:

Mind pointing to where I told you that you were 14, and waving around your YouTube knowledge? Okay, good, because I didn't say that.

Your avatar, however, is clearly a Skychicken (yes, I still fly them, and yes I still call them this), and you wouldn't be first person to walz in and call foul when there is no foul, based off of little plane logic. I know this. I did it all the time years back.

You said that there may be an issue, ergo you were calling something into question, while using the word 'should'. The word 'should' in this context means that you're asserting this as fact. I simply requested that you back your claim up. Clearly, as you clarified after I questioned your assertion, you had some sort of anecdotal evidence to back your belief up, so why you didn't put this out there at the outset is somewhat baffling.

No need to jump onto the defensive if people don't just come back with "yeah, you're totally right." I asked for your line of logic. That's it. All it requires is providing it. Example: "I'm basing it off of my [insert misinterpreted Kalitta story here.]" Note the lack of snark in the story.

 

I didn't mention it because the intent of my post was not to wave my story around to try and prove PMDG wrong.  I was merely starting a thread to see if other people were experiencing the same and maybe try to validate my "anecdotal" story.  I apologize for not communicating that clearly enough.  

 

12 hours ago, cimgrp501 said:

Tom...a thread started in Feb that has some credible info and sources chime in...eventually...may have some useful info in the event you wish to explore further the landing characteristics of the 74.

 

Thanks Roy!  I'll read through it.

Share this post


Link to post
Share on other sites

As a total layman, looking at videos of actual 747 landings it appears that PMDG have nailed it in the way that the nose wheel does not want to slam on to the tarmac once the spoilers have deployed. In fact it appears that the aircraft wants to stay in that attitude or actually want to pitch up slightly which seems to be in agreement with the easing forward of the control column.

 

Share this post


Link to post
Share on other sites

Very offtopic, but I salute your selection of videos. Icelander, and Iron Maiden fan in me is feeling good... #UpTheIrons

  • Upvote 1

Share this post


Link to post
Share on other sites
8 minutes ago, HighBypass said:

In fact it appears that the aircraft wants to stay in that attitude or actually want to pitch up slightly which seems to be in agreement with the easing forward of the control column.

Spoiler deployment causes a slight nose-up pitching moment (the outboard spoilers more so than the inboards, hence why the QRH for a hydraulic sys 4 failure instructs you not to arm the spoilers for landing and instead extend them manually and slowly), which shows quite nicely in your videos.

Share this post


Link to post
Share on other sites

Taken from Steve Hall's post in the above thread. - "After touchdown don't just release the yoke but initially hold the attitude, select reverse thrust and then lower the nose and fly the nose wheel onto the runway."

So im not sure - getting a lot of conflicting reports on the subject.  All I know is (for me) once the mains come down, there is literally zero control input required; the nose comes down at a gradual rate on its own with the controls at neutral position.  

Share this post


Link to post
Share on other sites

Back to your first post Tom -  you don't have to add back pressure to the yoke.. you don't need to prevent the nose wheel from slamming down because it doesn't.

EDIT - holding the attitude isn't necessarily the same as increasing back pressure on the yoke; if the plane's attitude isn't wanting to change, then the yoke doesn't require any additional input.

Edited by HighBypass

Share this post


Link to post
Share on other sites

Tom, further to my original email it seems you might need a more definitive description of the 744's landing technique and longitudinal axis behaviour, so here it is:-

The landing flare of a 744 is initiated when the main gear is about 30ft above the runway (use the RA callout as a guide) by raising the nose approx 2 degs and then without delay smoothly reducing the thrust to idle. There is a natural tendency for the nose to want to drop as the thrust reduces, so during this time you need to be looking at the far end of the runway in order to control  the pitch attitude and judge your reduced rate of descent.  You don't want to float or allow the nose to drop, so hold sufficient back pressure to keep the pitch attitude constant and if you have judged it correctly then the aircraft will touch down on the main gears.approx 500m (1500ft) from the threshold.

After mainwheel touchdown the spoilers will automatically deploy - provided you have remembered to arm them on the approach!  If not then extend them manually and without delay select reverse thrust (on the actual aircraft there is an interlock which prevents full reverse power being applied until after the reversers have translated.to their correct position). At this point you need to fly (i.e.ease) the nosewheel onto the runway.  Again this is done smoothly and without delay and it must not be held off the runway or allowed to drop rapidly.  Spoiler deployment and Reverse Thrust tend to give a slight pitch up, but this is easily countered by brake application and control column adjustment.  There is a lot of inertia in this aircraft so it can be relatively slow to react to thrust and pitch changes, but provided you stick to the numbers and proven handling techniques it is a delight to fly.

Most normal landings in the 744 are performed using Flaps25 and autobrake with the A/B setting based primarily on the calculated Landing Distance and Approach Speed.  Landing with Flaps30 puts additional stress on the Flap mechanism, so it is used primarily in reduced visibility, when the runway is short, contaminated or hot and high and when any abnormal QRH procedure requires it.  Obviously there is a lot more to landing a B744 than this and I could tell you about its crosswind handling technique, abnormal landings such as the Hydraulic failure etc but I think this is outside the scope of this particular thread.  Probably the best way for you to learn what a normal landing ina B744 looks like is to sit in the QOTS Virtual Cockpit and carry out an autoland on an autoland runway using Flaps25, auto Spoiler and Autobrake 3. All you have to do then is sit back, watch closely and remember to select reverse thrust!

Happy landings!

Bertie.   

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this