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Member
Registered: Aug 2014
Posts: 95
Hello Peter,

in the FCTM, Boeing recommends to set the minimums to MDA+50ft for a NPA, because in case of a go around the aircraft won't descend below the MDA (due to inertia). In your video, you set the baro minimum to the MDA value. Why ? Is it specific to airline SOP ?

Stephane
« Last edit by calimhiro on Sun, 03 May 2015 08:23:58 +0000. »
Member
Registered: Aug 2014
Posts: 375
Location: Camberley, UK
« Last edit by Britjet on Sun, 03 May 2015 08:47:53 +0000. »
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Registered: Dec 2009
Posts: 334
Location: KTPA
Member
Registered: Aug 2014
Posts: 95
thanks for the reply, Peter. What is confusing me now is :
Quote
DA(H) applies to Category I, II, and certain fail passive Category III operations

Cat I, II or III means an ILS approach for me. Then you talk about VNAV DA, and if I understand, we use VNAV when performing a NPA.

Stephane
Member
Registered: Aug 2014
Posts: 375
Location: Camberley, UK
Hi Stephane

Unfortunately the FCTM is a bit confusing...and it is easy to use "DA" when you mean "MDA", as I probably have done!

The 3 category ILS approaches you mention are of course "precision" approaches using an ILS (I've seen a lot that weren't <g>).

Unless otherwise specified, (ie for Cat II and Cat III, which use radio) they use barometric altitudes referenced to the threshold elevation. Cat 1 DA(H)'s are not radio altitudes, as I am sure you realise, the (H) merely means that the reference is the runway threshold.
(CAT I approaches always use baro reference since the radio altitude is unreliable as an indication of height above threshold. The radio height given after DA(H) in brackets on a CAT 1 is advisory only, by the way - there might be uneven ground so you don't use it- not the case as for the late stage of a CAT II or CAT III approach)

"Non-Precision" approaches in the 747 are always continuous descent approaches. You can't fly level and then start a last-minute descent, so they are flown 99% of the time with VNAV guidance. So, you arrive at your barometric decision altitude, DA(H), still descending, just like an ILS. Then if you go-around, the DA(H) that you were using is still safe as there is a safety margin built in.

If you get an approach with no VNAV guidance, then the approach should specify an MDA(H) instead of a DA(H). In this case you cannot reasonably fly level, but you mustn't go below it if so specified - so you add 50' in this instance..and you still fly it as a CDA..

So basically (!) a DA(H) for an ILS is the same as a DA(H) for an NPA..you fly it as a CDA using baro, and go around when you reach it..(or land!)

Peter
« Last edit by Britjet on Sun, 03 May 2015 18:45:54 +0000. »
Member
Registered: May 2011
Posts: 143
Indeed, NPA's with DA's should be flown as an ILS...

An MDA is a floor. Bust it and you fail your checkride. It comes from the principle that you cannot be below that altitude at any time if you are not visual with the runway. The principle is related to "old style" NPA's, without much of a vertical guidance (who remembers NPA's where timing was your only clue...). In a commercial environment, if you really wanted to land, this pushed the crew to descend quicker than required, leveling off at the MDA and start looking for the bloody runway. But it was better than descending too slow and becoming visual over the threshold.... The risk of busting your MDA during such maneuvering is pretty high, so standard 50ft were added to the minimums.

Pretty much all NPA nowadays are continuous descent and if managed properly, you get a very good path control that leads you straight to your VDP (visual descent point). Beyond that, it's your aircraft that allows you to do the same thing for those old style NPA with the letdown principle. It then depends on your authorities if they allow you to use VNAV for those types of approaches (approaches with an MDA published, not yet a DA). If not, the 50 is usually still added (like in my company).
« Last edit by IefCooreman on Sun, 03 May 2015 19:29:31 +0000. »
Member
Registered: Jun 2014
Posts: 317
Hi pete, just a question about the tearpdrop on your NIDA vid. On the chart it says that heading 346 should only be used by cat A and B, does that not include the 747?
Member
Registered: Aug 2014
Posts: 375
Location: Camberley, UK
Er - I think you might have misread it...
Cat A and B- 342
Cat C and D -346.
It's to do with the radius of turn of course..

(747 is CAT D..)

Cheers

Peter
« Last edit by Britjet on Mon, 04 May 2015 15:30:13 +0000. »
Member
Registered: May 2009
Posts: 202
Location: The Netherlands
Hardy and Peter,

Just a small dilemma here...

I really think we -all- are enjoying the magnificent video's of both of you VERY much.
The learning effect is magnificent and a very good addendum to the manual.

Nevertheless it's not very convenient to say "thank you" after every upload.

So, if it's quiet for some time with "thank you's...", be assured that the not written "thanks a lot" is always included in the previous one's".

Hessel

p.s.

May be helpfull for newcomers, if the links to Hardy's video's are also put in the "Tutiorials-section" of the forum ?
Member
Registered: Aug 2014
Posts: 375
Location: Camberley, UK
Hi Hessel,

Sentiments appreciated. Thank you!

Peter
Member
Registered: Nov 2010
Posts: 139
Location: Vienna
Fully agree with Hessel!!!

THANKS A LOT!

BR from Vienna
Hans
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Hans G. Schuetz
http://B747-400.net
Member
Registered: Aug 2014
Posts: 375
Location: Camberley, UK
New video uploaded..
"Single Engine Failure - handling".

This video is just about handling the failure itself - the next video will deal with managing the failure - gear and flap clean up - "emergency turns', checklist use etc.

Cheers,

Peter
Member
Registered: Aug 2014
Posts: 80
Per Hessel, my continued thanks too!
_______________
Greetings from the rice fields of Thailand (VTUJ),
Chris Stanley.
Member
Registered: Aug 2014
Posts: 95
Another great video, thanks.
In the future, I would like to see how you handle with turbulence, when landing at Sydney for example.

Stephane
Member
Registered: Jul 2009
Posts: 148
Location: Loomis California (near Sacramento)
A comment on the use of the rudder on an engine failure/ The video shows the yoke offset a bit from the center position with the rudder not sufficiently dealing with the yaw/roll problem.

My old company had a VERY close call because of that !

The aileron deflection in that (mishandled) event was enough to bring up the spoiler, and as a result the airplane almost hit the hills west of ksfo !
Moderator
Registered: May 2009
Posts: 5140
JJ, the spoilers don't go up when the aileron is deflected just a little bit (like in the video). You can see that on the EICAS.
Member
Registered: Jul 2009
Posts: 148
Location: Loomis California (near Sacramento)
True, but in the case that I mentioned he had in almost full aileron which was part of his problem. (The other part was that they didn't go "out the gap" as called for to avoid the terrain).
Moderator
Registered: May 2009
Posts: 5140
So your old company prohibited even such slight (spoiler-less) aileron deflections?
Member
Registered: Aug 2014
Posts: 375
Location: Camberley, UK
Actually - although the indicator on the video shows a lot of aileron applied - it was very small - only a very slight deflection with a joystick..

If I recall correctly there was almost no rudder input on that particular event hence they continued to track incorrectly for quite a long way - not "through the gap" as you say.

(If I remember, he didn't almost hit the hills because of spoiler drag - he was tracking incorrectly because he was out of balance, hence the problem - but I would have to look at the incident report again if there is one).

Rudder must come first - as emphasised in the video, but it is important not to play around with rudder close to the ground - there is no doubt that the 747 will bite you if you do that. Wings level initially is paramount, and you can only do that effectively with aileron - (the secondary roll from any rudder correction is too slow).

My "4 R's" are looking for a (R)eassessment at about 100ft or so - not a sustained out of balance, which is what happened in the SFO case..

PS - Just had a quick look at the Pilot report - it was a No3 engine failure failure at about 300ft, so not an engine failure between V1 and Vr as such. A failure like this is easy to miss, and difficult to handle correctly - because yaw may not be noticed but the roll will be - so the natural tendency is to apply aileron and nothing else.

"NFP NOTICED THE FLYING FO LOST 40 KIAS DURING THE INITIAL CLBOUT"

Unfortunately this seems to have been mishandled to the point that they got the stickshaker. I don't personally think that spoiler drag was the issue...

Peter
« Last edit by Britjet on Sat, 16 May 2015 15:28:55 +0000. »
Member
Registered: Jul 2009
Posts: 148
Location: Loomis California (near Sacramento)
I've not seen the report, but the reconstructions of the event that were around at the time indicated (as was pointed out) that there was almost no rudder input, and that the spoiler drag and the close to a stall airspeed all played a part. The airplane apparently came within about a wing span distance from a hill!

(And one of the KSFO tower operators happened to live there! That was apparently how the word got to the media).

In any case my point is that it's not a good idea to put a lot of aileron in, an an even better one to follow the departure path for the engine out.


Also there was no company policy regarding the spoilers as you mention Hardy. Just a very badly handled engine failure on take off.
Member
Registered: Aug 2014
Posts: 375
Location: Camberley, UK
I think we are all agreed on that - as I said in the previous (edited) post - although it looked a lot on the PSX indicator the aileron input in the video was actually a very small amount - the rudder having been applied pretty accurately..

It would be an interesting exercise to see how much deflection on your joystick/wheel causes spoiler pickup - on the real aircraft I seem to remember it was about 20degs wheel deflection..
« Last edit by Britjet on Sat, 16 May 2015 15:37:41 +0000. »
Member
Registered: Aug 2014
Posts: 375
Location: Camberley, UK
calimhiro wrote
Another great video, thanks.
In the future, I would like to see how you handle with turbulence, when landing at Sydney for example.

Stephane


Thanks Stephane..

I would only quote my own technique in turbulence which probably has no particular merit - but..
The real aircraft experience - because of the length of the fuselage you go vertical and sideways quite alarmingly! Not comfortable. It is a bit like not being totally in control of an office-block on a roller-coaster!
Airspeed trend vector can be alarming but really doesn't help much except to make things look bad - remember it is a 10-second vector and a gust rarely lasts more than a second or so so it is important not to be 'panicked' if you see the trend vector going into the stall area!

1) Fly attitude - try to hold the pitch you want even if the aircraft is pitching up and down in the gusts. Don't worry too much about glideslope - the important thing is the touchdown point. For a very high ROD (say 1200 fpm?) then strongly consider a GA.
2) Use a healthy speed increment (up to 20 kts)
3) Many pilots like Flap 30 in windy approaches. It helps prevent a float..Just watch the flap protection envelope..
4) Don't use autothrottle, apply a datum thrust and try not to change it too much.
5) If you see an unhealthy speed trend that persists then make a sensible thrust change - slamming throttles backwards and forwards may make you feel better bit won't help
6) Try to resist overcontrolling in aileron - it is easy to do!
7) Don't hold off - floating 10 feet above the runway in a gale with no visible means of support is not a good idea! Better to crunch it in!

If directional control goes wrong then strongly consider a go-around - even after touchdown if the reversers haven't been deployed.

As I say - just my ideas..

Peter
« Last edit by Britjet on Sat, 16 May 2015 17:08:15 +0000. »
Member
Registered: Dec 2011
Posts: 497
Location: Portugal
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Jose Monteiro
Member
Registered: Aug 2014
Posts: 375
Location: Camberley, UK
« Last edit by Britjet on Sat, 16 May 2015 17:07:20 +0000. »
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