To Follow or Not To Follow The F/D

[Sky_Captain]

Me, I've only started on the 737, and its my first "Big Jet", but I found myself a little lost last week while in the sim of a 737NG. Most of my training has been done on the Cranebank 737-400, and this was my second time in the NG sim.
My problem came about while on a single engine ILS approach. I was given an auto-pilot failure after VOR/LOC and hand flew it from there. When I armed APP and the flight director followed the ILS fine until about 3 or4 miles.
To my lack of knowladge, I was a little unsure of NG power settings for single engine approach (anybody with those figures for a LW of 55tons please let me know) but I did my best to maintain the VREF ICE speed. What happened next totally lost me. I drifted slightly right of the LOC and when the F/D started moving left I followed but never got the dot right in the centre, after that it continued left and even when I was at dead centre with my dot it continued left while the LOC moved right
In the end, this problem cost me big, a partial pass on my OPC

I eventually gave up on the flight director and followed the LOC, and yes the right frequency was in and idented and the right course was set on the MCP

So what do the experts think? Sim Fault, Bad Flying or just the way the 737NG F/D acts.

Thanks for any replies,

S.C.

[Rainboe]

Sounds to me in the struggle to hold on to the single engine approach, you might have let your trim go out of line. The flight director only gives correct indications if the aeroplane is trimmed out properly. Watch the position of the control wheel and try and keep it horizontal.
*PS don't worry, we all do it. I did the same on an engine out NDB approach and scored about 2/10 on my own estimation!

[Sky_Captain]

Good Point, I suppose with the constant changing of power and pitch settings I had no way of keeping it trimmed. Worst was that a 20kt cross wind didn't help
So that leaves me with a problem, have no idea when I will be re-booked for another OPC, cant afford to travel abroad to practice in a good sim since we dont have one in the green isle, I guess I'll just need to learn pitch power settings for the NG.

Anybody start me off with a rough guide for both single and 2 engine approach?

Many thanks,

S.C.

[Rainboe]

Flying this self same sim, I found it no help trying to memorise power settings. Just remember that you need a fair chunk more power on S/E and fly the aeroplane!.

[Sky_Captain]

I know what you mean, but my conversion course wasn't the best. When I flew the 400 at BAFT I got pitch/power settings for everything, then got nothing for the NG. Havn't been in a sim or flown in 3 months and was expected to fly perfectly for my OPC
I suppose since I have to re-do this part again I just want some figures in my head to try so I don't fail
How I hate playing the waiting game

S.C.

[Updraft]

The Flight Director gave me a lot of grief in my initial Ng time. Sometimes you need to "look thru" the F/D.
Try the following figures as a starting point and fine tune from there.
Prior to G/S slope capture single engine, think 5,6,7,8.
5 degrees flap
6 degrees attitude
78% N1
1/2 dot under slope, gear down, flap 15, maintain 6 degrees (a little forward pressure required)
At G/s capture 2.5/3 degrees attitude and approx 73% N1.

Two engine figures can be extracted from Flight With Unreliable Airspeed tables in QRH.
ie 737/800 24k 60 000 kg
Flap 30 1 degree attitude 58% N1
Flap 40 -.5 degree attitude 64% N1

Use these as a start point and fine tune from there.

Good Luck!

[BOAC]

To add, for the -700 from Boeing QRH:

2-eng
60T F15+10, pitch 3.5, 51% N1
50T """""""""""""""""""""46%

Always been taught to add about ?10%? for OEI (oh to ever settle down at an N1 ), and, of course, do NOT try to be smart and fly (Vref15+10)+5. Get a little slow and whoops!

.....and.....always look 'through' the F/D when flying the ILS, 2 or 1 engine. I preferred the inverted 'V' F/D myself, as I always felt it was more positive.

Check PMs

[Sky_Captain]

Thanks for the replies everybody, bit nervous about failing my first OPC and every bit of advice helps.
Updraft, some nice ballpark figures there for me, I'll definately try them and fine tune as necessary, Thank You

BOAC, also many thanks for the help. Send you a PM now.

Any other good tips for man-handling the NG out there, then please post them here.

S.C.

[Rainboe]

I think we all, or almost all, fail checks from time to time- I certainly have and I am not ashamed to admit it- and more than once! I haven't killed anyone yet, and neither have you. You sound as though you are doing it all with minimum experience or great lack of ongoing experience. You just have to put it behind you and thrash away and do your best. You are not going to stumble and drop out having come this far- you've already done 98% of it- just persevere and don't get disheartened. This is what you've set your heart on- just do what needs doing and you will get it.

[Sky_Captain]

Thanks Rainboe, I've given up everything for this and right now i've too many bank managers knocking on my door for me to fumble at the last hurdle. All I need now is a date to redo what I missed in the OPC and a start date for going on line. Wish it was easy to get those!

Its encouragment like that I need, Thank You

S.C.

[Truckmasters]

Simple question - depending on how long you have been playing with F/D?
Did your annuciators indicate that the app mode had captured. I have seen guys have the HDG bug on RWY HDG and the F/D has never come out of HDG mode due various issue. Just something to watch

[Sky_Captain]

Yes Truckmaster, APP mode had been selected and was shown in the annunciator. HDG and frequencies were also correct. The examiner on the day believes it was due to the aircrafts drift and momentum, I think he meant it was crabbing to the right of the LOC and even though I turned the nose left it continued to crab. The cross wind was 15kt coming from my right?

So Can the NG easily crab

S.C.

[Rainboe]

You were out of trim. Nothing else! Forget crabbing- that's irrelevant. The Flight Director indications are only correct if you are correctly trimmed.

[Sky_Captain]

My appologies Rainboe, i'm not discrediting your answer, it was just what the examiner said that threw me. Although you are right about the trim, at flap 5 I was trimmed then after gear down flaps 15 I did not touch the trim. Next time i'm in the sim, i'll correct for trim and hopefully things will go my way

S.C.

[FlapsOne]

It sounds almost certain that you were out of balance.

The 737 slip indications are punk so the only good way of doing it is to 'kick' (rudder) the control wheel till it sits horizontally.

Correct balance is the absolute key to flying OEI half-way accurately.

You have a tremendous amount in our favour that you have recognised a problem and are taking steps to recover. keep that attitude and you will get there.

I have to say though, I would have been a little disappointed with the attitude of your instructor/examiner if I had left a part failed OPC/LPC without receiving a full and clear explanation of the reasons and causes of the fail.

Did you get another go at that part of the test?

[Rainboe]

Sky-Captain, the way you mentioned trimming was as if you had it trimmed out at Flap 5, selected landing config and trimmed, and left it at that. Every power change, no matter how small on one engine, every speed change, you have to retrim it out. Don't bother with the rudder trim too much, you can't keep taking your head away from the panel. In your scan, keep checking the control wheel. Your feet should be fairly frozen on the pedals- as you increase thrust, push a bit more rudder on, as you decrease, take a bit off, but all the time in your scan, you should check the wheel horizontal. If it starts tipping, move your foot on the lower side of the control wheel. When you start going out of trim like that, the Flight Director is no longer giving you USDA Grade 'A' information!

Forget worrying about crab- that is nothing to do with it. If you are in trim, the FD will sort that out for you.
Remember, trim, trim, trim, then for good measure, trim again. You should walk out of the sim with a trembling leg!

Don't worry- you will walk it next time.

[Sky_Captain]

Rainboe, I promise you know, i'll limp out of that sim if it means passing. I was a little unsure if it is necessary to continually trim the rudder when coming in for landing or just taking it all in your legs and "leg flying it"
Also I'll keep a good moving eye on my elevator trim

FlapsOne, Thanks for the advice, I never fear asking for help, and always find a lot of good people on this site willing to share their expertise. I can't blame the examiner too much, I was lost as to what had happened and took his explanation to heart. Although, at my low hours experience and this being my first type rating, I felt it a bit tough to be expected to perform perfectly after being made to wait 3 months since my LPC and last bit of flying, for an OPC. I wish I could have afforded some practice time in a sim between those 3 months, but having to travel to the UK and then pay for an NG sim, well right now its beyond my budget. Just sold my car to pay to redo the part of the OPC I failed.

But anyway, enough of my boring story I'm just waiting now to find out when that OPC renewal will be.

Thanks again,

S.C.

[Rainboe]

Get this clear SC. At some stage set up a reasonable rudder trim (about 4 I think it was). Leave the trim alone after that- now your legs take over completely. Lock your heels on the floor, and hold it. Make small movements in line with thrust on final approach, but you will be holding quite a lot of rudder pressure. As you push thrust on, press rudder, and vice versa, frequently checking control wheel for horizontal. When you go around, trim elevator forward, and slowly press on rudder as thrust increases- don't slam the pedal forward- it is a balanced process and it comes on quite slow. Rotate the aeroplane. Think about LNav and AA, then what you want to retract flap to and level off altitude. Watch out for that rudder trim again- big power changes- keep watching that damn wheel.

I managed to kid people I could fly a 737 for many years with that- it works!

[Sky_Captain]

Thanks Rainboe, I greatly appreciate your help

S.C.

[Rainboe]

That's half of it. Next 50% is your morale! You ARE going to go in there and you ARE going to show that despite not nearly having enough practice, you ARE going to produce a creditable performance which may not be the best they've ever seen, but considering your basic lack of practice, it is still going to be damned impressive, and it will be a privilege to sign your licence so you can get out there and get paid to have more practice and really show them what you can do when you are allowed to get some proper training in!

Did you follow all that? Are you going to whap their ass next time?