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-   -   Practicing manual flying in jet transport ops. (https://www.pprune.org/australia-new-zealand-pacific/535610-practicing-manual-flying-jet-transport-ops.html)

Centaurus 31st Mar 2014 04:07


There is no place for handling a big jet at 41000 ft manually. Humans just can't do it as well as an autopilot to handle the reduced longitudinal stability at high altitude.
I am sure you are right. On the other hand it makes you wonder how RAF and RAAF pilots coped with flying Canberra bombers regularly at 45,000 feet and even up to 50,000 ft in IMC with no autopilot, no first officer and no weather radar and a tendency for both engines to flame-out unexpectedly at these altitudes due to compressor stalls.

Considering some of these youngsters pilots had less than 1000 hours total time, it says a lot for their basic instrument flying skills and of course manual flying skills. Could it be that your point "there is no place for handling a big jet at 41,000 ft manually" is not that it is potentially dangerous as you imply, but simply because pilots of big jets spend 98% of their time on automatics leaving little else to do but monitor the progress page.

With many operators today actively discouraging any form of hand flying both in the real thing and in simulator training, is it any wonder that hand flying a big jet at high altitude is actually beyond the capabilities of the average airline captain and certainly beyond the capabilities of the average new hire MPL.:ok:

Wally Mk2 31st Mar 2014 05:01

'Centy' am sure that was the case re Canberra Bombers being hand flown at night IMC SP but would they be doing so with the tolerances of what would be expected of today's drivers in say the ML-SY corridor @ 39K?
Also perhaps the design of the old girl thick wing lots of lift not as pitch sensitive for Eg as against today's rather delicately balanced swept wing machine was quite a bit different. I know having hand flown a LR35 at 39K was bloody hard work keeping it within +/-500ft even for short periods of time, besides as we know any Airliner experiencing equip failure in the order of no auto-flt systems means yr going down regardless to lower Alts out of RVSM airspace & a better environment for hand flying.
Personally I see no joy or real need to sustain accurate hand flying skills of a transport Cat jet at Alt,they where not designed to be reg flown like that nor are the drivers of today.
Hand flying a circuit in reasonable wx conditions is the only place to be getting any 'stick time' outside of a Sim.

Wmk2

maggot 31st Mar 2014 06:01

Oh centaurus, we are not worthy!
:rolleyes:


I dont like the look of those teenagers

Angle of Attack 31st Mar 2014 07:39

With any airliner maintaining FL380 in level flight even blind freddy could see there could be only one possibility with thrust at idle and full speedbrake deployed, and it ain't an over speed.

The Bullwinkle 31st Mar 2014 07:50

I enjoy hand flying the 737 at appropriate times, and I also encourage my F.O.'s to hand fly when appropriate.

And funnily enough, Centaurus was the one who gave me my 737 endorsement.

Coincidence?

Lord Spandex Masher 31st Mar 2014 08:06

I regularly hand fly the 737 at high altitude on check flights. Even in manual reversion it's pretty easy to maintain +/- 50', +/- 1knot and zero heading change (which is what is required for the check) . So;

- There is a case for high altitude handling of big jets,
- It ain't dangerous,
- Even with degraded flying controls it's achievable with accuracy,

Capn Rex Havoc 31st Mar 2014 08:14

Lord Spandex- The 737 is not a big jet.

Lord Spandex Masher 31st Mar 2014 08:25

If you don't want it to be a big jet then that's fine but I'd recommend some Androgel for you.

Me, I'm not bothered now big it is.

LeadSled 31st Mar 2014 15:08

Capt. Rex Havoc,
There is no appreciable difference between the high level handling of a B737 and a B747 Classic or -400. If anything, the various B737 models are marginally less stable.
The high level handling of the B747 was a big improvement over the B707, the -400 a big improvement over the Classic. The B707-120, and the even shorter QF -138, with Yaw Damper off, really took concentration, but the B707-300/320 with the Yaw Damper off were not so keen to dutch roll. With Yaw damper on, just concentrate ever so slightly less.
The B757/767 at high levels are interesting, because of the relatively low wing loadings, you have to work at it.
I have, over the years, regularly practiced hand flying at high levels, up to FL410, and any pilot who is not competent to hand fly an aeroplane throughout its flight envelope is not, in my opinion, fit to be on the flight deck.
Hand flying at high level, just straight and level does wonders for your scan, makes sims a pushover.
Today, we have the luxury of multiple autopilots, but it was not always so, how do you think we got on if the A/P was U/S ----- hand-fly all the way. Three of us did it SIN-JKT-PER-SYD one night, slept well when I got home.
Tootle pip!!

Capn Rex Havoc 1st Apr 2014 04:12

Lord Spandex - I was not having a go at you flying a 737.

LeadSled- I will have to disagree with you. Physics would have to dictate that a 380 at FL410 will have more inertia in any moment arm direction, therefore will be harder to accurately hand fly especially after a disturbance.

I know nothing of Boeing checklists- But the Heavy/Super airbus checklists call for the Autopilot to remain connected when in severe turbulence.

In my company- anecdotally, when there have been pilot disconnects of the Autopilot at High cruising altitudes due to overspeed's (twice over the the himalayas), serious Altitude busts occurred.

The message that the training department says - is

"Leave the autopilot in at High Altitude"

porch monkey 1st Apr 2014 04:26

Rex, Leaddie is giving you the benefit of his experience having actually flown the aircraft he speaks about. Yes, by hand. Not second hand. Inertia is only one factor in controllability, there are a few other factors that can influence each type.


Having said that, I'm in firmly in The Bullwinkle's corner, too. Thanks for your time and tuition in my past as well, Centaurus.

Angle of Attack 1st Apr 2014 05:29

747-400 and 737 flown at high altitude, well there's hardly any difference, if anything the jumbo was easier probably due to better yaw damper elevator feel hydraulics etc.. But not by much, still an aeroplane.....

sleeper 1st Apr 2014 05:53

I regularly fly a B777 to cruising altitude. It gets a bit more pitch sensitive, but that is all. Somebody said it was difficult to keep it within plus or minus 500 feet!? If so, you shouldn't be in a cockpitseat. it is easy to stay within 50 feet.

Capn Rex Havoc 1st Apr 2014 10:06

Gentlemen, - I think there may be a bit of confusion here.

Firstly - I am not talking about smooth conditions Autopilot off and maintaining straight and level.

I am talking in the event of an upset be it from an Overspeed event or wake turbulence or some such disturbance.

There is a key difference in Airbus from Boeing Heavy jets. (Again not wanting to start a boeing/Airbus feud)

The key difference is this-

All Wide body modern airbus have a trim tank that uses fuel. Fuel is pumped to the rear of the aircraft during the climb to move the centre of gravity aft to make the trim drag in the cruise less. This results in a marked decrease in longitudinal static stability. So as I have stated should one experience an upset at high altitude, best you leave that Autopilot engaged. :ok:

LeadSled 6th Apr 2014 08:51

Folks,
There is no question that it is preferable to leave the A/P in during turbulence --- and the major reason is physiological, in sever turbulence your eyes are subject to "eyeball bounce", actually the liquid in you eyeballs becoming turbulent and decreasing your visual acuity ---- and moderate turbulence might turn into severe without warning.
But, and it is a big but, if the autopilot can't handle it (admittedly a rare thing with modern autopilots) you better be ready to, and your best has to be good enough.
Old single channel analogue were a horse of a different colour.
Being a devout coward, I put a lot of effort into avoiding severe turbulence over the years, but fly enough hours for enough years --- and you will find bad turbulence --- no matter how hard you try not to..
Worst TS/CB I have come across was one night coming down to Luanda from Isle de Sal, worst non-TS/CB a toss up between down range from the Rockies, and a bad day over the Atlantic, or a bad day on the edge of a jetstream over Japan in winter.
Tootle pip!!

PS: A hint for those still flying B747 Classics --- even in light turbulence, take out the altitude hold and just use the A/P on attitude, if you haven't found this out already, you will be surprised how much of the turbulence was the elevators pumping, chasing altitude.

LeadSled 8th Apr 2014 15:33

Folks,
It is worthwhile having a look at the "Flight with unreliable Airspeed" on the Tech forum.
Seems both Boeing and Airbus are quite keen on the idea of manual flying with the A/P--A/T and FD off.
Tootle pip!!

Gnadenburg 8th Apr 2014 17:24

I'm new to the debate and I'm sure my strong position for raw data efficiency has been voiced by others.

I'll just quickly add, that I fly with MPL's & Cadets who seem to have had their raw data training cut so far to the bone, that when I encourage them to hand-fly, the standard is so rough and woeful that I ensure the seat belt is fastened for passenger safety.

This is how quickly the industry has run with what's deemed as acceptable skills erosion for cost cutting and training short cuts. I'm shocked at how quickly the problem has further manifested itself over the last few years in my part of the world.

It now seems acceptable too, for training captains to struggle with raw data proficiencies. This seems to be a betrayal from within, with a percentage of training pilots behaving like FCOM bureaucrats instead of instilling strong fundamentals.

Blueskymine 8th Apr 2014 21:07

Trim drag? In a jet with THS? Interesting.....

Here is me thinking it's because with an aft c of g there is less force required on the tailplane, which in turn produces less drag and as a consequence less fuel :)

I must be wrong :)

Capn Rex Havoc 9th Apr 2014 00:24

LeadSled-

Seems both Boeing and Airbus are quite keen on the idea of manual flying with the A/P--A/T and FD off.
Unreliable Airspeed and Severe Turbulence are two completely different checklist actions.

The Autopilot,FD and Auto thrust, probably aren't going to work to well without an accurate speed input are they?

Blueskymine- You are correct, but it is the concept of the reduced drag and reduced stability that I was pointing out.


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