Autopilot & other procedures in heavies

[Eight Ball]

G'day,

Was just chatting to a few aircrews from a couple of overseas airlines the other day and they have different answers to these questions. I was wondering if I can get your input on these.

1. ) At take-off, what altitude do you engage the auto-pilot ?
2.) During the localizer intercept, do you do this manually or does the airline require you to intercept it using the autopilot ?
3.) At the glide slope, what altitude do you disengage the auto-pilot and fly it down manually ? assuming Cat3c is not an option.
4.) Do you use reverse thrust and spoilers all the time ?

Thanks in advance.

Eight Ball
( on the corner pocket )

[gas-chamber]

Every airline and every type is likely to be different. ATR encouraged the autopilot on the ATR 42 to go in at 400 feet after takeoff and stay there until 200 feet on the ILS or lower if weather was right on cat 1 visibility.
Other early types have a minimum of 1000 feet after takeoff for engagement, down to typically 1000 feet on non-precision approach and most of even the old types will allow engagement to remain down to at least 200 feet on a coupled ILS approach.
Later types of course allow a full auto-land.

If the autopilot does not like an automatic localiser intercept, i.e. it overshoots and takes a long time to settle down, some pilots prefer to steer it on in heading mode before engaging VOR/LOC.

Follow the AFM or company SOP. In the absence of either, do what works best for the particular installation and your own and passenger comfort.

One thing is for sure - at the 1st sign of an abnormal or emergency, a good autopilot is your best friend and should be used if available.

Personally, I keep the hand flying practice for fair weather and preferably in a radar environment, and use the autopilot as much as possible at other times.

[gas-chamber]

Oh yes, and I forgot. If spoilers and reversers are fitted, they are there to be used.

[Tagneah]

Can only speak for my operation and A/C type:

1. The Autopilot must not be engaged below 400ft. This is an AFM limitation. Any varience to this is a company limitation.

2.Once you get to know the A/C then you know how the Autopilot handles certain conditions. There are a few considerations such as your speed in comparison to the VNAV speed the aicraft "wants" to be at. Head or tailwind on the turn and the size of the turn. For example the turn onto the 23 localiser at Adelaide can be tricky at night with an easterly (or even Katabatic wind) if you are joining from the DRINA arival. The turn from the BLACK arrival is not as great so a little easier. A rule that I use is for a 90 deg tun onto the LOC, start the turn at 1% of your ground speed. EG turning at 210kts, start the turn in at around 2.1nm to the LOC. Then just fine tune the turn with the bank angle selector so that the Position Trend Vectors (little white lines on top of the Aircraft symbol) line up with the LOC course.

3. The limitation (AFM)is that the autopilot shall not remain engaged below 50ft AGL. Once again companies will have different rules but thats the one the manufacturer sets out.

4. We use Spoilers all the time (unless they're broken!) There are performance penaltys if they or some part of the system are U/S. As for Reverse Thrust. We dont have to use Reverse thrust as the normal landing distance of the aircraft is predicated without the use of it. So If we were rolling through to the end of a very long runway we might just "Crack" the reversers so that the reversing sleves open, but the engine stays at idle.

Gas Chamber summed it up well. At the first sign of an abnormal situation the auto pilot is your best friend. It helps "unload" you to concentrate on the problem. It should always be monitored though. It is just a computer and so suffers the old "Bullsh*t in Bullsh*t out" syndrome. My company allows us to handfly whenever we want but handflying an ILS down to the minimums in driving rain on the back end of a red eye is not the best time. If the conditions (both meteorological and physiological) and good then I try to hand fly as much as I can. Especially is there is a session in the lurching cave coming up!

[Lord Snot]

at the 1st sign of an abnormal or emergency, a good autopilot is your best friend and should be used if available.Unless it's an auto-pilot malfunction...

The above quote is what the pundits say - make maximum use of the automation. BUT there are plenty of times when you see the machine being jerked around by ham-fisted use of the Mode Control Panel. Often this happens in the simulator when the pressure is on.

There are times when the auto-pilot, often through no fault of it's own, is your enemy and the best thing to do is disengage it, get the aircraft delivering the performance you want, with the correct modes engaged, and then re-engage the auto-pilot.

Of course this becomes harder to do in these days of greater dependence upon the automation in the first place. Where I work they expect engagement at or above 200ft and disengagement near the minima and as such, hand-flying skills of most of the guys are poor.