Autopilot at 30,000 ft and higher?
 

Having a bit of an argument with someone that seems to think the following:

"Ask any airline pilot why it's necessary to have automation at 30,000 feet. They'll tell you that humans lack the dexterity to fly at that altitude, due to thin air."

Took a bit of back and forthing and now he relented a bit with this:

"So let me qualify my remarks about needing automation at altitude:
Today, yes, planes with fly-by-wire can fly manual at 30,000 feet."

He's still adamant that manual flight above 30,000 feet without fly-by-wire can only be done with automation.

I've challenged him to post on a forum like this but he's reluctant to do so. Seems pretty silly I know but it be great to hear from people who do this for a living. No sense bringing up anything about military flying since he'll just brush it off with how they say and do what they are told.

Its necessary to have automation at 30,000ft because RVSM airspace starts at FL290 and goes up to FL410, and the FARs require use of an autopilot for cruise in RVSM airspace.

Most airliners fly at or between these altitudes which requires use of an AP, and many airline FOM/GOMs require or "strongly suggest" use of autoflight systems during most phases of flight.

I hand flew at FL450 while part 91 once; of course that was a bizjet and not an airliner but somehow I'm still here to talk about it on the internet.

Just in case the OP is not familiar with RVSM airspace, that means "reduced vertical separation minimums". Essentially 1000' vertical separation between aircraft. The mandatory use of autopilot in RVSM airspace is a safety risk mitigation requirement to help prevent altitude deviations.

Well, I guess I'll have to strike all of that T-38 cross-country time at FL390 (hand flying at .9M) from my logbook, since apparently it isn't possible.

I do love the duality of you friend's argument though; on one hand, "humans lack the dexterity to fly at that altitude, due to thin air", and on the other, military guys can/do it because "they say and do what they are told".

I used to hand fly in the mid to upper 30's all the time in the military. Yeah, there is that RVSM issue nowadays.

No reason one can't hand fly in 'thinner air'. One can still do it now to check the trim/retrim or whatever if needed.

To clarify, the FARs require an operational autopilot. There is no requirement in the FARs that it be engaged. Approved manuals for part 121 or 135 operators may have more strict requirements than the FARs.

There's a legal difference between "operational" and "operable".

I've hand flown a 727 at 42,000 feet. Definitely not a fly by wire aircraft. Autopilots are normally used in cruise because hand flying becomes tedious after a while. Nothing to do with "dexterity" or "thin air."

Actually the FARS, specifically Appendix G to Part 91 only says "the aircraft must be equipped with at least one automatic altitude control system ..."

AC 91-85 says "An automatic altitude-control system should be operative and engaged during level cruise, except when circumstances such as the need to retrim the aircraft or turbulence reguire disengagement." Of course an AC is only guidance.

Autopilot kicked off on the CRJ once at 34,000; airplane instantly became inverted and uncontrollable until the captain managed to select the a/p back on. Scariest 16 seconds of my life.