This question regularly comes up when discussing aviation with non-aviation people and as I’m not in a position to answer this based on own experience…
How common is it to have a “configuration” of aircraft, crew, and airport fit for auto-land? I do realize it’s executed rarely because crews prefer – and should prefer – manual landings for many reasons, most notably currency.
I found that most large airports in Germany support CAT III operations so that solves the airport side of the question (at least for one sample country).
How does this relate to aircraft equipment and crews? Are airliners, say the typical A318 or A320, usually equipped with auto-land systems or is this still rare and rather fitted to larger airliners such as 747 and A380?
Would you consider an auto-land system more useful for an aircraft flying mostly short-haul flights (with lots of landings per day, but the opportunity to delay the flight when the weather at the destination in an hour is known to be bad) or for an aircraft flying mostly long-distance (with less landings “per day”, i.e. less exposure to the “problem”, yet less chance to forecast the WX at the destination when taking-off, say, 12 hours before)?
Patrick wrote:
How common is it to have a “configuration” of aircraft, crew, and airport fit for auto-land?
For airliners? Very common. Patrick wrote:
How does this relate to aircraft equipment and crews? Are airliners, say the typical A318 or A320, usually equipped with auto-land systems or is this still rare and rather fitted to larger airliners such as 747 and A380?
All of them. Very few operators can’t do CAT III. It happens occasionally that there are downgrades resulting in diversions or aircraft changes but not regularly. In Europe, airline flying without it is pretty pointless.
All common short haul types are CAT III “out of the box”, as are pretty much all long haul types.
Some turboprops (Dash 8 I believe) are CAT II hand flown. Many bizjets are CAT I only.
In winter on the 737, I have weeks where one might do 5 CAT III approaches for real (I did one last night due cloudbase) and others where you don’t do one in a month or two. Many smaller airports don’t bother paying for/are unable to meet CAT III certification criteria so are stuck at CAT I.
I would consider the systems of equal use to long haul and short haul (though bear in mind I have yet to fly long haul) as for short haul without it you will divert a lot, and for long haul it makes your planning minima for any CAT III enroute alternate CAT I RVR which makes finding alternate much easier.
We only autoland when weather dictates as we all like flying, not button pushing. The autoland on the 737 is frequently embarrassingly firm if you have proudly announced to your passengers that you are flying that sector!
out of the last 800 hours (approx 1 year) of flying for a short haul airline in Europe, I have done 10 auto lands (CAT II or III). I would say about half of these were because of weather and the other half for other reasons such as crew currency or technical reasons (sometimes an aircraft has been downgraded to CAT I only and needs to have an auto land performed in CAT I or better weather and recorded as satisfactory for CAT III to be reinstated). Basically however it is very common that the aircraft and crew will be qualified and weather the runway is or not just depends on where you are going that day.
What Josh says is right though, I would say nearly everyone prefers to fly themselves, and even those that don’t would probably prefer to do it manually just to avoid extra briefing (as per my company anyway) for the auto land.
I will agree that it is also more than a bit firm at times as well, especially if there is a non uniform terrain profile in the last mile or two. Knock (EIKN) springs to mind and I am sure Josh would agree if he has experienced an auto land there.
Josh wrote:
long haul it makes your planning minima for any CAT III
Patrick wrote:
How common is it to have a “configuration” of aircraft, crew, and airport fit for auto-land?
Most airliners and their crews are fit for autoland. Most larger airports are so too. The latter would have to impose larger separation and protect critical ground areas from interference, thereby considerably reducing the number of possible take offs and landings, which will lead to delays.
Flying shorthaul and having a foggy homebase will give you many CATIII’s during the winter. Longhaul you might not see one in real life for a few years, but will keep current in the simulator.
To the point on the impact on airport movements, EDDB was reporting Cat II on the ATIS on Monday when vis had risen to comfortable CAT I. A Ryanair was asking for the Cat II ILS to 07L as I was inbound. ATC was clear that if they wanted it they would have to wait quite some time due to the volume of traffic. I assume either they were wanting to do one for crew or aircraft reason or procedures require it whever it is on the ATIS.
JasonC wrote:
I assume either they were wanting to do one for crew or aircraft reason or procedures require it whever it is on the ATIS.
Not familiar with their procedures but I assume it is just a way to play it safe: It the conditions have just improved from CAT II to CAT I and they accept a CAT I approach for the sake of other traffic, it will be their “personal fault” if they have to go-around because RVR drops below 550m again while they are on final. The airline in question does not easily accept “personal faults” of their crews (I am told…) so I can understand why they stick with CAT II.
But I have a question for the airliner pilots regarding those heavy landings out of CAT III approaches. I experienced one myself as passenger earlier this year into Vienna – I thought it would bounce back into the air – never did such a hard landing myself in anything I ever flew…: Is it not allowed to take over manually once visual contact is established on a CAT III approach, just like on any other approach? I can understand that in real “zero/zero” conditions the autoland must do the job. But in a case like that Vienna landing where, looking out of the side window, something like 200-300m visibility and 100ft ceiling would have permitted some degree of flaring, why stress the airplane like that?
Airports cancelling LVPs the moment the weather is CAT I is a great bugbear – why stress yourself in marginal conditions when you can autoland? Having time doing both, CAT II/III capability is a great stress reducer. I have had horrible days on the Lear where everywhere in sensible alternate range is marginal CAT I at best and it is no fun whatsoever.
Regarding firm landings, I t’s safe and certified. The 737 will certainly withstand plenty of abuse. It’s merely uncomfortable rather than genuinely hazardous – one sometimes gets the feeling that the aircraft “gives up” at about 3-5 feet and just drops. I should also confess to on occasion drilling it in harder than the autoland!
Both autopilots must be engaged to touchdown or a go around performed – that’s in the aircraft limitations. One reason on the 737 is that the aircraft trims strongly nose up at 400ft agl to help with the flare and missed approach, so any autopilot disconnection below that height and the aircraft will be significantly out of trim.
I personally wouldn’t fancy a last minute manual intervention to land at 100ft/300m! I find landing manually off a CAT I in limiting RVR hard enough in a manoeuvrable bizjet, I don’t think I’d fancy it at half the height and vis in the 737.
Weather was 4000m vis so well out of LVP. Not sure why it still said it on ATIS.
I normally end up doing about four or five full blown CAT3 landings a year.
I have had two failures below 150 ft AGL one resulted in a GA as I could see nothing at all, the other was the aircraft started heading for the runway edge at about 30ft AGL and I disconnected the AP and manually landed the aircraft.
I’m not at all sure that CAT3 capable aircraft lower my stress level or not ?
