View Full Version : Boeing 767-300ER Autoland Catagories.
Otterman
22nd Jul 2003, 18:52
Just transfered to this aircraft. Nice airplane. I fly for a major in Europe. Our home base is frequently schrouded in fog. We fly the aircraft to CAT III b no DH RVR's 75m limit.
My question is in regard to a downgrade. When Land 2, no Land 3 comes into view on our ASA we downgrade to CAT III a (Fail Passive) with a DH of 50, touchdown RVR needs to be 300m mid 125m rollout 75m. I was talking to an instructor for an American carrier who told me that with this annunciation they downgrade to CAT II. Still waiting for an answer from our flight technical department. This would make sense to me in that my previous airplane (Boeing 747-300) would become CAT II when we were down to two autopilots. Is there anyone who can shed some light on what your flight department does.
Waste Gate
22nd Jul 2003, 19:08
Otterman,
I fly 767-200ER & 300ER.
Like the American instructor, we revert to CAT II for a "land 2 / no land 3" ASA annunciation.
Cheers.
WG.
Otterman
22nd Jul 2003, 19:20
We fly our Boeing 737 series (we have almost every versions except the really old ones) down to CAT III a Fail passive DH 50 RVR 200/125/125 (it has two autopilots).
Our Boeing 747-400 same autoflight system as the Boeing 767-300ER also has the downgrade Land 2/No land 3 down to CAT III a Fail passive DH 50 RVR's 300/125/75.
I remember the DC-10-30 that we had were CAT III b auto-rollout with two autopilots but they were dual channel, don't believe ours are. It is not becoming clearer to me, yet. Would love to hear what Boeing says.
Joe Monsoon
22nd Jul 2003, 20:58
Otterman In ours land 2 no land 3 we go back to 3a ( 200-75-75) in some airports thay want min of 125m mid rollout . Hope it helps. Have look at WWW smartcockpit.com ITS GOOD site and your right it nice bird to fly. :ok:
NigelOnDraft
23rd Jul 2003, 04:19
Nigel's 767s...
Downgrade to ASA2 is to CAT3A - 50R/200m, 150m Mid (No CL Lts), 75m (Cl Lts)...
Presume differnece is just airline / authority requirments. Never could get my head around why ASA2 meant CAT3A?!*!
NoD
B767300ER
23rd Jul 2003, 12:35
Otterman, in the US, at my airline, we do it just as you described. "Fail-Operational" for Cat IIIb and "LAND 3" annunciated, but "Fail-Passive" and Cat IIIa for "LAND 2/NO LAND 3".
I recently did a CAT IIIb into SEA where they were reporting 200 ft and 1/2 mile. We were suspicious of it, and set up for CAT IIIb Autoland. We did'nt see anything at 200, 150, 100 or even 50; at about 30, I saw the runway, and shortly after, a smooth rumbling announced our arrival onto the runway. As other aircraft were missing their approaches at 200 ft.DHs, we informed the controller that it was definately NOT 200 and a half mile!
Use it if you've got it!:ok:
B767300ER,
Was the viz below the 30 foot ceiling so good that the RVRs did not indicate the weather was below CAT I?
As an engineer I also queried this with our tech services guys as I was of the opinion that Land 2 is Cat 3a.
The reply I got was that for a particular failure scenario, although the a/c was then fail passive a subsequent similar failure would result in possible a/c configuration problems after a disconnect. This, coupled with the fact that our ASA is set up to display only on multi channel eng, meant that there was not enough time to carry out the drill to establish if the landing could continue as Cat3 or had to be downgraded to Cat2.
Hence for our ops Land 2 = Cat 2
looking into the system there is only one area where there are not 3 channels and that is the stab. I am not familiar with crew drills for Cat3 landings but I suggest it is possible that companies with a different SOP/pre-landing drill have in their proceedures a (probably quite simple) check that is done to ensure correct stab failure backup.
However I am prepared to back down on this as I was not very happy with the quality of the response from the tech services chap, in fact my initial response was :mad: if I recall.:ok:
Our operations also require CAT II for Land 2.
Bally Heck
25th Jul 2003, 04:47
With LAND 3 "a single fault cannot prevent the autopilot system from making an automatic landing (fail operational)"
With LAND 2 "a single fault cannot cause a significant deviation from the flight path (fail passive)"
We revert to 3a for LAND 2. Any further failure (below 200ft RA) will give NO AUTOLAND annunciation which requires an go-around unless adequate visual reference has been obtained.
Don't think any configuration problems could occur with LAND 2. Only a bit of nose up trim which is applied to assist in the flare.