CAT3B fail passive
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No, still dual autopilot for the 737 fail operational. The rudder hardover was kinda solved a bit before the introduction of the fail operational system if i remember it correctly and was a different problem alltogether.
The fail operational 737 needed a rudder servo and rudder channel in the FCC which meant new FCCs, the usual fail passive ones do not have any rudder actuation by the autoflight system at all.
However if you have a fail operational one it can degrade to the pail passive mode (LAND2) and still provide rollout (which enables lower limits than usual for CAT IIIa), however that rollout mode of course is then fail passive as well.
The fail operational 737 needed a rudder servo and rudder channel in the FCC which meant new FCCs, the usual fail passive ones do not have any rudder actuation by the autoflight system at all.
However if you have a fail operational one it can degrade to the pail passive mode (LAND2) and still provide rollout (which enables lower limits than usual for CAT IIIa), however that rollout mode of course is then fail passive as well.
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No. At least not as standard equipment. You have to buy the fail operational autoflight system option and that includes automatic rollout. The fail operational autoflight system has full rudder authority during the latter stages of an dual autopilot ILS approach, rollout and automatic go around until you select another roll mode.
We did sim training on differences with the CAT 3B NG which was very interesting. The single engine autoland in particular is a neat feature which comes with the package. However the checker emphasised that as the authorisation for our airline is Cat 3A, those are our limits, despite what the individual aircraft is capable of.
Last edited by lederhosen; 10th Nov 2009 at 15:14.
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True, you allways have to respect the limits on your AOC. JAR licences on the other hand just say IR CAT III and that allows all trained for types of CAT III, unlike the old national licences we used to have over here where it stated the allowable limits in the licence.
You are right it does indeed say Cat III. But you can definitely be trained and flying a Cat IIIB aircraft, and still be Cat IIIA limited. Incidentally the rollout feature takes a bit of getting used to. The first time I actually tried it I instinctively tried to put the aircraft back on the centreline. It was tracking straight but a little offset. The aircraft fights you if you try and correct it. Obviously the solution is to disconnect the autopilot...learning by doing!
