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CAT lll b HUD usage and Approach ban

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CAT lll b HUD usage and Approach ban

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Old 7th Nov 2019, 16:58
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tae9141
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CAT lll b HUD usage and Approach ban

Hey guys,

I am doing my initial 737 training and just did my CAT 2/3 check out on FFS few days ago.
From the debrief, my instructor mentioned few things that I need to dig in and find out the reference, and they are HUD usage and approach ban.
He mentioned that the HUD cannot be used during CAT lll b for 737MAX and I cannot find out the reference where it states such limitation on pilot.
Also, mentioned that the approach ban does not apply to CAT lll but CAT ll and below.

Not sure if he is strictly sticking to the ICAO operation or regulation in some other country, as he has been around the world for many years, I would appreciate your comments and ideas !

thanks.
 
Old 7th Nov 2019, 18:25
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Don't know which part of the world you are flying in, but here in EASA land, approach ban very much applies even for Cat 3 approaches.
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Old 7th Nov 2019, 19:30
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Back when we were still operating them, we were told the MAX's were limited to Cat II until they had accumulated enough history in operational use. I think it was an op spec issue and not necessarily an ICAO/FAR limitation. Sorry, don't have a reference.
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Old 8th Nov 2019, 07:37
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Originally Posted by tae9141
HUD cannot be used during CAT lll b for 737MAX and I cannot find out the reference where it states such limitation on pilot.
It's not merely MAX limitation, HGS (as any other fail passive, no automatic rollout system) is limited to DH50/200m of Cat 3a no matter the airframe it's attached to. Having flown a few actual RVR 200 HGS approaches, I'm glad it is so - I would have been quite lost without flare cue and rollout guidance and seeing even less CL and TDZ lights would be too scary for comfort.

As for approach ban, I can't find any reference that the CAT III differs from other IAPs. My instructors' favourite scenario during sim cat 3a practice is giving less than 200m RVR with approach clearance (allowed to commence approach), report it's 200 before 1000AGL (allowed to continue approach) and afterwards report it's below 200 again (now allowed to descend to DH). Actual rules may vary depending on the country/operator.
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Old 8th Nov 2019, 11:55
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Originally Posted by tae9141
Hey guys,

He mentioned that the HUD cannot be used during CAT lll b for 737MAX and I cannot find out the reference where it states such limitation on pilot.
After re-reading your question, I believe what your instructor was referring to is that the HUD is a "fail-passive" approach system, as opposed to "fail-operational", and thus limited to CAT IIIa operations. See FAA Advisory Circular 120-28C for further details.


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