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Cat II question

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I notice in the FCOM that when they discuss procedures for CAT II they show image of LAND 2 being annunciated on the PFD. It also states that only one CMD is required. I have experimented with different combinations of Nav radios (both on or only 1 on) and CMD's and I have yet to be able to have LAND 2 display on the annunciator. I understand the parameters of Cat II from RW but it seems counter-intuitive to me to believe that there wouldn't be more protections or redundancies built in for a Cat II setup than for Cat I. When I activate 2 navs and reach 1500 agl (with both CMD's ON) I get LAND 3 annunciated. When I try with just one CMD I get just 1 but never 2. I understand that one such scenario where it would downgrade to a LAND 2 on a full LAND 3 if there were failure before 500 ft agl, but is there a way to set up for CAT II where it will be annunciated as such without first failing in LAND 3? My procedure to fly CAT II as a workaround is just to fly full autoland but disengage AP's at CAT II minimums. Problem is that there are many incidents of needing a CAT II where available but sometimes 2nd Nav needs to be set to a VOR for DME readout if ILS does not have DME.


Craig Williams

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well if you're just wanting to experiment with cat ii, then if you are flying a 737 model with the IFSD installed, you can just hit the reset button, but thats not normal procedure.


Bryan Richards

 

"People depend so much on automation that they forget how to get the automation to work." B.W.

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As you said, the Land 2 annunciation is when a Fail Operational autoland encounters a failure.It will still make a full autoland with flare and rollout. To see Land 2 announced just set the IFSD to fail and do an autoland.It will announce Land 2 instead of Land 3. You cannot do any type of autoland with only one autopilot. It's worh noting that you can do an autoland at any airport in FSX provided it has an ILS.FSX airports no nothing about Cat 1, 11 111.


Frederic Steiner.

B7382.jpg

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Thanks, Fred. How did you handle a RW CAT II situation where you needed second Nav radio tuned to VOR for DME? FCOM does refer to CAT II procedure with only one CMD (but CAT II is not really autoland it is just auto-coupled isn't it since AP is disconnected at minimums and manual landing is used?). Point is that 2 CMD's will not connect unless BOTH navs are tuned to ILS freq/course and if ILS does not have an incorporated DME then...?.


Craig Williams

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As fred said, CAT 2 is only used when theres a failure of a system that prevents CAT 3, so it will revert to CAT 2 automatically, if you want to force a CAT 2, simply hit the RST button on the ISFD, you can do a CAT 2 approach with only 1 autopilot but must be disconnected at DH, you can also do a CAT 2 Autoland, but regulations require that to be a "see to continue" rule, where runway/lights must be seen at DH.


Bryan Richards

 

"People depend so much on automation that they forget how to get the automation to work." B.W.

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As fred said, CAT 2 is only used when theres a failure of a system that prevents CAT 3, so it will revert to CAT 2 automatically, if you want to force a CAT 2, simply hit the RST button on the ISFD, you can do a CAT 2 approach with only 1 autopilot but must be disconnected at DH, you can also do a CAT 2 Autoland, but regulations require that to be a "see to continue" rule, where runway/lights must be seen at DH.
CATIII =/= LAND 3. One is an approach type, the other is an autopilot annunciation for a Fail Operational A/P.
How did you handle a RW CAT II situation where you needed second Nav radio tuned to VOR for DME?
Do you have example?

Matt Cee

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I understand the difference Matt. Sorry for my confusion of terms in my post. The question was answered: how to get the PFD to annunciate LAND 2. I was used to the Level D where the selection of CMD's determined the type of approach available. But thank you for your input. Also want to thank Brian for his concise and correct answer. That was what I had assumed but there are so many new and sophisticated systems on this NGX that I just wanted to make sure I wasn't missing something.


Craig Williams

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