DA, DH at decision point....
03-04-2008 | 08:20 PM
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From: ATP, CFII, MEI, Chief Flight Instructor, Charter Captain CE402, CE421, BE58
DA, DH at decision point....
I had this discussion with our chief pilot today. To be honest, I had never really thought about it this way. He posed the question, for checkride and training purposes, is it a bust or inappropriate to descend below DA at the point a missed approach is executed. Now we are just talking about 10 or 20 feet as the missed approach is executed, because a descent is imminent transitioning from your flight profile. Any thoughts would be great.
03-04-2008 | 09:00 PM
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From: 767A (Ret)
Tolerances
Our simulator checkride standards allowed for a slight (inevitable) descent below DA/DH, so long as the missed approach was initiated exactly at the DA/DH.
For a non-precision, the MDA was supposed to be a "hard" altitude, but when pressed for more guidance, instructors said they had a tolerance of up to 100 feet above the MDA and zero below it when reaching the VDP. If you were in this "window" and he wanted you to land, you would see the runway in time for a normal descent.
For a non-precision, the MDA was supposed to be a "hard" altitude, but when pressed for more guidance, instructors said they had a tolerance of up to 100 feet above the MDA and zero below it when reaching the VDP. If you were in this "window" and he wanted you to land, you would see the runway in time for a normal descent.
03-04-2008 | 09:19 PM
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From: ATP, CFII, MEI, Chief Flight Instructor, Charter Captain CE402, CE421, BE58
We agree completely on the MDA being a "hard" altitude. That is exactly what he was talking about , a "slight" and inevitable descent below DA/DH.
Because that is the altitude where the "decision is made".
thanks
Because that is the altitude where the "decision is made".
thanks
03-04-2008 | 09:38 PM
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From: ATP, CFII, MEI, Chief Flight Instructor, Charter Captain CE402, CE421, BE58
The only thing I can find in the FARS is actually in P/C glossary under the definition and it really doesn't help much. I'm planning on talking to a couple of our local examiners and seeing what they're thinking.
03-04-2008 | 09:41 PM
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From: A320 CA
Think about it...if ILS DH was a hard altitude, then it would be theoretically impossible to shoot an ILS to mins since you would have to start leveling off which would put you high on glideslope by the time you reach DH. The answer is in the names.
03-04-2008 | 10:13 PM
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From: C-130
The wording is you may not "continue the approach" below DA/DH if certain criteria are not met (approach lights, etc), if and when you hit DH and do not see the runway, you are not "continuing" below the DH, you are now "executing" a missed approach...
separate from MDA which says you may not "operate" below MDA
separate from MDA which says you may not "operate" below MDA
03-05-2008 | 11:29 AM
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From: Fixed wing, left
Another question comes to mind. Lets say you start to
"execute" the missed approach and you drop 20-30 feet below the DH. At that point you see the approach lights or thresh hold or whatever. Do you continue the missed or cut the power and come in for a smoooooth landing?
"execute" the missed approach and you drop 20-30 feet below the DH. At that point you see the approach lights or thresh hold or whatever. Do you continue the missed or cut the power and come in for a smoooooth landing?
03-05-2008 | 12:33 PM
#10
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From: Engines Turn or People Swim
Another question comes to mind. Lets say you start to
"execute" the missed approach and you drop 20-30 feet below the DH. At that point you see the approach lights or thresh hold or whatever. Do you continue the missed or cut the power and come in for a smoooooth landing?
"execute" the missed approach and you drop 20-30 feet below the DH. At that point you see the approach lights or thresh hold or whatever. Do you continue the missed or cut the power and come in for a smoooooth landing?
Descent below DH/DA is inevitable on an ILS to mins, unless you call missed above DH/DA for some reason. It is normal, expected, and happens all the time.
For CAT II and better, you can expect to possibly touch the runway with the mains while executing a missed.
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