The RAD ALT does a lot more than just the DH as both of them fitted are coupled to the Autoland system to area and activate things like flare & throttle retard modes.
To this end some airfields with CAT2/3 approaches have built radar reflectors in the undershoot to enable a smooth picture for the RADALT to enable it to perform its autoland function.
Cat 2 isn’t autoland
PeteD wrote:
Cat 2 isn’t autoland
Then how those who are not allowed to fly a Cat 2 approach using manual inputs do approach and landing then?
You can have auto-land engaged during approach and once visual for any Cat (also including in sunny days), landing bellow minima without visual clues is a different matter….
Not sure what you are asking? Cat 1 approach can be flown manually or with A/P down to A/P Cat 1 certified limit. The landing is then flown manually.
Cat 2 must be flown with A/P engaged down to DH. It can not be flown manually(as sadly proven in Cork a few years ago) The landing is then flown manually.
All subject to required vis reference at DA/DH
A/P is not the same as autoland.
Haven’t flown cat 3 but there are several types, not all are autoland as I recall
PeteD wrote:
A/P is not the same as autoland
Ok I see the distinction thanks
Autopilot engagement is not always required for a CAT 2 approach if other equipment is available like a HUD, I am told that Air Alaska did CAT 3 on the B727 using just the HUD bit I cant find the reference for this.
Ok, well the aircraft I flew did, (ATP,Q400,Bae146) perhaps you could elaborate on your hud flying experience.
Mine came with one. Never really use it, but have it set at 200ft and do keep it on. It would feel comforting to have on a long over water leg in case some severe instrument failure were to happen where you’d have to descent below weather, fog etc.
Does it work “accuratly” on top of water? with waves?
Radalt with voice call-out became mandatory on public transport helicopters operating over water because of this accident PDF
