Originally published at: FAA Proposes Fix For Freezing 737 AOA Sensors
Proposed AD follows false stick-shaker events traced to frozen sensor vanes on MD-90s.
This reminds me of my time working on F35 design. The LMCO baseline was to have all air fat port heater to be controlled by the pilot.
Which means the pilot can forget to turn them on. My proposal was to have them powered on with a controller to keep the air fat port from overheating. Cheap easy no pilot workload.
Overeuled until a B2 was destroyed by this exact problem of ice in an air data port.
Any flight critical item that can ice up should have a fully automated heating system w a feedback to the master control software to assure safe operation prior to flight. Cheap easy no pilot work load keeps peole alive.
Pray tell who is still flying the MD-90? NASA?
Boeing’s 737s had a green light for each pitot and static heater system, until an incident. I forget details of the switch of power.
Changed to orange, lit up if heat was off.
Ah, heating pitot and static systems is a challenge.
As Airbus discovered with AF447 high over the south Atlantic.
Airbus switched to the pitot tubes used on Boeing 707 and 727, which had extra heat because of an incident high over south Pacific. (Flight crew recognized airspeed was inaccurate so used other ways to monitor speed including IIRC Doppler navigation system.)
(I don’t know if the change was near enough to keep AF447’s airspeed system from freezing but it should help.)
I know of an airliner system that had extra heater wrapped around line from static port.
This topic was automatically closed after 7 days. New replies are no longer allowed.