Originally Posted by
DaveReidUK
You change the whole unit (pictured here) - the ramp is not the place to start taking it apart.
https://www.youtube.com/watch?v=waYos1ftm98&t=40
Eight screws, gasket, two electrical connectors, probably less than an hour including functional checks.
I'd be fascinated to know how the unit that was removed subsequently tested on the bench. Since I'm in a betting mood, my money would be on NFF.
As would mine...
Which raises the question: “What post-replacement functional checks are called for (in the AMM), and what functional tests were actually performed after the replacement probe was installed?”
If the AMM calls for fitting a calibrated AOA protractor to the probe and fuselage to verify correlation between probe position and transmitted AOA data, and that was not done - either because of lack of time, lack of test equipment, or lack of training, it’s a serious problem.
I would hope that Lion Air maintenance didn’t just slap on a new probe, ignoring any required correlation tests on the assumption that the original probe itself was bad.