Near Collision at BOS between Aer Lingus and US Air

[AMF]

M. Mouse......

There's nothing arbitrary and no need to be disturbed....I readback everything except in those rare circumstances where the controller himself is not requiring them, if I'm interrupting his dialogue, or it's clearly irrelevant and doing so will either prevent me from staying ahead of the airplane or divide up cockpit duties in such a way to be detrimental to safety in a critical phase of flight...such as 3 miles past the point of being told to contact tower by appch because the freq is too jammed to do it (at that point, you don't want two pilots working 2 different freqs on short final, one who is flying the airplane). That defies logic.

Stu.....

Thanks for the link. You'll notice in Incident 5 that the crew's readback interrupted the controller's transmission so the controller never heard it. Mis-hearing the clearance and reading back a too-low altitude didn't avert the CFIT. No doubt the crew interpreted the controller's silence to their assumed-to-be-transmitted-and-heard readback as affirmation, and re-inforced in their own minds what was unfortunately a mistake.

The unfortunate irony is that it was the quick-draw readback transmission itself that interrupted the controller's re-iterated critical instruction....."report level at three thousand feet".

The glaring difference with that incident and what I've been saying is that the CFIT took place in a NON-radar environment. I specifically refered to under radar control, where the controller observes your compliance.

Non-radar, that crew should have picked up on their own interpretation error, given that they thought they heard clearance to a lower altitude than what their charts/plates would have indicated was allowed when established on a route/arrival/approach. In that case we're wholly responsible for our own survival when it comes to avoiding terrain, and that means adhering to min altitudes and staying established. Instead of reading-back in that case, they should have noted this conflict and queried the controller. Unlike a mere readback such as they gave, a controller's silence in response to a question will generate more questioning. And of course, descending before sorting it out is always out of the question.

The controller didn't query the apparent (to him) lack of a readback by the crew. I specifically indicated in a previous post that in a non-radar environment readbacks are indeed the best tool for the controller raise the probability of compliance and that communication took place. Unlike all the examples given by others regarding ORD, NYC, etc....that controller was blind, and therefore should have indeed queried the crew. No disagreement there.

However, the main causal factor was mis-hearing the clearance, and it only serves to highlight that BOTH pilots must focus and maintain a disiplined listening watch, and confirm between themselves they heard the same thing. This is essential, and of paramount importance because "T-ing" until you're blue in the face doesn't make up for sloppy CRM where both pilots don't hear and confirm between themselves.

In this accident the controller DID issue the correct instruction after all, and the main breakdown leading to this CFIT wasn't R/T dicipline, but lack of CRM and situational awareness.