AF 447 Thread No. 8

[PJ2]

bubbers44;

Your neighbour's confusion over this checklist seems to be common among many Airbus and even non-Airbus pilots.

The Airbus Flight Crew Training Manual specifies that if the safety of the flight is not at immediate risk then the memorized items are NOT to be followed. Instead, the aircraft is to be leveled off for troubleshooting once above the MSA or circuit altitude, which FL350 certainly is.

"Immediate Risk" is not specified in the checklist but it is specified in the training associated with this checklist in an Airbus document which I posted the link to some time ago.

I have maintained for a very long time that it is this confusion and some recent low-level training (UAS event right after takeoff) that triggered AF447's PF to increase the pitch attitude of the aircraft because it was the only thing he could recall in this confusing and poorly-designed memorized drill and checklist.

The series of "if-then" statements in the memorized items do not apply to cruise altitude events where the safety of the flight is not at immediate risk. The loss of airspeed information is not an emergency and it is not a high-risk event which demands immediate action. Your response is precisely the one that should have occurred on AF447 - maintain level flight through pitch and retain the power settings which existed just before the event, while the PM gets out the QRH to fine-tune the pitch and power settings. In other words, do nothing with the pitch and power if they were suitable prior to the event. Things aren't going to change that much while the QRH is retrieved and read.

You argue correctly with your Airbus pilot neighbour but it is not his fault that he is confused, and, I submit, this and the low-level training the PM and PF had recently received are factors in this accident. How much is for the BEA to determine but I believe at least one pilot, the PF, was psychologically "primed" by the low-level UAS event which is the only UAS event training he had received.

In re RVSM, one does what one must do in an emergency of course but a thousand feet is nothing for the airplane to gain or lose so I think your point is a very good one to consider.

All that occurred after the apogee of the pitch-up and stall are far beyond transport pilot experience and territory and it is questionable whether anyone could sort out what this crew faced, after the AoA had exceeded 30deg in the "flat-plate" descent.

I have discussed this at length on all these threads, with graphics if you wish to examine this further.

Over the past year or two others here have disagreed with this assessment, and stated that above FL100, a 5-degree pitch-up is required by the UAS memorized drill regardless of altitude.

While I heartily disagree, (primarily because I think the FL100 case caters to high altitude airports and not 10,000ft above the local ground where the safety of the flight is not likely threatened by a UAS event, and a pitch of 15deg at, say, Bogota risks losing energy for obvious reasons whereas 5-deg is certainly safe enough in the initial climb until above the local MSA), the airplane will not suffer a swift and severe loss of airspeed in a 5-deg pitch-up, (I once said it would but was wrong), with an added 2.5deg pitch to the cruise pitch attitude of about 2.5deg, although it will slowly lose energy/airspeed.

But the FCTM specifically states that when/if the memorized items are accomplished by the crew, a very quick response using the QRH pitch and power settings is required to prevent an overspeed.

There is the admonition/warning to the crew in the FCTM and the schematic diagram therein which illustrates how to do this drill and checklist, to always respect the stall warning in a UAS condition.

Your Airbus pilot neighbour is wrong in his views on how to handle this event. One simply does not de-stabilize an airplane at cruise altitude without very good reason, (such as avoiding a greater danger). Pitch and power were suitable prior to a UAS event and should serve perfectly well for the few moments it takes to get out the QRH tables to fine-tune these settings. It is essentially a non-event. It may be disturbing but that is why we are thoroughly trained every six months or so...to reduce surprise and the degradation of cockpit discipline and the forgetting of SOPs.