A320 D-AXLA, from Bjorn (Creative Commons).

Eddie Sez:

There are few things more dangerous than an airline crew on a non-revenue flight, where crews that are normally tightly controlled are unbounded and given an airplane with almost no supervision and no one in back to complain. But one way to make that dangerous situation even more so is to give that crew the responsibility for a functional check flight.

This crew was given an airplane that had been recently painted and washed, leaving their angle of attack systems corrupted, and this would make their Airbus A320 behave differently than they would expect under "normal law." For a primer on understanding how an Airbus flies, see: Basic Aerodynamics / Airbus Control Laws.

The next problem was they didn't have formal training or a specified test procedure to follow, encouraging them to improvise. The result was a low altitude stall that wasn't survivable. The lessons write themselves: Normal Procedures & Techniques / Functional Check Flights.

What follows is from the relevant accident reports and other documents, listed below, as well as my comments in blue.


Accident Report


Narrative

[BEA, ¶1.1]


Analysis

[BEA, ¶1.6.6.]

[BEA, ¶1.17.8.3.] Crew training for check flights

[BEA, ¶3.1]


Probable Cause

[BEA, ¶3.2]


See Also

Basic Aerodynamics / Airbus Control Laws

Normal Procedures & Techniques / Functional Check Flights


References

Bureau d'Enquêtes et d'Analyses (BEA), Accident of 27 November 2008 off the coast of Canet-Plage (66) to the Airbus A320-232 registered D-AXLA operated by XL Airways Germany.