Failure analysis

Circumstances

Habsheim aerodrome was too small to be listed in the aircraft's flight computer, thereby requiring a visual approach; both pilots were also unfamiliar with the airfield when they began their descent from 2,000 feet only 6 nautical miles (11 km) from the field. This distance was too short for them to stabilize the aircraft's altitude and speed for the flyover.

Latent hazard

The accident was due to human-machine mismatch, namely, operating in a latent exceptional situation .

• The aircraft was operating in the exceptional "Protection envelop" state
• The operators (pilots) were no aware of this state.

Design mistakes

The sources for this misfortune were:

• The design enabled the operators to change to the state, with which they were no familiar
• The design did not provide alarms about the aircraft being in the exceptional situation.

  Guidelines about rules defining proper human-machine coordination, and keeping with the rules

  Guidelines about assuring the operator's awareness of the system situation

Sources for the design mistakes

The operational rules were implicit. The design did not constrain the aircraft to operate according to safety rules.

• The design did not provide means to set the primary operation modes. Therefore, there were no means available enabling decide whether flyover should be prohibited, or treated as exceptional.
• Because the design did not enable identifying the exceptional situation, there was no way to provide the alarm when it was required.

  Guidelines about the alarm design

  Guidelines about protecting from operator's mistakes

Updated on 20 Apr 2016.