Bad piloting? No, bad manuals!

The amateur video is terrifying: a Lufthansa Airbus 320 carrying 132 passengers attempts to land at Hamburg Airport during a storm. Powerful crosswinds force the plane to fly crabwise. As it straightens out just above the runway, the left wing dips sharply and hits the ground:

Fortunately, the pilots gunned the engines, got the plane back into the air, and landed on another runway. But the March 1, 2008 incident could easily have become a tragic accident.

Were the pilots at fault? Was the air traffic controller wrong to have cleared the plane for landing in such high winds? No. The review by Germany’s Federal Bureau of Aircraft Accident Investigation (BFU) came to a surprising conclusion. As reported by the German magazine Der Spiegel, a significant factor was… inadequate pilot manuals.

The Airbus aircraft demonstrated a behavior that had not been clearly described in standard documentation. Airbus, in other words, had left pilots unclear about how the aircraft might respond in this particular situation.

The cause of the incident was a quirk in the Airbus A320’s flight computer. On the first near-landing, it switched to ground mode — which, among other things, limits the power of the ailerons and restricts the pilots’ power to move them. They had to look on powerlessly as the flight computer took control and put the plane at the mercy of the storm…. Only when the pilot started to ascend again did the flight computer return to flight mode and free the aileron.

During the final approach, the tower reported winds gusting at up to 47 knots. The gusts were stronger than the prescribed limit for an A320 — the so-called “maximum crosswind demonstrated for landing.” Taking off again would have been appropriate. But the instructions provided in the manuals offered conflicting information, according to the agency. “We asked 80 pilots how they would have interpreted the instructions,” [chief investigator] Reuss said. “In fact, there were many different interpretations.”

In its report, BFU describes an “insufficient definition and explanation in the flight operations and technical documentation for the operation of the aircraft.” … BFU has ordered the Toulouse, France-based aircraft company to revise its flight documentation to include descriptions that are “uniform, clear and understandable without any contradictions.”

You can say that technical communication helps to ensure the health and safety of users, consumers, and the general public. You can say that technical communicators help reduce risk and liability. Both statements are true. Few examples are more vivid than this one.

You can read the full BFU report here. Thanks to W.C. Wiese for bringing this article to my attention.