German investigators believe that lack of clarity over crosswind operating limits contributed to a Lufthansa Airbus A320's suffering a serious wing-strike while landing at Hamburg two years ago.
Analysis of the incident - particularly the decision to continue an approach despite strong gust conditions - has revealed discrepancies by pilots in the interpretation of crosswind limits as presented in operating manuals.
Flight LH044's left wing-tip was damaged after it struck the surface of runway 23 when the A320 suddenly rolled to the left just as it touched down. The crew executed a go-around and subsequently landed safely.
German investigation agency BFU, in a final report into the incident today, states that the crew had opted to make the de-crabbed approach after being informed that winds were at 28kt, gusting to 37kt.
Airbus' A320 flight crew operating manual, under the term 'maximum crosswind demonstrated for landing, gives a figure of 33kt gusting to 38kt.
During LH044's final approach, however, the crew was told that the winds were still around 28-29kt but gusting to 47kt.
BFU says that a go-around would have been "reasonable", but states that the crew "did not interpret" the operating manual information prescribing a limit for the aircraft.
Concerned over the possible lack of clarity regarding operating limits, the investigators questioned 81 pilots from five carriers to understand how the term 'maximum demonstrated crosswind' is interpreted in practice.
The survey found that while half of respondents viewed the term as a limit, the other half considered it only a guideline.
BFU says this is "evidence of a considerable information deficit", adding that the terms used in the operating manuals - and by the carrier itself - are not adequately defined or explained.
"The answers to the questions on the permissibility of landings in gusty conditions call for clarification," it says.
Among 12 recommendations in its final report into the 1 March 2008 incident, BFU has recommended revisions to the nature of the crosswind information presented by Airbus in its operating manuals. It also says that airlines should set crosswind limits for their own specific operations.
