So What Happened in Hamburg in March 2008?

The weather in Hamburg was nasty on March 1, 2008. It was nasty pretty much all over Europe. LH 44, an Airbus A320, was en route from Munich to Hamburg during the storm "Emma" when it tried to land at Hamburg's Fuhlsbüttel airport in strong crosswinds. Seconds before touch down, the Airbus was hit by a strong gust of wind and its left wingtip made contact with the rundway, causing the pilots to go around. The plane landed without any problems a few minutes later and nobody was injured. However, thousands of people who watched the video online or on TV have been asking themselves what happened here? Was it the pilots' fault? Was the wind just too strong and should they have shut down the airport during the storm? Was there a problem with the fly-by-wire system? Last week, the German Federal Bureau of Aircraft Accident Investigation (BFU) issued its final report on the accident.

But before I summarize the report's key facts, you should watch the video again:



Initially, people praised the pilots for their "heroic" reaction. They pulled the plane back up and, consequently, avoided a crash. Then, experts started to doubt this version and asked why the pilots didn't use a different runway at the airport in the first place, one that was better suited for landing in strong winds? And why was the 24-year old, inexperienced co-pilot flying in such bad conditions and not the captain himself? Finally, Airbus's fly-by-wire system was blamed for causing the accident. By switching to "Ground Mode" when the plane's first pair of tires hit the runway, the system didn't allow the pilots to fully control the plane anymore - it limited the inputs the pilots could give via the sidesticks, which prevented them from leveling the wings again quickly.

The BFU's report offers some interesting insight into what really went wrong on March 1, 2008. First of all, the crew was well trained to land the plane in weather conditions like those present on this day in the spring of 2008. Even the 24-year old co-pilot had adequate training to land the A320 in strong crosswinds and the captain is not to be blamed for letting her land the plane. He took over control as soon as it was clear a go-around was necessary. However, the cockpit crew is is still at least partly to be blamed for this accident. They knew that there were crosswinds with gusts of up to 55 kts and they still decided to land on one particular runway that was not the wisest pick under the given conditions. Also, the A320 is only approved for crosswinds of up to 38 kts. The cockpit crew should have been aware of that. The BFU report states that most pilots are not aware of the crosswinds limits and the BFU blames Airbus and Lufthansa for not communicating those limits clearly enough. I think this is pretty ridiculous, since even I know that there are limits for landing a plane in crosswinds and I am not (yet) a pilot. So this is a pretty lame excuse.

Another factor here was the impact of Airbus's fly-by-wire (FBW) system. As soon as an Airbus plane touches the runway with one of its tires, the FBW automatically switches from "Flare Mode" (which is operating during the approach) to "Ground Mode" (which applies when a plane is on the ground). During Flare Mode the pilots are allowed to give inputs within the entire scope of permissible commands, during Ground Mode this is no longer the case. But why did Airbus design the FBW to switch into Ground Mode before at least all of the tires in the rear of the plane touch the ground? Well, the reason for this is: Airbus wants to prevent pilot-induced oscillation shortly before the plane touches the runway, which is actually pretty smart. This means, the pilots' controls over the ailerons are very limited when the system switches to Ground Mode. Ironically, this was implemented to prevent the plane from hitting the ground with its wingtips. In this specific instance, however, it caused some trouble, since the plane didn't react to the pilots' inputs and the FBW took over control for several seconds, leaving the pilots with very limited control over the plane. The only option for them was: Get the plane to switch into Flare Mode by increasing speed and taking off again. However, the pilots said they were not aware of these Ground Mode limitations either.

To summarize this: In the end, several factors contributed to the accident. I have to say though that this was not as severe as some people and the media made it look like. This was not an "almost crash" at all. There was some minor damage to the plane, but it absolutely didn't render it uncontrollable. The first factor was: The pilots landed in crosswinds that were too high for the A320 and they should have known that. However, they didn't. I blame Lufthansa more than Airbus. Lufthansa should inform all their pilots about crosswind limits for all its planes. Second, the crew didn't choose the best runway for the wind conditions. They should have chosen the runway they used for their second (successful) landing attempt in the first place. Third, pilots have to be aware that Airbuses switch into Ground Mode as soon as one tire hits the runway. It wouldn't have helped in this case, since there was nothing they could have done, but at least it wouldn't have been a surprise.

Should Airbus change their FBW system and make it switch to Ground Mode only after the tires on both sides touch the ground? Absolutely not! This was probably the first time an accident happened because of the FBW during landing in crosswinds. I am sure it has already prevented dozens of accidents in the past.