Ask Captain Lim

Dear Captain Lim,

Do tell me, in the event of severe weather, say a typhoon like the one that crashed an MD 11 in Hong Kong, which aircraft would fair better? The Boeing 777 or the Airbus A340? You would think that, with 4 engines - stability is better on the A340. What if the Boeing 777*s engine stops working? Will there be drag enough to flip the plane over?

Also, another question would be, can these planes do a flip and still hold structural integrity? Are the planes designed to flip on its belly and flip back up, say in a severe cross wind or malfunction? Which plane would fair better? ...Bias is ok.

Tom Cal

Hi Tom,

I cannot tell you precisely which airplane fares better in a flip over when encountering severe weather. A nasty accident can happen on either of them. Whether it would or would not flip over would depend on many factors. These can be due to the severity of the crosswinds, skill and experience of the pilot, the airplane*s configuration and a whole lot of unforeseen circumstances.

Yes, the airplane model could also be a factor. For instance, during a landing incident at Newark International Airport, USA, an MD-11 crashed on July 31, 1997. The aircraft flipped onto its back and subsequently burned following a landing attempt from an unstabilized flare. This was followed by a similar accident when another China Airlines MD-11 crashed while landing at Hong Kong airport during a typhoon - also flipping onto its back and was partly burned. The Boeing 777 or Airbus A340 has not exhibited such a tendency yet as they have better stability during strong crosswind landings.

An engine failure on the Boeing 777 would not cause the plane to flip over. It would merely induce a yaw and a slight roll towards the dead engine but this would be quickly taken care of by the TAC (Thrust Asymmetric Compensator) and the pilot. So, no big deal at all!

Are planes designed to flip over and back up in severe crosswind? Oh dear, not that I know of as far as commercial planes are concerned! What I can say is that, modern airliners are built to be structurally very robust. Go to a previous FAQ where you can see on YouTube that the Boeing 777*s wing was bent up to 24 feet before it broke. A flip over on a commercial airplane is a very serious and dangerous maneuver when close to the ground. Only military planes are capable of deliberately doing so!

Let me recall the MD-11 accident at Hong Kong. On 22 August 1999, the plane was making its final approach when a typhoon with maximum reported wind speeds of around 73 knots (85 mph) was in the vicinity of the airport. At 700 feet prior to touchdown, the wind was 320deg/28 knots gusting to 36 knots. Even though the plane crosswind limitation was 24 knots, the pilot neglected this limit and continued with the landing. During the final flare to land, the plane banked on its right, landed hard on its right main gear and the right engine touched the runway. The right main gear and the right wing separated. The plane rolled upside down and skidded off the runway in flames. (Only 3 passengers died out of the 300 onboard. The final report blamed it mainly on pilot error)

So this was not really a flip over in the right sense of a flying maneuver but rather, the plane rolled upside down partly because its right wing snapped as a result of the very hard landing!

Which plane would fare better in a flip over? Yes, I am not going to be bias towards the Boeing 777 this time as I am now flying the Airbus, not the A340 though, but the A320 :-) Both the Boeing 777 and Airbus A340 are designed to be very stable and would resist any tendency to roll and flip over in a normal flight.

So, I believe, both would fare equally well and would hold structural integrity in an unlikely event of a flip over. Anyway, it is difficult to make a good comparison, as any damages would depend on the force of the impact.