Archive for March, 2009

Wake Turbulence Again? Maybe not.

Wednesday, March 4th, 2009

Last week’s crash of a Turkish Airlines 737-800 landing in the Netherlands has everyone speculating on what might have happened. Wake turbulence from a Boeing 757 that is rumored to be the preceding aircraft, is one of the theories. The weather doesn’t appear to have been an issue with one possible caveat. Light winds can cause wake to hang for a long time and turn a no-brainer approach into a real head banger.

Based on sketchy reports at this time, only two minutes elapsed between aircraft when witnesses said the 737 came ” ‘straight down.” Reliable witness reports are often an oxymoron so, as usual, we’ll be waiting to see what the real deal is. The 757 is known to have a particularly strong wake and while it technically isn’t classified as a heavy, maybe it should be treated as such. ATC does allow extra spacing after these aircraft but perhaps it wasn’t enough, even for a big aircraft like the 737.

We discussed wake dangers as recently as November Rolled involving a Learjet in Mexico and if that were to be the cause again here, take it to heart that below and behind is not a good place to be. With the recent spate of air carrier crashes (USAir in the Hudson with a total power loss, Continental in Buffalo possibly due to icing and now a possible wake encounter, it’s worth remembering that the basics of flight apply across the board – doesn’t matter what you’re flying.

Late breaking news – now it appears that a misreading altimeter caused the autothrottles to think it was time to flare and land. They reduced power to idle and by the time the crew caught it, the aircraft was out of airspeed. I’ll reiterate the last sentence – it’s worth remembering that the basics of flight apply across the board – doesn’t matter what you’re flying. Also shows the danger of speculation.