Bloomberg is reporting that the helicopter that landed hard during the assault on Osama Bin Laden’s compound was not due to mechanical failure.
Sikorsky (the manufacturer) says that trying to hover over an enclosed area with an 18 foot high wall would have created a vortex of air underneath the helicopter that causes lift of the rotors to dissipate. Temperature may also have played a role.
Wouldn’t you think that Sikorsky might have wanted to mention situations like this in the “OWNERS MANUAL” preferably on PAGE 1 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Who reads manuals?
I live maybe 10 minutes from where they make the Black Helicopters – they’re real! 😉
The area took a big hit after the 2008 election when one of Preident Obama’s first acts was to cancel the replacements for the fleet of Presidential helicopters. It was something like a $10 billion contract – the new ones were going to have every possible defensive counter measure and an indoor basketball hoop. Some other work to upgrade existing helicopters came through – the parking lot at the plant is full and they are the major employer in the area. War is prosperity.
Blackhawk helicopters are equipped with computerized “auto-hover” which keeps the aircraft precisely at programmed lat/lon position and altitude regardless of cross winds or gusts. I’ve seen it in operation during simulated mountain rescue training and it’s amazing to watch.
I do not know if or how the auto-hover system could compensate for vortex buildup on the main rotors due to unusual ground effects. I think the only way to overcome the problem is for the pilot to override the automatic positioning and take the chopper to a higher altitude for hover. The effect would be hard to notice in the dark until it’s too late.