05 January 2008

Another Way To Bend A Helicopter

It's always easy to second guess, but I think this video shows a phenomenon that every basic helicopter student is taught to avoid:



My guess?
I'd bet "settling with power", or more correctly, Vortex Ring State, where the air being pushed downward by the rotor system recirculates around the rotor and becomes accelerated enough that the rotor can no longer push itself upwards using that recirculated air.

Recognized quickly, the disaster is avoidable.

8 comments:

elay said...

that was one rapid descent..tsk..tsk..

thanks for the video..i played it over and over again. it also had me going over a review in my head of the aerodynamics of rotary wing..

The Old Man said...

Your video didn't like me and wouldn't play. I thought I was the one that didn't play well with others....

cary said...

That hurt, just looking at it. Was everyone OK or did they end up inside as patients?

I cringed just watching it come in so fast.

Greybeard said...

I don't know the answer to your question, Cary. I can't even tell ya what country this happened in.
But at the end of the video you can see the helicopter on it's side, "living space" intact... a positive sign for those inside. You're likely looking at spinal injuries, but I suspect the worst danger was to those outside watching/recording, having to dodge pieces of rotor blade coming at them at 300 miles per hour.

Anonymous said...

http://www.ntsb.gov/ntsb/GenPDF.asp?id=DEN05FA103&rpt=fa

very sad.

--sarah

Anonymous said...

Whoops, sorry got the wrong report link.

A better outcome:
http://www.ntsb.gov/ntsb/GenPDF.asp?id=DEN02LA010&rpt=fa

Oshawapilot said...

Interesting you should post this - although I fly only scale aircraft, I do fly RC (Radio Controlled) heli's and only yesterday had someone ask me if settling with power was possible in RC.

It is - I've seen it happen, usually to students with a habit of descending through their own vortex when landing after practicing higher level flight.

In RC it often goes unrecognized since it's not well understood and just blamed on an uncontrolled decent, or poor collective management on approach.

Greybeard said...

Clickable link to the accident report is here. Note the aircraft total time... 40 hours!
Also surprising... 9 November 2001.