SearchSearch 

Air Crash Investigation

Pro Member Captain
Doyley Captain

For anybody that is interested and has National Geograpic there is a Air Crash Investigation day today 😀

I love this show, really interesting!

15 Responses

Pro Member Captain
Doyley Captain

While we're on the subject of aircraft investigation, what hapens if a helicopter has an engine failure? Is it totally screwed?

Pro Member Chief Captain
pilotwannabe Chief Captain

Just watched the one where a US navy ship shoots down an Iran Air A300 by accident. By the way I read once that if a helicopter loses its engine its not the end of the world because as the copter falls the air resistance or something like that rotates the prop and so it glides down to earth 😀

Pro Member Captain
Sean (SeanGa) Captain

I am afraid that is wrong - that only applies for ACKD23 helicopters... with regular helicopters, the pilot has a stick in the ceiling so he can rotate the blades manually.. sometimes if he's lucky and has a passenger on board, the passenger can help if the pilot get's tired. Now you probably understand why helicopter pilots have to be very strong, just like me. yep

Pro Member First Officer
simon roourke (simon123) First Officer

I have it seen em all. Like to see new ones. But let’s not forget people die sometimes. 😞

Pro Member Captain
Doyley Captain

Yeah unfortunatly this will always be a part of flying and any other form of travel 😞

Pro Member Chief Captain
hinch Chief Captain

just watching a 747 blow a citroen 2cv about 200ft in the air...i love top gear (uktv people)

'if these engines run at full thrust for more than 20 seconds, they start to rip up the tarmac'

Pro Member Chief Captain
CRJCapt Chief Captain

If a single engine helicopter has an engine failure, all is not lost. It is designed to glide to a landing similar to an airplane but at a much steeper angle. There is a mechanism installed between the engine and the transmission that automatically disconnects during an engine failure allowing the main rotor blades to spin freely as the aircraft descends through the air. This is call Autorotation and allows a distressed helicopter to land almost normally, most times more firmly, in event of an engine failure. 🙂

http://en.wikipedia.org/wiki/Autorotation

Pro Member Chief Captain
Greekman72 Chief Captain

CRJCapt wrote:

If a single engine helicopter has an engine failure, all is not lost. It is designed to glide to a landing similar to an airplane but at a much steeper angle. There is a mechanism installed between the engine and the transmission that automatically disconnects during an engine failure allowing the main rotor blades to spin freely as the aircraft descends through the air. This is call Autorotation and allows a distressed helicopter to land almost normally, most times more firmly, in event of an engine failure. 🙂

http://en.wikipedia.org/wiki/Autorotation

Excellent and clear explanation. 👍 👍 👍 Clap

Pro Member Chief Captain
CRJCapt Chief Captain

Thanks, Greekman. 🙂

Pro Member Chief Captain
Greekman72 Chief Captain

CRJCapt wrote:

Thanks, Greekman. 🙂

We have to thank you for sharing with us your rich knowledges about aviation. Bow Down

Pro Member Captain
Doyley Captain

Excellent, I fell better knowing that 😂

Thanks very muchly 😀

Pro Member Chief Captain
pilotwannabe Chief Captain

CRJCapt wrote:

If a single engine helicopter has an engine failure, all is not lost. It is designed to glide to a landing similar to an airplane but at a much steeper angle. There is a mechanism installed between the engine and the transmission that automatically disconnects during an engine failure allowing the main rotor blades to spin freely as the aircraft descends through the air. This is call Autorotation and allows a distressed helicopter to land almost normally, most times more firmly, in event of an engine failure. 🙂

http://en.wikipedia.org/wiki/Autorotation

well, thats a better explanation than mine 😀

Pro Member First Officer
Canyon (NoWorries) First Officer

CRJCapt wrote:

There is a mechanism installed between the engine and the transmission that automatically disconnects during an engine failure allowing the main rotor blades to spin freely as the aircraft descends through the air.

Good explanation. The "mechanism" is called a FreeWheeling Unit, and it doesn't automatically disconnect, it isn't that complicated(if it were, it wouldn't work). Pretty much the freewheeling unit is a rachet(albeit better machined than the craftsman type), so if the engine is applying power to the rotor blades, it locks(like tighting a bolt), but if the rotor blades are applying power to the engine, the freewheeling unit just clicks(although there is no actual clicking).

The freewheeling unit is between the engine and the rotor blades, while the engine is between the main and tail rotor blades, so if the engine siezes, it WILL stop the tail rotor. The way that engineers get around this is by putting a HUGE verticle fin on the back of the helicopter, so in the chance of an engine failure, the helicopter needs at least 25 knots of forward speed, so the fin will trim the counter-rotation from the rotor blades, which is why the rails a helicopter sits on are called, "Skids". 🙂

A helicopter must be tested for its autorotation effects at least every 100 hours. Usually you just take the engine to idle, but I have been in one autorotation where the pilot completely shut down the engine...it's pretty weird to be sitting in a craft that usually makes 120 dbls and all of the sudden it's quiet. The test is called the "Down-turn" check, and the blades should spin between 101-107% rpm, if they spin faster or slower, it is necessary to adjust their 0-collective pitch.

Lastly, if you want to try to autorotate an FS helicopter, you have to keep collective at about 10%, which is totally wrong...in a real helicopter, in order to ensure proper autorotation, collective should be all the way down.

And now you know. 🙂

Pro Member Chief Captain
Tailhook Chief Captain

Roger that. - Now, have you got a favourite Huey for fs9? One that comes with a link maybe?

Pro Member Chief Captain
CRJCapt Chief Captain

My post above was a simple answer to a simple question without getting technical. I see more detail is needed.

In reference to the Jet Ranger helicopter in the picture:

1. By "automatically disconnecting" What I mean is , no pilot action is required for the function.

2. The freewheeling unit in mounted between the engine accessory gearbox and the transmission and connected by the main driveshaft. The main rotor blades are connected to the transmission via the main rotor mast and main rotor hub assembly, it's controlled via swashplate assembly and pitch change links.

3. The vertical stabilizer requires approximately 40-70 knots to be effective in the case of loss of tailrotor effectiveness. There are certain malfunctions that cause the tail rotor to stop rotating but I was talking about a simple engine failure. During simple engine failures (the accessory gearbox not seized), the tailrotor WILL NOT stop rotating because of the design of the freewheeling unit and accessory gearbox. The 25 knots is recommended run on landing speed on a prepared, flat surface. It's possible to autorotate to a landing with minimal or even zero forward speed.

The speeds and location of components will vary with different aircraft models.

All times are GMT Page 1 of 1

Related Questions