On paper ...when you start to read this it may come across rather fussy or complicated.
But - in practice the Loss of the TR Drive is fairly final it's going to require a bloody swift reaction, to be able to engine off from the hover in order to have a chance of being in a attitude to achieve a decent cushioned landing. In forward flight - well if you manage to contain the yaw you might be able to postion (using low power or suitable PWR/IAS combo) the helo to a safe area for an EOL or you'll just have to enter auto, shutdown the engines and accept an interest EOL at the bottom. All very challenging and something I would rather not try unless I was in a sim.....that said if I was on the NOTAR I suppose I wouldn't have the problem ....probably something else to think about though ....I'm sure.
Now - If you have a Tail Rotor control failure
There's quite alot you can achieve. If you take your time:
1. Define the problem - is it AFCS, Hydraulics, a jam, cable snap or somebody's bag rat wedged behind the pedal. It could be as simple as that - somebody's FOD.
2. Check fuel - if you've got loads we can take all the time in the world to get it right, if not then you'll have to do the same assessments but with a sensible level of alacrity.
3. You need to consider what configuration the jam or failure has left for you to deal with. Is it either:
1. low power controlled flight (pedal Positon)
or
2. High Powered controlled flight (pedal pos'n)
I make this broad assessment criteria based on the position of the applied pedal at the time of the problem first coming to light.
The pedal applied will vary as to type and MR blade rotation.
First of all you need to do a handling check:
which should take the following form:
1. Maintain Wings level
2. Fly at Min power speed (usually 60-70kts)
3. Using collective apply a power setting that will bring the 'ball' in to the centre.
Don't concern yourself with collective and power settings too much.
Then check you RCDI and note the following
A. LOW POWER pedal situation -
for example: you find you have Wings level, Ball in middle and a ROD of 1000'/ min
This means that you could return to a large grass field in a skidded helo or a large runway in wheeled helo and carry out a pre-briefed auto or low powered descent to the ground touchng down at up to approx 60 knots and smoothly shutting down the engine(s) as you enjoy the rutted camel ride from hell across the airfield or you can differentially break if you have them fitted - Luxury. Now a 60kt touch down is very saucy but, in many aircraft a, doable get out of jail type manoeuvre. Obviously - a high wind day of 30 knots straight down your landing area is going to help immensely.
This is good news - you can now decide whether you want to do another handling check to see if you can still maintain your Wings level ball in middle at a slower speed and lower rate of descent. Who knows .....but if you have the fuel keep trying.
B. HIGH POWER PEDAL situation -
Lets do the handling check again -
WINGS LEVEL and put the BALL IN THE CENTRE with collective and find out where the power ends up. Lets say it provides the worse case scenario of a power higher than that required to hover.
We already know that the if we bring the IAS back towards a very low IAS that the PWR REQ'D will increase. As we decel we continue to try to maintain - WINGS LEVEL,BALL IN MIDDLE now by pulling collective to maintian our condition.
We see that we are climbing slowly - so what can we vary ?
1. Weight - it's reducing as we burn fuel ..so it ain't helping us
2. Even less IAS almost or even hovering .....but once we reach this we're at a point where the power req'd is now a MAX value.....but we are still climbing slowly.
3. Nr - if we vary Nr by way of a carefully controlled brief to co-pilot or crew member or self brief by the single pilot we can retard the throttle or SSL's to start a controlled reduction of Nr thus reducing Total Rotor Thrust - but maintaining useful power on Nr values. You should practice this before attemting the approach. If the Nr should decay too much too early use lever t regain Nr until you have had time to apply a little more throttle. Try to aim for a ROD around 200-300'/min
Your approach config should be practiced at altitude above your intended LS and your approach planned so that you start on an extraordinary long final (terrain dependant of course)to achieve a short final by approx 300 - 500' where you are continuing to reduce speed progressively and controlling your reduced Nr to give you a ROD around 200-300'per min at this stage on the approach the aircraft will not be pointing straight or wings level until you reach your IAS you assessed earlier. However, as you approach the hover you will have ground effect to contend with and will have to further reduce the Nr (retarding throttles and SSL's even further. As you approach the Hover or low speed you should aim to be satisfied with your heading, attitude and sink rate ...if so then smoothly retard the levers/lever or twist off the remaining power nice'n'gently and the helo will descend through the GE and you can .....shutdown and go back to the bar for several beers.
During both of these procedures you can always throw it away if you need to...... accepting the awkward manner of flight that you will achieve (out of balance wing low etc) Climb up, line yourself up again and practice it all over again - provided you haven't had to do the Engine OFf bit that is.
I have taught these techniques as have many other instructors - I'm sure, but the problems above are worth practising. If you've ever had a birdstrike that was big and it came through the perspex and wrapped it's wings and colon around your pedals ...you will want to have tried this at some point.
One important point tho' is don't get too wrapped up inside the cockpit it is possible to fly reasonably normally during the preparation and positioning. But at the end if it looks right outside the cockpit, the chances are everything will be alright so keep looking out and flying the beast.!!!
Sorry if it's long winded or if it's stuff you already know......I'm probably the only mug trying to attempt to paint the picture on paper..... back to my Guiness byeeee
[This message has been edited by eden (edited 13 February 2001).]
[This message has been edited by eden (edited 13 February 2001).]