PPRuNe Forums - View Single Post - High accident rates in light twins an alternative?
Old 28th May 2008, 20:33
  #23 (permalink)  
Pace
 
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Wizofox

>One big difference between Skydivers (1200 jumps and an AFF rating, just by the way!!) and aeroplanes is that skydivers don't have engines!! Aeroplanes don't have "Terminal velocities <

Firstly aeroplanes most certainly DO have terminal velocities!!! and sky divers most certainly DO have engines :-) Ok not in the conventional sense but in the Kinetic energy they are using returning earthbound and which was created hoisting them skybound. In the same sense a glider has an engine in its Kinetic energy which was created pulling it skybound and which is on tap to the glider pilot through the joystick earthbound. the joystick is his throttle if you like.

No again :-) Put in simple terms as I am a practical sort of pilot and not a mathematician what do you do if you are holding blue line, you are at 400 to 500 feet and rather than getting a climb your VSI and altitude are going down?

You either panic as do many low time twin pilots and pull back trying to get a climb and go into coffin corner or you put it down hoping you dont take out trees or buildings in the process.

Take my word for it there are many situations as above where the aircraft ends up as a hole in the ground. Hence the bad engine out record of twins.

You also know that while many twins really struggle especially on hot days at grosse weight and blue line does not work in giving you the desired climb or even maintaining altitude.

So you have two choices you either continue trying to get a climb and end up in coffin corner with the usual stall /spin hole in the ground or you close both engines use the kenetic energy( which incidentely was created by the aircraft engines dragging the plane mass to altitude) and become a glider to a forced landing. (using the inherant kinetic energy to control your speed on the way down ie your spare engine as with the Skydiver) :-)

Your other option is to try out what I have said on your next flight. Mathematics or armchair pilot discussions aside it does work. I have seen and experienced the reality of this with my own eyes.

Then when you have tried it come back and explain why.
As they say the proof of the pudding is in the eating

You are missing something in the science or the mathematics here but the clue has to be in the fact that light twins will happily cruise all day on one engine at 127 kts but will not happily climb at blue line in all conditions and that is a practical answer.

Pace

Last edited by Pace; 28th May 2008 at 21:09.
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