cody12

Rejected Take Off : Stop or Go ?

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In a single engine aircraft on takeoff, the stop/go decision is much simpler when the engine fails completely.  :rolleyes:

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1 hour ago, Mooneymite said:

In a single engine aircraft on takeoff, the stop/go decision is much simpler when the engine fails completely.  :rolleyes:

and with 2 miles of runway!

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There is a thread around here that included video from witnesses on bicycles...

 

To apply this to Mooney flying...  a rental Mooney crashed this past year after landing long and then decided to go around late...

Crashed in the trees off the end of the runway.  This was on the second attempt at landing.

 

Don't turn a long landing into a funeral. Go around prior to landing long...

 

Best regards,

-a-

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And here I always thought that a "rejected takeoff" was by definition one where you didn't take off . . . Otherwise it would just be a takeoff, albeit maybe a "bad takeoff" or a "long takeoff."

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As far as I know we don't have data to help us make a decision, but that won't stop me from posting my opinion!

1.  I'd rather go off the end of the runway at 20 knots trying to stop then go off at 50 knots trying to fly.

2.  I never liked the use of V1 that the airlines use. I always preferred what we used in fighters in the Air Force.  V1 only tells you the speed at which it will take the same distance to stop as it does to continue.  It also tells you that you can stop at speeds before V1 and get airborne after V1 without running out of runway.  However, other than that, it does not care how long the runway is.  Under identical performance conditions, V1 is the same on that 5000' runway at MDW as it is on the 12,000' runway at DTW.

In the AF we had 4 numbers:

a.  Decision Speed.  That's the minimum speed you had to reach before you could lose an engine and get airborne before you ran out of runway.

b.  Critical Engine Failure Speed.  Essentially the same as V1.

c.  Refusal Speed.  The maximum speed you could reach before engine failure, take 2 seconds to make the decision, and then stop on the available runway.

d.  Adjusted Refusal Speed.  The same as above, but stop with 1000' of runway remaining.

Below Decision Speed, you had no choice, you had to stop.  Above Refusal Speed, you had to go.  In between you could do either one.  Given enough runway, Refusal Speed could be the same as liftoff speed.

What really helped was we had a Min Accel Check Speed.  That was the minimum speed you needed to see after a 1000' roll to ensure you were getting expected performance.  Might be useful in a Mooney, but by the time we roll a 1000', we might be airborne already.

I suppose if you really cared, you could add the POH takeoff roll and landing roll together.  If they add up to less than runway length, you could abort right up to liftoff.

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7 hours ago, carusoam said:

There is a thread around here that included video from witnesses on bicycles...

 

To apply this to Mooney flying...  a rental Mooney crashed this past year after landing long and then decided to go around late...

Crashed in the trees off the end of the runway.  This was on the second attempt at landing.

 

Don't turn a long landing into a funeral. Go around prior to landing long...

 

Best regards,

-a-

And Anthony didn't we see that superior decision making by one Ovation owner recently ;) 

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Hence the reminder...  Landing long isn't a good option.  Too fast has already happened while chewing up remaining runway at an alarming rate.

Two seconds is what you use when you already know the answer. Problem is when this happens we aren't even sure of the question... the two second rule for automobiles on the highway=100 yds..?

Stuff we probably learned early on.  Then got forgotten along the way...?

Half the runway length is often used because the halfway point is often the easiest point to identify while this brain straining activity is going on... in this case you should be flying or stopping, not deciding....

 

Having O3 power could be a lifesaver......hmmmm!

Best regards,

-a-

 

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Try taking off and then cutting power at 25' height then landing and stopping. It takes a lot more runway than you think. 

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