Takeoff distance question

[oilcanbland]

For all of you who have the Jeppesen Instrument/Commercial Manual (the big thick grey textbook), I have a question about a performance problem that our teacher gave to us. It is using the Takeoff Distance chart on page 12-68. Here are the conditions if anyone feels like helping me out to see if I'm right.

Weight: 4100 lbs
Pressure Alt.: 5800 ft
Temp.: 18 C
Level, dry grass, runway
12 kts headwing component

Here are the figures that I came up with.

1896 ft for the ground roll
2910 ft to clear a 50 ft obstacle

If anyone wants to figure it up to see if I'm right, I'd appreciate it. Just curious to see if I'm right. Thanks a lot.

 

[groundpointsix]

I agree with your answer for ground roll, but twice i've come up with 2,884 feet for obstacle clearance. Try doing the exact same sequence of calculations with the obstacle clearance numbers as you did with the ground roll and see what you come up with. (If your teacher marks it wrong, just tell him you added a safety factor)