measuring airstrip lengths
Posted: Wed Jun 02, 2004 3:44 am
An old Alaska pilot I know told me about a good way to measure out the length of that uncharted airstrip or sandy stretch of beach that you're thinking about landing on. It's an old trick,but some of you might not have heard of it.
At 60 knots (70 mph) groundspeed, you cover 100 feet every second. Just slow down to a steady 60 knots,time your flight along the strip,and do the math. If you're on the way somewhere & see an inviting place but don't want to take the time to slow down & stabilize at 60 knots, use 90 knots (105 mph) instead. That works out to 150 feet per second. Takes some of the guesswork out of the land/no-land decision. A GPS comes in handy to check the indicated airspeed for a given groundspeed.
I remembered hearing about this trick when I was given a digital stop-watch like alot of guys use for IFR. I couldn't remember the speeds involved but it was easy to work the math out. I've tried it out,and it works pretty slick. Gives me a good reason to pack the stopwatch around anyway.
Eric
At 60 knots (70 mph) groundspeed, you cover 100 feet every second. Just slow down to a steady 60 knots,time your flight along the strip,and do the math. If you're on the way somewhere & see an inviting place but don't want to take the time to slow down & stabilize at 60 knots, use 90 knots (105 mph) instead. That works out to 150 feet per second. Takes some of the guesswork out of the land/no-land decision. A GPS comes in handy to check the indicated airspeed for a given groundspeed.
I remembered hearing about this trick when I was given a digital stop-watch like alot of guys use for IFR. I couldn't remember the speeds involved but it was easy to work the math out. I've tried it out,and it works pretty slick. Gives me a good reason to pack the stopwatch around anyway.
Eric