All things being equal, how do you figure out what an aircraft's altitude should be when it's making a short hop - for example, Allentown (Lehigh Valley INTL) to Atlantic City with, say, a Learjet?Also, how do you figure out what your minimum glide-to-safety (when possible) altitude should be - for example, crossing between islands?Thanks,Andrew

I use FSNavigator, and you can plug in the aircraft climb speed and rate, and it will calculate how high you can go using those variables.

Hi...Concerning glide distances. This is published in the POH for each aircraft via glide performance charts.If memory serves me correct, most single-engine aircraft get somewhere around 1-3nm glide distance per 1000ft of altitude lost when configured for best glide (flaps and gear up, at best glide speed usually close to Vy). Commercial jets can usually glide much better (depending on weight).For a conservative general approach to this, use 2nm per 1000ft. If you're crossing a water passage with a maximum 15nm mid-span distance, for example, you should use 7500ft minimum to get you back to land + 1000ft for making the 180deg turn if required (even more if you want to be extra safe). With that, a 30nm crossing, with a 15nm mid-span = minimum 8500ft safe at the mid-point. This doesn't account for wind though, so add some extra altitude on top of that just in case.One time early in my piloting experience, while renting a plane from Port Angeles, Washington (C172), I experienced carb icing on descent (pilot error, did not apply carb heat as recommended per my rpm settings). This was from Orcas Island back to Port Angeles (about a 15mile crossing). My passengers wanted a close-up of a lighthouse so I came in fast and steep and made a pass. Airspeed slowing, 500ft off the deck I started to bring in the power and the engine did nothing but cough and shake violently. After 3 seconds of wasted time (OMG I can't believe this is happening), I finally started my emergency procedures, set best glide speed and turned for approach over a VERY ROCKY beach. Didn't have enough altitude or airspeed to make anything other than the coast. I was going to ditch it next to the shore. Two big mistakes. Not maintaining safe altitude and failure to use carb heat. Luckily as soon as I hit the carb heat (a couple seconds layer) the engine came back to life, and we made a non-eventful landing. The point of that story: Planning and actually flying safe altitudes, always being prepared for an engine failure, and always looking for (and staying in range of) possible forced landing zones are critical to the safety of your flight. Don't ever leave yourself without options. It doesn't hurt to follow proper aircraft operating procedures either (carb heat!) ;)

Thanks guys

I've flown over that same stretch between Port Angeles and Cattle Point on San Juan Island. I also chose 8,500' as a safe minimum altitude for an over water crossing. I actually went north over Port Townsend and wanted to stay above the Chinook B MOA. Upon my return I passed just to the west end of the Chinook B MOA and east of Port Angeles.The Cessnas have a glide of 8:1. Since we're talking feet that would be 11,500' of altitude to glide a Cessna safely for 15 nautical miles.If your intention is to fly safely over water, then give yourself a buffer altitude to glide either direction when at midspan of your water crossing.:)