Now that you’re all leaning efficiently I’d like to remind you of other means of saving money. On my last trip down toSW France I surged along at up to 210kts saving about 20 minutes fuel. Firstly I had climbed to 9500ft, thereby gaining about 2% True Airspeed (TAS) for every 1000ft altitude, so that although the Indicated Airspeed was 150kts theTAS was 170 kts.Where did the rest of the economy come from – the tail wind. At 200ft it was a measly 10kts, at 5000ft 20kts was on offer but the 10,000ft wind was a stonking 35kts.
Now I’m not suggesting FL090 for your run down to coffee at Compton Abbas (to be fuel and speed efficient the time in the climb should not exceed about 20% of journey time) but as long as you keep out of Class A airspace, using higher levels and tail winds will save you money. Incidentally, in the average light aircraft, should the engine fail you will have gained about a minute and a half descent time per thousand feet.
Geoff Prout, CFI