hello to all-

I've owned my first Beech Craft since February of this year (2011), a nicely equipped 1987 F33A, based out of KISP. Have a total of just about 50 hours in the Bonanza and love the plane. It was a big step up from my Archer II, (another really nice forgiving aircraft, but just too slow).

on Saturday 08/13/11 i flew from isp to bhb at 5000 then climb to 7000 and noted my airspeed (indicated) never really got out of the 140-147 kias range. hot day, and high da. (bhb which is at 83' msl, was calling a da of 1300' msl.) i unfortunately did not record and do not recall temp at altitudes. groundspeeds were in the 150 - 157 range at times . my concern was w/ the indicated airspeed. usually i can easily cruise at 160 kias, a few knots above the diamond on the asi. is the decrease in Indicated airspeed just a function of the atmospheric conditions i.e, low molecular density, etc.. same thing coming back at 6000. low IAS.

i was only person in plane, lightly loaded, 23" @2500 leaned at 13 gph, egts were 1400-1490, all cht's and oil temp/press wnl. any help would be appreciated.

Thanks-

Bruce

The first thing to check is the ASI/pitot system accuracy: Do a 3 or 4 leg pattern at cruise speed, using the "GPS PEC" method. You can find instructions with Google search.

If the ASI is reading low, it could be either a defective ASI or a pitot system leak.

I'm attaching a worksheet.

thank you paul

The easiest way to check for a pitot-static leak affecting the airspeed indicator:

In flight open the pilot side window slightly as you look at the indicator. If the needle jumps up a few knots there is a leak. Most common leak source is at a Tee or 90° fitting and inspection of those would be my starting point beginning at the back of the instrument.

In the photo my mechanic is removing the AI for access to the pitot tubing and fittings so he can fix my leak. He found a cracked fitting by carefully examining the fittings with an inspection mirror.

thanks max... i knew by joining and posting i'd get some thoughtful suggestions.