Small quiz!

[Guest dape]

A blocked or frozen pitot and/or static system will affect TAT and SAT readings. No way to get a precise altitude by using temperature. What about not using any of your own systems but another aircraft flying at same altitude. Just ask that guy.TCAS wont work either as transponder altitude reporting is incorrect.David P.

[marcom 139]

"A blocked or frozen pitot and/or static system will affect TAT and SAT readings."I must admit I don't know where the temperature probes are! If they are directly at the pitot/static ports, then yes, you are probably right. As this is not part of the training curriculum, I really don't know what the TAT/SAT was at the time! (Shame on me)"No way to get a precise altitude by using temperature."Agree with that."What about not using any of your own systems but another aircraft flying at same altitude. Just ask that guy."Yeah, that would work, but only in VMC!"TCAS wont work either as transponder altitude reporting is incorrect."Agreed!Mark

[Guest tmetzinger]

>Recently I read an accident report for a 757 in South America>that crashed into the sea, that suffered a similar set of>problems.>The cause was determined to have been the static ports were>taped over during maintenance work, and nobody remembered to>take the tape off.>>True, but the real cause was the absolutely horrible preflight inspection.

[Guest tmetzinger]

>G'day >For altitude i think you should be able to access the ALT info>from the GPS system via the FMC as position data.>All IFR approved GPS's have true ALT data available via a>position page.>Don't know the other one though.>Have funAlthough the GPS altitude (without WAAS) is not always very accurate.

[emwardjr 0]

Regards,Ed

[Guest Goose]

Break the glass on the VSI. The VSI will read in reverse ie; when climbing it will show descending. Take feet per minute on VSI and you can roughly calculate your altitude.

[marcom 139]

Wow quite a few replies to the questions!!There were a lot of great ideas posted, and I guess many of them would work, even though pilots are just showed a handfull of options.While not extremely precise, they allow situational awareness at a quick glance without a lot of math (not a good idea in a high stress situation).Here are the 'solutions' I know:a) During takeoff roll, or whenever, the airspeed indicator would first freeze and then function as an altimeter (ie the airspeed would increase as you climbed out). Naturally, your altimeter would freeze aswell.:( Three of the most instruments would be gone, namely: airspeed indicator, altimeter and vertical speed. The vertical speed indicator will fluctuate as the IRS's are still supplying acceleration information which in fact is correct. But don't rely on the VSI!Same applies for the airspeed trend vector.Other systems affected would be:overspeed warningTAS indication on NDWind incation on NDTransponder mode C and S as the altitude encoder is using wrong data.And every other system requiring airspeed/altitude information.c) PF continues to fly the aircraft, observing PLI if shown (this uses AoA (angle of attack) to indicate a stall) and flying a normal G/A profile if failure happened during takeoff. PNF grabs the QRH (quick reference handbook) and checks the required pitch/N1 setting for the current weight and phase of flight which is then maintained.If the wind was not strong (IE no big difference between TAS and GS), and the aircraft is not high, GS can be used as a reference, but should not be used as a goal instrument.Inform ATC! This is extremely important, as ATC will see your failed altitude information and they have to make sure no one gets into your way. If your altitude is unconfirmed, they will clear traffic away from you at every level.Airspeed can not be directly determined. You'll just fly the pitch/thrust settings written in the QRH and hope that there is no big typing mistake :-)Vertical speed is completely unavailable. Again, use the pitch/thrust settings.and for the altitude information:d) One way of determining altitude was already answered: all GPS equipped aircraft can tell you your true altitude if there is satellite coverage.The other way uses a small trick: Activate the weather radar, set a negative tilt (unfortunately, I forgot what degree it was, but I'll check the QRH and write it down) and the echo returns you see on the ND is where the beams hit the ground. Divide the distance by ten and you have your altitude above ground times 100 ft. (If the beams return at 80 nm you are at 8000 ft).I really like this trick and is extremely useful if your failure occurs near the Alps! Of course it assumes that the terrain below you is just as high as the terrain 80 (or wherever) ahead of you, but it will show you if the terrain is rising or not)Well that's all :-)Regards,Mark

[Guest ilh]

I don't believe that works in a pressurized cabin. Besides, in something like a C-172, breaking the VSI face should give you an alternate static source, and your ASI and Altimeter should start working. Your VSI is toast though.Lee Hetherington (KBED)http://www.precisionmanuals.com/images/betaimg.jpg

[Guest ilh]

Fortunately, there aren't any volcanoes within 3000 miles of KJFK.Lee Hetherington (KBED)http://www.precisionmanuals.com/images/betaimg.jpg

[Guest HepburnUGA]

Hey Mark,Is that the crash that a compressor blade or something managed to cut all three hydraulic lines, and the pilot managed to fly the plane using differential power settings?Pretty amazing airmanship even though it ended in tragedy.Jeff

[Guest Goose]

"VSI will work" but in reverse. Sorry I was not thinking of the 737 when answering the question.My thoughts were with GA aircraft.

[marcom 139]

Okay I just checked again and here is the procedure again (using weather radar for altitude checks)Set tilt to -6.5

[chumley 0]

>Fortunately, there aren't any volcanoes within 3000 miles of>KJFK.>>Lee Hetherington (KBED)>http://www.precisionmanuals.com/images/betaimg.jpgR U sure?My girlfriend erupted like one when I came home a little worse for wear with a smile on my face and the smell of another woman on my clothes.Andy b

[Guest eker]

Hi MarkRegarding APU as altimeter during climb....APU bleed not avail above 17000` :-) ;-)eker