pitot static errors checklist.

[compressor stall]

After a personal minor run of pitot static errors and subsequent investigation of previous accidents caused by such errors (e.g. the US 727 with pitot icing, the 737 off the Domenican Republic, the one in Peru etc.) I am trying to compile a list that will cover all the possible errors involved with the pitot static system.

The format I think would work would list the symptom of the primary instrument, secondary effects and thirdly a remedy if possible.

Could PPRuners add to the list the ones they have themselves personally experienced. After a raft of these, we can collate them and print it out to lie around the back of the flight bag for reference on a dark and stormy night.

I will begin with one I had the other very very very dark night.


Aircraft
B200

SYMPTOM
Pilot's AirSpeed indicator reducing rapidly about 5 seconds after takeoff.

SECONDARY EFFECTS
Nil

CAUSE
Leaking face on the AirSpeed Indicator

Remedy
1. Push very gently on the ASI to try and seal it
or
2. Depressurise the cabin.

[OzExpat]

I don't know if this one will be any help but, back around 1984, I experienced the following on a flight from Port Moresby to Kiunga.

Aircraft
PA23

SYMPTOM
Zero airspeed noted during take-off run.

SECONDARY EFFECTS
Nil

CAUSE
Blocked pitot tube.

Remedy
Landed at Kiunga and quietly removed the leather pitot cover. :}

[A/P Disc]

It was a 757 in the Dominican Republic not a 737.
I think that in the same year there was a 757 in Peru which
took off after a paint job with all the ports still covered up.
It crashed into the ocean. Not a very nice story.

[compressor stall]

OzEx...

There are those who have and those who will. Remember chasing after a PA34 at EML as he taxied away for night circuits with the pitot cover still on. Wobbled the elevator to get their attention, and removed it for them.

AP Disc

thanks for the correction. Too right - not a very nice story. But I wonder had they read a thread like this, or had a checklist of the possible errors could tragedy have been averted?

Keep em coming!

[slingsby]

Not listed, can't find reference to it but a colleague in a B767 had a night stop in BNE, same aircraft, prepared for departure, taxied to active, all normal indications, ready for normal flight back to base.
V1 - 139knt Vr 148knt rest I don't remember.
PF L/s sets power/EPR, PNF calls airspeed active, and thats his last call, Capt notices ground speed very fast but no 100knt call and judges his speed close to V1, looks down at his ASI (134knts) and a quick glance at his FO's ASI , and calls immediate stop as it's only reading 80knts. High speed abandon, flat spots 2 tyres, turns off the runway and stops.

Turns out, overnight a large insect had nested in one of the pitot heads and subsequently blocked it. Engineers had not placed any covers on the tubes or holes, QA audit actioned.

[OzExpat]

True enuf Stallie, but the flight time in the old Aztruck was a shade over 2.5 hours...

[Shore Guy]

From the latest Boeing Aero Magazine:

http://boeing.com/commercial/aeromagazine/aero_23/EFII.html

[BEagle]

Whilst in rapid rate of climb, I noticed the ASI decreasing and altimeter beginning to freeze. Normal level flight attitude and cruise power settings were selected and the ac flown at normal AoA. ASI and altimeter continued to give faulty indications.


This was in a F4. I called my leader and suggested dumping fuel and recovering in formation. However, being a press-on-itis flight commander, he wanted the exercise completed first...... Eventually we recovered in close formation - but he insisted on staying in cloud even though we could see the ground quite clearly through large holes and knew where we were. We flew the GCA, then the fool said that we'd overshoot into a visual circuit 'for practice'. I'd had about 20 minutes in close formation at this stage and was pretty pi$$ed off - but even more so when he declared his intention to overshoot from the visual circuit for another! The instruments still weren't working properly and the altimeter was hunting in synchronisation with the normal cabin pressure surges, although it seemed to settle when I pulled the vent knob. At this stage my navigator said to him "This is just practice bleeding - we've got actual instrument failure, so let's stop dicking around!" So we landed; in the debrief we told him what we thought about his poor leadership in delaying a safe recovery......

It turned out that a static pipe to the navigator's altimeter had become disconnected and cockpit air pressure was getting into the static system as a result!

The navigator left the RAF a few years later to become a senior bod in an organisation providing military support flying, I was posted to the VC10 about a year later......but, of course, the flight commander was promoted.

[Shore Guy]

And from an older Boeing Aero issue....


http://www.boeing.com/commercial/aeromagazine/aero_08/erroneous.html