|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : toa|
|Altitude||agl bound lower : 0|
agl bound upper : 0
|Controlling Facilities||tower : bos|
|Operator||general aviation : personal|
|Make Model Name||Small Aircraft, Low Wing, 1 Eng, Retractable Gear|
|Qualification||other other : other|
|Function||flight crew : single pilot|
|Qualification||pilot : private|
|Anomaly||aircraft equipment problem : critical|
non adherence : far
|Independent Detector||aircraft equipment other aircraft equipment : unspecified|
|Resolutory Action||none taken : detected after the fact|
|Consequence||faa : investigated|
|Air Traffic Incident||Pilot Deviation|
The airplane involved was an small aircraft brought to our shop by the owner for installation of altitude encoder, including the mandatory static leak test and altitude encoder calibration test. The installation of the encoder was routine. The problem developed with the static check and calibration test. To perform this test, we would normally use a pitot/static box, the pilot opening would be sealed by an aluminum sleeve that is part of this test equipment. The static ports would be sealed with tape. We would then tap into the static system and apply vacuum using this test box. Upon completion of the test and removal of our tap-in, the aluminum sleeve is removed next which is also our reminder to remove the tape from the static ports. The aluminum sleeve is large enough and noticeable enough that its absence cannot be overlooked when folding up the pitot/static box, thus it is a good reminder to remove tape from the static port. The pitot tube on this model small aircraft is a nonstandard shape, instead of a tube protruding forward, it is a blade sticking down from the bottom of the wing. There is no way to use the aluminum sleeve on this nonstandard shape. To perform this test, we taped around the pitot static blade, sealing both pitot and static ports. The actual test and calibration were done using the pitot static box. Upon completion of the test, I removed my tap-in, folded up the hoses, checked the box to make sure there were no missing pieces of equipment, and removed the box from the aircraft, the test was complete. I then told my boss I was finished with the airplane and said that it was ready for him to look at. The boss then assigned me to work on another aircraft. Unfortunately, neither the boss nor I detected the tape still firmly secured to the pitot static blade, rendering all pitot static instruments inoperative. The aircraft was returned to the owner in this condition. The negative possibilities, including fatalities, which could have resulted from this problem are obvious. We were extremely fortunate. There are several factors that contributed to this problem. First, the nonstandard pitot static blade prevented use of the aluminum sleeve, which in return was my reminder to check for tape remove from static ports. Second, our procedure to xchk each other upon completion of work evolved thru years of experience and lacked the formalities of a written procedure or checklist. While the boss and I have end-of-job cleanup procedures, each procedure was designed around a standard situation and did not work as well in a nonstandard situation. Corrective action: 1) remove before flight' banners to be attached to pitot tube and static ports, and to be removed per end-of-job checklist by the technician. 2) flourescent orange 'unsafe, do not fly' placard to be attached to the tachometer and to be removed only by the inspector per end-of-job xchk procedure. 3) written end-of-job checklist for technician. 4) written end-of-job xchk procedures for inspector. 5) no log book sign off without used 'unsafe, do not fly' placard affixed to office paperwork. Callback conversation with reporter revealed the following: reporter confirmed that procedure have been changed to insure this type of incident does not happen again. FAA did examine the incident but no action was taken against the company or the reporter. Apparently the owner failed to note the tape on his walk-around and took off with the pitot system inoperative. Minor damage was done to the aircraft on the landing.
Original NASA ASRS Text
Title: MECHANIC FAILED TO REMOVE PITOT AND STATIC COVERS AFTER MAINTENANCE HAD BEEN PERFORMED ON THE ACFT.
Narrative: THE AIRPLANE INVOLVED WAS AN SMA BROUGHT TO OUR SHOP BY THE OWNER FOR INSTALLATION OF ALT ENCODER, INCLUDING THE MANDATORY STATIC LEAK TEST AND ALT ENCODER CALIBRATION TEST. THE INSTALLATION OF THE ENCODER WAS ROUTINE. THE PROBLEM DEVELOPED WITH THE STATIC CHECK AND CALIBRATION TEST. TO PERFORM THIS TEST, WE WOULD NORMALLY USE A PITOT/STATIC BOX, THE PLT OPENING WOULD BE SEALED BY AN ALUMINUM SLEEVE THAT IS PART OF THIS TEST EQUIPMENT. THE STATIC PORTS WOULD BE SEALED WITH TAPE. WE WOULD THEN TAP INTO THE STATIC SYSTEM AND APPLY VACUUM USING THIS TEST BOX. UPON COMPLETION OF THE TEST AND REMOVAL OF OUR TAP-IN, THE ALUMINUM SLEEVE IS REMOVED NEXT WHICH IS ALSO OUR REMINDER TO REMOVE THE TAPE FROM THE STATIC PORTS. THE ALUMINUM SLEEVE IS LARGE ENOUGH AND NOTICEABLE ENOUGH THAT ITS ABSENCE CANNOT BE OVERLOOKED WHEN FOLDING UP THE PITOT/STATIC BOX, THUS IT IS A GOOD REMINDER TO REMOVE TAPE FROM THE STATIC PORT. THE PITOT TUBE ON THIS MODEL SMA IS A NONSTANDARD SHAPE, INSTEAD OF A TUBE PROTRUDING FORWARD, IT IS A BLADE STICKING DOWN FROM THE BOTTOM OF THE WING. THERE IS NO WAY TO USE THE ALUMINUM SLEEVE ON THIS NONSTANDARD SHAPE. TO PERFORM THIS TEST, WE TAPED AROUND THE PITOT STATIC BLADE, SEALING BOTH PITOT AND STATIC PORTS. THE ACTUAL TEST AND CALIBRATION WERE DONE USING THE PITOT STATIC BOX. UPON COMPLETION OF THE TEST, I REMOVED MY TAP-IN, FOLDED UP THE HOSES, CHECKED THE BOX TO MAKE SURE THERE WERE NO MISSING PIECES OF EQUIPMENT, AND REMOVED THE BOX FROM THE ACFT, THE TEST WAS COMPLETE. I THEN TOLD MY BOSS I WAS FINISHED WITH THE AIRPLANE AND SAID THAT IT WAS READY FOR HIM TO LOOK AT. THE BOSS THEN ASSIGNED ME TO WORK ON ANOTHER ACFT. UNFORTUNATELY, NEITHER THE BOSS NOR I DETECTED THE TAPE STILL FIRMLY SECURED TO THE PITOT STATIC BLADE, RENDERING ALL PITOT STATIC INSTRUMENTS INOP. THE ACFT WAS RETURNED TO THE OWNER IN THIS CONDITION. THE NEGATIVE POSSIBILITIES, INCLUDING FATALITIES, WHICH COULD HAVE RESULTED FROM THIS PROBLEM ARE OBVIOUS. WE WERE EXTREMELY FORTUNATE. THERE ARE SEVERAL FACTORS THAT CONTRIBUTED TO THIS PROBLEM. FIRST, THE NONSTANDARD PITOT STATIC BLADE PREVENTED USE OF THE ALUMINUM SLEEVE, WHICH IN RETURN WAS MY REMINDER TO CHECK FOR TAPE REMOVE FROM STATIC PORTS. SECOND, OUR PROCEDURE TO XCHK EACH OTHER UPON COMPLETION OF WORK EVOLVED THRU YEARS OF EXPERIENCE AND LACKED THE FORMALITIES OF A WRITTEN PROCEDURE OR CHECKLIST. WHILE THE BOSS AND I HAVE END-OF-JOB CLEANUP PROCEDURES, EACH PROCEDURE WAS DESIGNED AROUND A STANDARD SITUATION AND DID NOT WORK AS WELL IN A NONSTANDARD SITUATION. CORRECTIVE ACTION: 1) REMOVE BEFORE FLT' BANNERS TO BE ATTACHED TO PITOT TUBE AND STATIC PORTS, AND TO BE REMOVED PER END-OF-JOB CHECKLIST BY THE TECHNICIAN. 2) FLOURESCENT ORANGE 'UNSAFE, DO NOT FLY' PLACARD TO BE ATTACHED TO THE TACHOMETER AND TO BE REMOVED ONLY BY THE INSPECTOR PER END-OF-JOB XCHK PROCEDURE. 3) WRITTEN END-OF-JOB CHECKLIST FOR TECHNICIAN. 4) WRITTEN END-OF-JOB XCHK PROCEDURES FOR INSPECTOR. 5) NO LOG BOOK SIGN OFF WITHOUT USED 'UNSAFE, DO NOT FLY' PLACARD AFFIXED TO OFFICE PAPERWORK. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: REPORTER CONFIRMED THAT PROC HAVE BEEN CHANGED TO INSURE THIS TYPE OF INCIDENT DOES NOT HAPPEN AGAIN. FAA DID EXAMINE THE INCIDENT BUT NO ACTION WAS TAKEN AGAINST THE COMPANY OR THE REPORTER. APPARENTLY THE OWNER FAILED TO NOTE THE TAPE ON HIS WALK-AROUND AND TOOK OFF WITH THE PITOT SYSTEM INOP. MINOR DAMAGE WAS DONE TO THE ACFT ON THE LNDG.
Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.