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Altitude deviation altitude excursion - pilot ends up 1000 ft higher than clearance and is unable to explain how it happened.
| Attributes | |
| ACN | 300166 |
| Time | |
| Date | 199503 |
| Day | Sat |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : leb |
| State Reference | NH |
| Altitude | msl bound lower : 10000 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : mht |
| Operator | general aviation : personal |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise other |
| Route In Use | enroute airway : v-496 |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : single pilot |
| Qualification | pilot : cfi pilot : commercial pilot : instrument |
| Experience | flight time last 90 days : 70 flight time total : 1200 flight time type : 14 |
| ASRS Report | 300166 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Qualification | controller : radar |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance |
| Independent Detector | other controllera |
| Resolutory Action | flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
I was flying the return leg of a round trip to (aug) from (5b2). The leg to aug was flown at 11000 ft. Was on ground at aug for about 1 hour. The return flight plan was: aug, v- 39, neets, V-496, gfl, direct 5b2, cruising altitude 8000 ft. After climbing to 8000 ft, asked portland approach for higher because 8000 ft put me in and out of cloud tops. At XA00 hours local manchester approach asked me my altitude. Since I was flying wbound, I assumed that I was at 10000 ft. Autoplt altitude hold was engaged and the 100 ft of the altimeter was straight up. Mht said they showed me at 11000 ft. Why was I at 11000 ft and how and when did I get there?? Possible answers: -- when I asked portland approach for higher, I asked and received 10000 ft but climbed to 11000 ft ( I had just flown out to aug at 11000 ft). I then cruised level at 11000 ft for 3 mins before ATC realized I was 1000 ft off the assigned altitude. -- I asked for and was given 11000 ft, but ATC put 10000 ft on my flight strip since that is a normal wbound altitude. -- I asked for and was given 10000 ft, climbed to 10000 ft, set altitude hold on autoplt when at 10000 ft. Then the autoplt disengaged while in a slight trim up condition, resulting in a very slow climb to 11000 ft. As plane neared 11000 ft, I noticed the autoplt was disengaged, so without carefully checking altimeter, I re- engaged the autoplt when the 100 ft had was straight up. ATC eventually noticed my altitude and asked me to go back to 10000 ft. I really cannot remember when or how I got to 11000 ft. My guess is that #1 is probably right. The prior 2-3 weeks I had a lingering cold. Although I felt fine the day of the flight, it is possible that I was more susceptible to hypoxia. This might have led me to asking for 10000 ft, but thinking of 11000 ft? Since I had only 14 hours, in the plane and was still learning about the autoplt, #3 seems possible, but I doubt it. To conclude, I don't know or when I got to 11000 ft, ATC seems to have overlooked the problem for a while too, there were no separation or traffic conflict problems that I am aware of.
Original NASA ASRS Text
Title: ALTDEV ALT EXCURSION - PLT ENDS UP 1000 FT HIGHER THAN CLRNC AND IS UNABLE TO EXPLAIN HOW IT HAPPENED.
Narrative: I WAS FLYING THE RETURN LEG OF A ROUND TRIP TO (AUG) FROM (5B2). THE LEG TO AUG WAS FLOWN AT 11000 FT. WAS ON GND AT AUG FOR ABOUT 1 HR. THE RETURN FLT PLAN WAS: AUG, V- 39, NEETS, V-496, GFL, DIRECT 5B2, CRUISING ALT 8000 FT. AFTER CLBING TO 8000 FT, ASKED PORTLAND APCH FOR HIGHER BECAUSE 8000 FT PUT ME IN AND OUT OF CLOUD TOPS. AT XA00 HRS LCL MANCHESTER APCH ASKED ME MY ALT. SINCE I WAS FLYING WBOUND, I ASSUMED THAT I WAS AT 10000 FT. AUTOPLT ALT HOLD WAS ENGAGED AND THE 100 FT OF THE ALTIMETER WAS STRAIGHT UP. MHT SAID THEY SHOWED ME AT 11000 FT. WHY WAS I AT 11000 FT AND HOW AND WHEN DID I GET THERE?? POSSIBLE ANSWERS: -- WHEN I ASKED PORTLAND APCH FOR HIGHER, I ASKED AND RECEIVED 10000 FT BUT CLBED TO 11000 FT ( I HAD JUST FLOWN OUT TO AUG AT 11000 FT). I THEN CRUISED LEVEL AT 11000 FT FOR 3 MINS BEFORE ATC REALIZED I WAS 1000 FT OFF THE ASSIGNED ALT. -- I ASKED FOR AND WAS GIVEN 11000 FT, BUT ATC PUT 10000 FT ON MY FLT STRIP SINCE THAT IS A NORMAL WBOUND ALT. -- I ASKED FOR AND WAS GIVEN 10000 FT, CLBED TO 10000 FT, SET ALT HOLD ON AUTOPLT WHEN AT 10000 FT. THEN THE AUTOPLT DISENGAGED WHILE IN A SLIGHT TRIM UP CONDITION, RESULTING IN A VERY SLOW CLB TO 11000 FT. AS PLANE NEARED 11000 FT, I NOTICED THE AUTOPLT WAS DISENGAGED, SO WITHOUT CAREFULLY CHKING ALTIMETER, I RE- ENGAGED THE AUTOPLT WHEN THE 100 FT HAD WAS STRAIGHT UP. ATC EVENTUALLY NOTICED MY ALT AND ASKED ME TO GO BACK TO 10000 FT. I REALLY CANNOT REMEMBER WHEN OR HOW I GOT TO 11000 FT. MY GUESS IS THAT #1 IS PROBABLY RIGHT. THE PRIOR 2-3 WKS I HAD A LINGERING COLD. ALTHOUGH I FELT FINE THE DAY OF THE FLT, IT IS POSSIBLE THAT I WAS MORE SUSCEPTIBLE TO HYPOXIA. THIS MIGHT HAVE LED ME TO ASKING FOR 10000 FT, BUT THINKING OF 11000 FT? SINCE I HAD ONLY 14 HRS, IN THE PLANE AND WAS STILL LEARNING ABOUT THE AUTOPLT, #3 SEEMS POSSIBLE, BUT I DOUBT IT. TO CONCLUDE, I DON'T KNOW OR WHEN I GOT TO 11000 FT, ATC SEEMS TO HAVE OVERLOOKED THE PROB FOR A WHILE TOO, THERE WERE NO SEPARATION OR TFC CONFLICT PROBS THAT I AM AWARE OF.
Data retrieved from NASA's ASRS site as of July 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.