|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : mvy|
|Altitude||msl bound lower : 3750|
msl bound upper : 4000
|Controlling Facilities||artcc : zbw|
tracon : fmh
|Operator||general aviation : corporate|
|Make Model Name||Any Unknown or Unlisted Aircraft Manufacturer|
|Operating Under FAR Part||Part 91|
|Flight Phase||cruise other|
|Function||flight crew : single pilot|
|Qualification||pilot : atp|
pilot : cfi
pilot : commercial
|Experience||flight time last 90 days : 75|
flight time total : 13000
flight time type : 600
|Affiliation||government : faa|
|Function||controller : approach|
|Qualification||controller : radar|
|Anomaly||aircraft equipment problem : less severe|
other anomaly other
|Independent Detector||other controllera|
|Resolutory Action||flight crew : overcame equipment problem|
|Air Traffic Incident||other|
I had been cleared to climb to 4000 ft. I arrived at 4000 ft on the altimeter. After a few mins otis approach asked me if I was showing 4000 ft. I acknowledged that I was. They asked if I had 29.95 on the altimeter. I acknowledged yes. They said they were showing 3750 ft. I said I was at 4000 ft indicated. They said have the altimeter checked. They changed me over to ZBW to check my altitude on the second altimeter and second transponder. They said they were showing 4000 ft. I concurred with them. The remaining flight was ok.
Original NASA ASRS Text
Title: TWIN CORPORATE TURBOPROP APPEARED TO BE EXPERIENCING AN ALTDEV ALT UNDERSHOT IN CLB. UPON FURTHER INVESTIGATION IT WAS FOUND THAT #1 XPONDER ALT ENCODER WAS FAULTY, PLT SWITCHED TO #2 XPONDER.
Narrative: I HAD BEEN CLRED TO CLB TO 4000 FT. I ARRIVED AT 4000 FT ON THE ALTIMETER. AFTER A FEW MINS OTIS APCH ASKED ME IF I WAS SHOWING 4000 FT. I ACKNOWLEDGED THAT I WAS. THEY ASKED IF I HAD 29.95 ON THE ALTIMETER. I ACKNOWLEDGED YES. THEY SAID THEY WERE SHOWING 3750 FT. I SAID I WAS AT 4000 FT INDICATED. THEY SAID HAVE THE ALTIMETER CHKED. THEY CHANGED ME OVER TO ZBW TO CHK MY ALT ON THE SECOND ALTIMETER AND SECOND XPONDER. THEY SAID THEY WERE SHOWING 4000 FT. I CONCURRED WITH THEM. THE REMAINING FLT WAS OK.
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.