37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Attributes | |
ACN | 394740 |
Time | |
Date | 199802 |
Day | Tue |
Local Time Of Day | 0601 To 1200 |
Place | |
Locale Reference | airport : dca |
State Reference | DC |
Altitude | msl bound lower : 19000 msl bound upper : 19400 |
Environment | |
Flight Conditions | VMC |
Light | Dawn |
Aircraft 1 | |
Controlling Facilities | artcc : dca tower : clt |
Operator | common carrier : air carrier |
Make Model Name | B757 Undifferentiated or Other Model |
Operating Under FAR Part | Part 121 |
Navigation In Use | Other Other |
Flight Phase | climbout : intermediate altitude cruise other |
Route In Use | departure other enroute : on vectors |
Flight Plan | IFR |
Person 1 | |
Affiliation | company : air carrier |
Function | flight crew : captain oversight : pic |
Qualification | pilot : flight engineer pilot : atp |
Experience | flight time last 90 days : 100 flight time total : 8600 flight time type : 1500 |
ASRS Report | 394740 |
Person 2 | |
Affiliation | company : air carrier |
Function | flight crew : first officer |
Qualification | pilot : commercial pilot : instrument |
Events | |
Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance other anomaly other |
Independent Detector | aircraft equipment other aircraft equipment : unspecified other controllera |
Resolutory Action | flight crew : returned to intended course or assigned course other |
Consequence | Other |
Supplementary | |
Primary Problem | Aircraft |
Air Traffic Incident | Pilot Deviation other |
Narrative:
Captain was hand flying. After contacting departure we were cleared to 10000 ft on a north heading. Passing through 8300 ft MSL, ATC told us to level at 8000 ft. Climb was stopped and starting descent to 8000 ft we were reclred to 10000 ft with a 120 degree turn towards the east, away from another aircraft at 10000 ft. ZDC later cleared us up to FL190. The altimeter setting was 29.52. Due to traffic, autoplt was engaged. The aircraft was light and 'altitude capture' occurred at 17000 ft. At 17300 ft altimeter was reset to 29.92. Reaching FL190 aircraft leveled off. However, it continued up to FL193, at which time the altitude alert signaled us that a deviation had occurred. ATC also questioned us because they showed us at FL194. In fact, by this time, we touched FL194. Aircraft was manually flown back to FL190 which was the altitude set all along in the mode selector panel. Because the airplane had been on autoplt and we were looking outside for traffic and the sun was rising in our eyes, I failed to notice the altitude deviation. We called our maintenance base, suspecting that the large altimeter difference was too large for the airplane system to accommodate in just a few hundred ft (going through 17000 ft to FL190), particularly after engaging in the altitude capture mode. They thought so, too. This is something to really pay attention to when transition levels and leveloffs near them involve large differences in altimeter changes, especially when not hand flying, but relying on automated system. I don't think there was a conflict with any other aircraft.
Original NASA ASRS Text
Title: A B757 OVERSHOT ITS ASSIGNED ALT OF FL190 BY 400 FT. ACFT HAD BEEN ON AUTOPLT AND AT A HIGH RATE OF CLB.
Narrative: CAPT WAS HAND FLYING. AFTER CONTACTING DEP WE WERE CLRED TO 10000 FT ON A N HDG. PASSING THROUGH 8300 FT MSL, ATC TOLD US TO LEVEL AT 8000 FT. CLB WAS STOPPED AND STARTING DSCNT TO 8000 FT WE WERE RECLRED TO 10000 FT WITH A 120 DEG TURN TOWARDS THE E, AWAY FROM ANOTHER ACFT AT 10000 FT. ZDC LATER CLRED US UP TO FL190. THE ALTIMETER SETTING WAS 29.52. DUE TO TFC, AUTOPLT WAS ENGAGED. THE ACFT WAS LIGHT AND 'ALT CAPTURE' OCCURRED AT 17000 FT. AT 17300 FT ALTIMETER WAS RESET TO 29.92. REACHING FL190 ACFT LEVELED OFF. HOWEVER, IT CONTINUED UP TO FL193, AT WHICH TIME THE ALT ALERT SIGNALED US THAT A DEV HAD OCCURRED. ATC ALSO QUESTIONED US BECAUSE THEY SHOWED US AT FL194. IN FACT, BY THIS TIME, WE TOUCHED FL194. ACFT WAS MANUALLY FLOWN BACK TO FL190 WHICH WAS THE ALT SET ALL ALONG IN THE MODE SELECTOR PANEL. BECAUSE THE AIRPLANE HAD BEEN ON AUTOPLT AND WE WERE LOOKING OUTSIDE FOR TFC AND THE SUN WAS RISING IN OUR EYES, I FAILED TO NOTICE THE ALTDEV. WE CALLED OUR MAINT BASE, SUSPECTING THAT THE LARGE ALTIMETER DIFFERENCE WAS TOO LARGE FOR THE AIRPLANE SYS TO ACCOMMODATE IN JUST A FEW HUNDRED FT (GOING THROUGH 17000 FT TO FL190), PARTICULARLY AFTER ENGAGING IN THE ALT CAPTURE MODE. THEY THOUGHT SO, TOO. THIS IS SOMETHING TO REALLY PAY ATTN TO WHEN TRANSITION LEVELS AND LEVELOFFS NEAR THEM INVOLVE LARGE DIFFERENCES IN ALTIMETER CHANGES, ESPECIALLY WHEN NOT HAND FLYING, BUT RELYING ON AUTOMATED SYS. I DON'T THINK THERE WAS A CONFLICT WITH ANY OTHER ACFT.
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.