 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Flight crew of air carrier medium large transport aircraft inadvertently overshot descent altitude due to the aircraft's autoplt altitude setting problem.
| Attributes | |
| ACN | 240798 |
| Time | |
| Date | 199305 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : lga |
| State Reference | NY |
| Altitude | msl bound lower : 6300 msl bound upper : 7000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Route In Use | arrival other arrival star : star enroute : on vectors enroute airway : n90 |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : instrument pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 220 flight time total : 3400 flight time type : 1300 |
| ASRS Report | 240798 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : commercial pilot : flight engineer pilot : instrument |
| Experience | flight time last 90 days : 200 flight time total : 22000 flight time type : 1820 |
| ASRS Report | 240964 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance |
| Independent Detector | atc equipment other atc equipment : unspecified 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:
During descent to klga on flight X, controller instructed us to descend from 12000 ft to 7000 ft while on the milton 7 arrival. Autoplt was on RNAV tracking. I set 7000 ft into altitude window and captain verified setting. Passing about 8500 ft we began a turn. I checked progress on the unfamiliar arrival while monitoring descent. Controller then notified us to maintain 7000 ft. Our altitude was 6500 ft and both of us noticed 6000 ft now in the altitude window. I hand flew the aircraft back to 7000 ft and continued the arrival. No traffic conflict. It appears that the digital altitude window was set between the detents (which are 'soft' in this equipment) and slipped after being set. Though I was monitoring the descent, distracting factors made me forget the original transmission and made me think it was the 6000 ft now indicated.
Original NASA ASRS Text
Title: FLC OF ACR MLG ACFT INADVERTENTLY OVERSHOT DSCNT ALT DUE TO THE ACFT'S AUTOPLT ALT SETTING PROB.
Narrative: DURING DSCNT TO KLGA ON FLT X, CTLR INSTRUCTED US TO DSND FROM 12000 FT TO 7000 FT WHILE ON THE MILTON 7 ARR. AUTOPLT WAS ON RNAV TRACKING. I SET 7000 FT INTO ALT WINDOW AND CAPT VERIFIED SETTING. PASSING ABOUT 8500 FT WE BEGAN A TURN. I CHKED PROGRESS ON THE UNFAMILIAR ARR WHILE MONITORING DSCNT. CTLR THEN NOTIFIED US TO MAINTAIN 7000 FT. OUR ALT WAS 6500 FT AND BOTH OF US NOTICED 6000 FT NOW IN THE ALT WINDOW. I HAND FLEW THE ACFT BACK TO 7000 FT AND CONTINUED THE ARR. NO TFC CONFLICT. IT APPEARS THAT THE DIGITAL ALT WINDOW WAS SET BTWN THE DETENTS (WHICH ARE 'SOFT' IN THIS EQUIP) AND SLIPPED AFTER BEING SET. THOUGH I WAS MONITORING THE DSCNT, DISTRACTING FACTORS MADE ME FORGET THE ORIGINAL XMISSION AND MADE ME THINK IT WAS THE 6000 FT NOW INDICATED.
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.