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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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B737-500 flight crew fails to make an altitude crossing. Advised ZSE controller and received some verbal admonition. Flight switched to sea approach, controller gave a new altitude assignment. Rptrs cite a late start of descent by the FMS.
| Attributes | |
| ACN | 373211 |
| Time | |
| Date | 199707 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : sea |
| State Reference | WA |
| Altitude | msl bound lower : 16000 msl bound upper : 20000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zse tracon : sea |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Route In Use | enroute other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : cfi pilot : commercial |
| Experience | flight time last 90 days : 120 flight time total : 5100 flight time type : 410 |
| ASRS Report | 373211 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 210 flight time total : 9500 flight time type : 2500 |
| ASRS Report | 373210 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
The autoplt did not start the descent to cross tawbn intersection at 16000 ft on time or as programmed. ATC instructed us to cross jawbn at 16000 ft. I did not xchk the descent computer in my head to insure its calculations were correct. About 15 mi from jawbn, we realized that we were not going to make jawbn at 16000 ft, and told ATC of this so she could vector us or hold us as necessary. She just said something to the effect of 'don't tell us you can make the altitude then find out you can't -- contact sea approach on XXX.xx.' approach then gave us a new altitude to descend to. Nothing more was said. As I see it, the main problem was I relied too much on the onboard computer without working through the calculations in my head. Also the comment and tone of the air traffic controller was not necessary since we gave her 15 mi notice to our situation. Supplemental information from acn 373210: autoplt, through pms, was set for this altitude. During briefing we noticed that the aircraft had started descent late and we would not make the crossing restr. Once again this shows that pilot vigilance over all aspects of aircraft should be maintained and that reliance on automation can get you in trouble if you're not backing it up using your own experience.
Original NASA ASRS Text
Title: B737-500 FLC FAILS TO MAKE AN ALT XING. ADVISED ZSE CTLR AND RECEIVED SOME VERBAL ADMONITION. FLT SWITCHED TO SEA APCH, CTLR GAVE A NEW ALT ASSIGNMENT. RPTRS CITE A LATE START OF DSCNT BY THE FMS.
Narrative: THE AUTOPLT DID NOT START THE DSCNT TO CROSS TAWBN INTXN AT 16000 FT ON TIME OR AS PROGRAMMED. ATC INSTRUCTED US TO CROSS JAWBN AT 16000 FT. I DID NOT XCHK THE DSCNT COMPUTER IN MY HEAD TO INSURE ITS CALCULATIONS WERE CORRECT. ABOUT 15 MI FROM JAWBN, WE REALIZED THAT WE WERE NOT GOING TO MAKE JAWBN AT 16000 FT, AND TOLD ATC OF THIS SO SHE COULD VECTOR US OR HOLD US AS NECESSARY. SHE JUST SAID SOMETHING TO THE EFFECT OF 'DON'T TELL US YOU CAN MAKE THE ALT THEN FIND OUT YOU CAN'T -- CONTACT SEA APCH ON XXX.XX.' APCH THEN GAVE US A NEW ALT TO DSND TO. NOTHING MORE WAS SAID. AS I SEE IT, THE MAIN PROB WAS I RELIED TOO MUCH ON THE ONBOARD COMPUTER WITHOUT WORKING THROUGH THE CALCULATIONS IN MY HEAD. ALSO THE COMMENT AND TONE OF THE AIR TFC CTLR WAS NOT NECESSARY SINCE WE GAVE HER 15 MI NOTICE TO OUR SIT. SUPPLEMENTAL INFO FROM ACN 373210: AUTOPLT, THROUGH PMS, WAS SET FOR THIS ALT. DURING BRIEFING WE NOTICED THAT THE ACFT HAD STARTED DSCNT LATE AND WE WOULD NOT MAKE THE XING RESTR. ONCE AGAIN THIS SHOWS THAT PLT VIGILANCE OVER ALL ASPECTS OF ACFT SHOULD BE MAINTAINED AND THAT RELIANCE ON AUTOMATION CAN GET YOU IN TROUBLE IF YOU'RE NOT BACKING IT UP USING YOUR OWN EXPERIENCE.
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.