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Apparent mis-use (programming) of FMS leads to altitude crossing restriction not being met by advtech air carrier widebody transport.
| Attributes | |
| ACN | 163948 |
| Time | |
| Date | 199011 |
| Day | Mon |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : lax |
| State Reference | CA |
| Altitude | msl bound lower : 13000 msl bound upper : 13000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : lax |
| Operator | common carrier : air carrier |
| Make Model Name | Widebody, Low Wing, 4 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | descent : approach descent other |
| Route In Use | arrival : profile descent arrival other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 115 flight time total : 20000 flight time type : 241 |
| ASRS Report | 163948 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | altitude deviation : crossing restriction not met conflict : airborne less severe non adherence : clearance |
| Independent Detector | other flight crewa |
| Resolutory Action | other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
At completion of 9 1/2 hour 'back of the clock' ocean crossing, we set up flight management computer for VNAV descent into lax. Initially we had trouble getting lax center to commit to type of approach, finally were given 'profile descent 25/24' which really doesn't say much since we need a runway for FMC to complete VNAV computations. Copilot was flying but couldn't resist executing his own inputs into the FMC, I should have corrected him then but he'd been doing a great job up 'till then, and my desire to be the 'good guy' and let him do his own thing led me to overlook this breech of SOP. As I finished my captain chores (ATIS, talking to cabin, NOTAM review, etc), I noticed that VNAV readout showed us 9000' high north the profile. Since I really wasn't sure of his last entry into the FMC I assumed it was in error and started calculating my own analysis of our descent. My 'in head' calculations were slow, had to start over several times but as we approached fim it was obvious that, yes we were high, very high. I communicated this to the copilot, at which time he started messing with his CDU again, still in autoplt VNAV descent. I finally suggested that he throw out the spoilers and get off the autoplt, fly the airplane to make the profile xings. The remaining approach ended up being a real screamer, being high, fast and wide all the way down. As we turned on final we over shot runway 25R and flew in front of an medium large transport Y on approach to runway 25L. Corrective action: don't assume the 'ace' you've been flying with for 6 days will remain an ace after a back of the clock flight. Realize that 'stuff happens', especially when tired. In fact don't even assume your own analysis of the situation is correct. I'm sure my copilot would have an entirely different 'his side' of this story. In fact, it was our relief pilot in the jump seat who saved us.
Original NASA ASRS Text
Title: APPARENT MIS-USE (PROGRAMMING) OF FMS LEADS TO ALT CROSSING RESTRICTION NOT BEING MET BY ADVTECH ACR WDB.
Narrative: AT COMPLETION OF 9 1/2 HR 'BACK OF THE CLOCK' OCEAN XING, WE SET UP FLT MGMNT COMPUTER FOR VNAV DSNT INTO LAX. INITIALLY WE HAD TROUBLE GETTING LAX CTR TO COMMIT TO TYPE OF APCH, FINALLY WERE GIVEN 'PROFILE DSNT 25/24' WHICH REALLY DOESN'T SAY MUCH SINCE WE NEED A RWY FOR FMC TO COMPLETE VNAV COMPUTATIONS. COPLT WAS FLYING BUT COULDN'T RESIST EXECUTING HIS OWN INPUTS INTO THE FMC, I SHOULD HAVE CORRECTED HIM THEN BUT HE'D BEEN DOING A GREAT JOB UP 'TILL THEN, AND MY DESIRE TO BE THE 'GOOD GUY' AND LET HIM DO HIS OWN THING LED ME TO OVERLOOK THIS BREECH OF SOP. AS I FINISHED MY CAPT CHORES (ATIS, TALKING TO CABIN, NOTAM REVIEW, ETC), I NOTICED THAT VNAV READOUT SHOWED US 9000' HIGH N THE PROFILE. SINCE I REALLY WASN'T SURE OF HIS LAST ENTRY INTO THE FMC I ASSUMED IT WAS IN ERROR AND STARTED CALCULATING MY OWN ANALYSIS OF OUR DSNT. MY 'IN HEAD' CALCULATIONS WERE SLOW, HAD TO START OVER SEVERAL TIMES BUT AS WE APCHED FIM IT WAS OBVIOUS THAT, YES WE WERE HIGH, VERY HIGH. I COMMUNICATED THIS TO THE COPLT, AT WHICH TIME HE STARTED MESSING WITH HIS CDU AGAIN, STILL IN AUTOPLT VNAV DSNT. I FINALLY SUGGESTED THAT HE THROW OUT THE SPOILERS AND GET OFF THE AUTOPLT, FLY THE AIRPLANE TO MAKE THE PROFILE XINGS. THE REMAINING APCH ENDED UP BEING A REAL SCREAMER, BEING HIGH, FAST AND WIDE ALL THE WAY DOWN. AS WE TURNED ON FINAL WE OVER SHOT RWY 25R AND FLEW IN FRONT OF AN MLG Y ON APCH TO RWY 25L. CORRECTIVE ACTION: DON'T ASSUME THE 'ACE' YOU'VE BEEN FLYING WITH FOR 6 DAYS WILL REMAIN AN ACE AFTER A BACK OF THE CLOCK FLT. REALIZE THAT 'STUFF HAPPENS', ESPECIALLY WHEN TIRED. IN FACT DON'T EVEN ASSUME YOUR OWN ANALYSIS OF THE SITUATION IS CORRECT. I'M SURE MY COPLT WOULD HAVE AN ENTIRELY DIFFERENT 'HIS SIDE' OF THIS STORY. IN FACT, IT WAS OUR RELIEF PLT IN THE JUMP SEAT WHO SAVED US.
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.