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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Captain of an large transport air carrier aircraft turned too soon on a SID departure and overshot assigned altitude due to attempting to have the automatic flight system control the aircraft. FMC programming problem, turned aircraft sooner than ATC expected.
| Attributes | |
| ACN | 251307 |
| Time | |
| Date | 199309 |
| Day | Thu |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : sea |
| State Reference | WA |
| Altitude | msl bound lower : 4000 msl bound upper : 9500 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : sea |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure other departure sid : sid enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 12000 flight time type : 1500 |
| ASRS Report | 251307 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance other spatial deviation |
| Independent Detector | atc equipment other atc equipment : unspecified other controllera other flight crewa |
| Resolutory Action | controller : issued new clearance 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:
Departing sea (captain flying) he used LNAV to intercept radial. On the SID there is a 90 degree turn at 8 NM. The automated system (LNAV) leads the turn significantly in order to roll out on the new radial/course. We were cleared to 9000 ft and climbing rapidly as we started the turn. Departure control cleared us to 15000 ft. He then told us we were turning early and to turn back to 340 degree heading and to maintain 9000 ft. We acknowledged and shortly thereafter he gave us a heading of 070 degrees and 15000 ft again. About the time we were rolling out on 070 degrees and trying to figure out what went wrong on the SID we were again given 9000 ft. The aircraft was now on autoplt and rapidly approaching 9000 ft on the way to 15000 ft. I set 9000 ft back in the window and the captain disconnected the autoplt to level at 9000 ft but overshot to about 9500 ft. There was no traffic conflict that we were aware of but a lot of confusion in a critical phase of flight. I suggest using raw data in such a situation to make sure the turn doesn't begin until 8 DME and make sure the automatic-system/magic doesn't confuse or get you in trouble.
Original NASA ASRS Text
Title: CAPT OF AN LGT ACR ACFT TURNED TOO SOON ON A SID DEP AND OVERSHOT ASSIGNED ALT DUE TO ATTEMPTING TO HAVE THE AUTOMATIC FLT SYS CTL THE ACFT. FMC PROGRAMMING PROB, TURNED ACFT SOONER THAN ATC EXPECTED.
Narrative: DEPARTING SEA (CAPT FLYING) HE USED LNAV TO INTERCEPT RADIAL. ON THE SID THERE IS A 90 DEG TURN AT 8 NM. THE AUTOMATED SYS (LNAV) LEADS THE TURN SIGNIFICANTLY IN ORDER TO ROLL OUT ON THE NEW RADIAL/COURSE. WE WERE CLRED TO 9000 FT AND CLBING RAPIDLY AS WE STARTED THE TURN. DEP CTL CLRED US TO 15000 FT. HE THEN TOLD US WE WERE TURNING EARLY AND TO TURN BACK TO 340 DEG HDG AND TO MAINTAIN 9000 FT. WE ACKNOWLEDGED AND SHORTLY THEREAFTER HE GAVE US A HDG OF 070 DEGS AND 15000 FT AGAIN. ABOUT THE TIME WE WERE ROLLING OUT ON 070 DEGS AND TRYING TO FIGURE OUT WHAT WENT WRONG ON THE SID WE WERE AGAIN GIVEN 9000 FT. THE ACFT WAS NOW ON AUTOPLT AND RAPIDLY APCHING 9000 FT ON THE WAY TO 15000 FT. I SET 9000 FT BACK IN THE WINDOW AND THE CAPT DISCONNECTED THE AUTOPLT TO LEVEL AT 9000 FT BUT OVERSHOT TO ABOUT 9500 FT. THERE WAS NO TFC CONFLICT THAT WE WERE AWARE OF BUT A LOT OF CONFUSION IN A CRITICAL PHASE OF FLT. I SUGGEST USING RAW DATA IN SUCH A SIT TO MAKE SURE THE TURN DOESN'T BEGIN UNTIL 8 DME AND MAKE SURE THE AUTO-SYS/MAGIC DOESN'T CONFUSE OR GET YOU IN TROUBLE.
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.