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Flight crew of a C560 experiences an altitude excursion during a momentary lapse of vigilance and distraction.
| Attributes | |
| ACN | 400780 |
| Time | |
| Date | 199804 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : pgs |
| State Reference | AZ |
| Altitude | msl bound lower : 30300 msl bound upper : 31000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla |
| Operator | general aviation : corporate |
| Make Model Name | Citation V |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 3500 flight time type : 225 |
| ASRS Report | 400780 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 3800 flight time type : 1000 |
| ASRS Report | 400779 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance non adherence other |
| Independent Detector | 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:
En route to las, first officer left cockpit momentarily. Captain was PF during this time. Captain received ATC instructions to descend to FL310. He then selected the flight director to his side and proceeded. ATC then cleared to crowe intersection on the runway 25L localizer. Captain was unable to locate crowe and the first officer was returning to the cockpit. Captain told first officer that he had the flight director on his side and then switched it back to the first officer. This action clears the autoplt. The first officer then re-selected navigation on the mode controller. At this point the first officer proceeded to help the captain find crowe intersection. Both pilots were of the mind that the autoplt was 'flying' the airplane. However a moment later we both noticed that the airplane was 600- 700 ft low. We immediately climbed back to FL310. At this time ATC asked us to verify our assigned altitude and then cleared us down to FL240. The breakdown was when the flight director was put back to the right side. The first officer only selected 'navigation' and not 'altitude.' the first officer then diverted his attention to helping the captain find 'crowe.' this became a classic, 'no one is flying the airplane.' tighter SOP in regards to flight director switches may have prevented this. Also the crew should make sure someone was 'flying the plane' at all times.
Original NASA ASRS Text
Title: FLC OF A C560 EXPERIENCES AN ALT EXCURSION DURING A MOMENTARY LAPSE OF VIGILANCE AND DISTR.
Narrative: ENRTE TO LAS, FO LEFT COCKPIT MOMENTARILY. CAPT WAS PF DURING THIS TIME. CAPT RECEIVED ATC INSTRUCTIONS TO DSND TO FL310. HE THEN SELECTED THE FLT DIRECTOR TO HIS SIDE AND PROCEEDED. ATC THEN CLRED TO CROWE INTXN ON THE RWY 25L LOC. CAPT WAS UNABLE TO LOCATE CROWE AND THE FO WAS RETURNING TO THE COCKPIT. CAPT TOLD FO THAT HE HAD THE FLT DIRECTOR ON HIS SIDE AND THEN SWITCHED IT BACK TO THE FO. THIS ACTION CLRS THE AUTOPLT. THE FO THEN RE-SELECTED NAV ON THE MODE CTLR. AT THIS POINT THE FO PROCEEDED TO HELP THE CAPT FIND CROWE INTXN. BOTH PLTS WERE OF THE MIND THAT THE AUTOPLT WAS 'FLYING' THE AIRPLANE. HOWEVER A MOMENT LATER WE BOTH NOTICED THAT THE AIRPLANE WAS 600- 700 FT LOW. WE IMMEDIATELY CLBED BACK TO FL310. AT THIS TIME ATC ASKED US TO VERIFY OUR ASSIGNED ALT AND THEN CLRED US DOWN TO FL240. THE BREAKDOWN WAS WHEN THE FLT DIRECTOR WAS PUT BACK TO THE R SIDE. THE FO ONLY SELECTED 'NAV' AND NOT 'ALT.' THE FO THEN DIVERTED HIS ATTN TO HELPING THE CAPT FIND 'CROWE.' THIS BECAME A CLASSIC, 'NO ONE IS FLYING THE AIRPLANE.' TIGHTER SOP IN REGARDS TO FLT DIRECTOR SWITCHES MAY HAVE PREVENTED THIS. ALSO THE CREW SHOULD MAKE SURE SOMEONE WAS 'FLYING THE PLANE' AT ALL TIMES.
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.