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Government pilots on a training cross country flight inadvertently allowed the altitude to decrease while planning a deviation around a thunderstorm build-up resulting in less than standard separation with an air carrier medium large transport aircraft.
| Attributes | |
| ACN | 208636 |
| Time | |
| Date | 199204 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : elp |
| State Reference | TX |
| Altitude | msl bound lower : 38700 msl bound upper : 39000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zab |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | other |
| Make Model Name | Military Trainer |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 90 flight time total : 7000 flight time type : 90 |
| ASRS Report | 208636 |
| Person 2 | |
| Affiliation | government other |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 90 flight time total : 5000 flight time type : 90 |
| ASRS Report | 208449 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Miss Distance | unspecified : 18000 |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Flying en route to el paso international at FL390, set off the altitude alarm in ZAB. 2 crew members were in the aircraft and the rear cockpit pilot was flying at the time of the occurrence. The rear cockpit pilot allowed himself to be distracted while trying to decide whether to fly to the left or the right of a large buildup. A shallow descent started and was noticed first by the front cockpit pilot who called 'check altitude' over the intercom system. The PF started to make an input at the same time as the front cockpit pilot took control of the aircraft and aggressively put the aircraft in a climb back to FL390. While the altitude excursion was occurring, an airliner was within approximately 3 NM. The front cockpit pilot had a visual on the jet during the excursion. The loss altitude achieved was no lower than FL387. The remainder of the flight to el paso international was uneventful. This excursion occurred due to distraction outside the cockpit (i.e., the thunderstorm and decision for maneuvering). It could have been prevented by maintaining a better INS xchk.
Original NASA ASRS Text
Title: GOV PLTS ON A TRAINING XCOUNTRY FLT INADVERTENTLY ALLOWED THE ALT TO DECREASE WHILE PLANNING A DEV AROUND A TSTM BUILD-UP RESULTING IN LTSS WITH AN ACR MLG ACFT.
Narrative: FLYING ENRTE TO EL PASO INTL AT FL390, SET OFF THE ALT ALARM IN ZAB. 2 CREW MEMBERS WERE IN THE ACFT AND THE REAR COCKPIT PLT WAS FLYING AT THE TIME OF THE OCCURRENCE. THE REAR COCKPIT PLT ALLOWED HIMSELF TO BE DISTRACTED WHILE TRYING TO DECIDE WHETHER TO FLY TO THE L OR THE R OF A LARGE BUILDUP. A SHALLOW DSCNT STARTED AND WAS NOTICED FIRST BY THE FRONT COCKPIT PLT WHO CALLED 'CHK ALT' OVER THE INTERCOM SYS. THE PF STARTED TO MAKE AN INPUT AT THE SAME TIME AS THE FRONT COCKPIT PLT TOOK CTL OF THE ACFT AND AGGRESSIVELY PUT THE ACFT IN A CLB BACK TO FL390. WHILE THE ALT EXCURSION WAS OCCURRING, AN AIRLINER WAS WITHIN APPROX 3 NM. THE FRONT COCKPIT PLT HAD A VISUAL ON THE JET DURING THE EXCURSION. THE LOSS ALT ACHIEVED WAS NO LOWER THAN FL387. THE REMAINDER OF THE FLT TO EL PASO INTL WAS UNEVENTFUL. THIS EXCURSION OCCURRED DUE TO DISTR OUTSIDE THE COCKPIT (I.E., THE TSTM AND DECISION FOR MANEUVERING). IT COULD HAVE BEEN PREVENTED BY MAINTAINING A BETTER INS XCHK.
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.