 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Autoplt of mlt, in combination with the INS system to which it was coupled issues a steep, uncommanded turn and descent.
| Attributes | |
| ACN | 154044 |
| Time | |
| Date | 199008 |
| Day | Sun |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | atc facility : mlg |
| State Reference | UT |
| Altitude | msl bound lower : 20000 msl bound upper : 21000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zlc |
| Operator | other |
| Make Model Name | Military Transport |
| Flight Phase | cruise other |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : military |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : commercial pilot : atp pilot : instrument |
| Experience | flight time last 90 days : 100 flight time total : 2300 flight time type : 1000 |
| ASRS Report | 154044 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
While flying INS direct to mlf 264/26 autoplt commanded a 45 degree bank turn to the right. Both pilots immediately examined the autoplt panel. Aircraft was still coupled to INS with altitude hold on. While verifying INS with navigator, the plane was noticed to be in an uncommanded descent. Autoplt was immediately disconnected and the aircraft was returned to level flight and correct course. Altitude loss was 1000' due to crew was slow to respond and recognize altitude loss due to fact that, checking INS for reason for uncommanded turn and altitude hold function of autoplt was indicating that it was still working properly during the turn. Recommendations, autoplt should be disconnected when failure of INS or any function of autoplt is inoperative.
Original NASA ASRS Text
Title: AUTOPLT OF MLT, IN COMBINATION WITH THE INS SYSTEM TO WHICH IT WAS COUPLED ISSUES A STEEP, UNCOMMANDED TURN AND DESCENT.
Narrative: WHILE FLYING INS DIRECT TO MLF 264/26 AUTOPLT COMMANDED A 45 DEG BANK TURN TO THE R. BOTH PLTS IMMEDIATELY EXAMINED THE AUTOPLT PANEL. ACFT WAS STILL COUPLED TO INS WITH ALT HOLD ON. WHILE VERIFYING INS WITH NAVIGATOR, THE PLANE WAS NOTICED TO BE IN AN UNCOMMANDED DSNT. AUTOPLT WAS IMMEDIATELY DISCONNECTED AND THE ACFT WAS RETURNED TO LEVEL FLT AND CORRECT COURSE. ALT LOSS WAS 1000' DUE TO CREW WAS SLOW TO RESPOND AND RECOGNIZE ALT LOSS DUE TO FACT THAT, CHKING INS FOR REASON FOR UNCOMMANDED TURN AND ALT HOLD FUNCTION OF AUTOPLT WAS INDICATING THAT IT WAS STILL WORKING PROPERLY DURING THE TURN. RECOMMENDATIONS, AUTOPLT SHOULD BE DISCONNECTED WHEN FAILURE OF INS OR ANY FUNCTION OF AUTOPLT IS INOPERATIVE.
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.