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WX factors create need for speed deviation, resulting in a non adherence to ATC clearance instruction.
| Attributes | |
| ACN | 259661 |
| Time | |
| Date | 199312 |
| Day | Tue |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : aqn |
| State Reference | TX |
| Altitude | msl bound lower : 19000 msl bound upper : 25000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zfw |
| Operator | general aviation : corporate |
| Make Model Name | Small Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : captain instruction : trainee |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 35 flight time total : 3145 flight time type : 7 |
| ASRS Report | 259661 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : first officer observation : company check pilot oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : critical inflight encounter : weather inflight encounter other non adherence : clearance other anomaly |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem flight crew : exited adverse environment flight crew : became reoriented |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Weather |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Descending from FL410 to 11000 ft controller stated maintain 280 KTS. I advised unable 280. Maximum speed was (vmo 263) controller requests post forward speed. Descending through FL250, moderate ice and moderate turbulence. Slowed to 180 KTS and kept power on N2 at 73 percent for ice protection. Shortly thereafter I got a 'roll' flag on eadi (altitude indicator) advising the comparator detected a discrepancy of 76 degrees between pilot and copilot gyro. Autoplt automatically disconnects as I was busy hand flying airplane through ice and turbulence trying to decide which gyro was accurate, I had other pilot communicate with ATC. Other pilot took a couple of mins to get in loop with ATC. For sure we slowed below assigned airspeed, but I believe we made our crossing altitude. Broke out of clouds and continued without any incident.
Original NASA ASRS Text
Title: WX FACTORS CREATE NEED FOR SPD DEV, RESULTING IN A NON ADHERENCE TO ATC CLRNC INSTRUCTION.
Narrative: DSNDING FROM FL410 TO 11000 FT CTLR STATED MAINTAIN 280 KTS. I ADVISED UNABLE 280. MAX SPD WAS (VMO 263) CTLR REQUESTS POST FORWARD SPD. DSNDING THROUGH FL250, MODERATE ICE AND MODERATE TURB. SLOWED TO 180 KTS AND KEPT PWR ON N2 AT 73 PERCENT FOR ICE PROTECTION. SHORTLY THEREAFTER I GOT A 'ROLL' FLAG ON EADI (ALT INDICATOR) ADVISING THE COMPARATOR DETECTED A DISCREPANCY OF 76 DEGS BTWN PLT AND COPLT GYRO. AUTOPLT AUTOMATICALLY DISCONNECTS AS I WAS BUSY HAND FLYING AIRPLANE THROUGH ICE AND TURB TRYING TO DECIDE WHICH GYRO WAS ACCURATE, I HAD OTHER PLT COMMUNICATE WITH ATC. OTHER PLT TOOK A COUPLE OF MINS TO GET IN LOOP WITH ATC. FOR SURE WE SLOWED BELOW ASSIGNED AIRSPD, BUT I BELIEVE WE MADE OUR XING ALT. BROKE OUT OF CLOUDS AND CONTINUED WITHOUT ANY INCIDENT.
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.