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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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F100 flight crew descends through FL260, thinking that they had been cleared to FL240. Controller, prior to their going through FL260 reiterates their altitude restr and flight crew thinks that this reminder is a speed restr for 260 KTS. Potential conflict ensues with TCASII RA being the escape valve. Had controller mentioned traffic the scenario might have been altered.
| Attributes | |
| ACN | 376760 |
| Time | |
| Date | 199708 |
| Day | Fri |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : djb |
| State Reference | OH |
| Altitude | msl bound lower : 25700 msl bound upper : 26000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob |
| Operator | common carrier : air carrier |
| Make Model Name | Fokker 100 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other descent other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | general aviation : corporate |
| Make Model Name | HS 125 Series 1-600 |
| Operating Under FAR Part | other : unknown |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 120 flight time total : 11000 flight time type : 3000 |
| ASRS Report | 376760 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 130 flight time total : 8000 flight time type : 2500 |
| ASRS Report | 376685 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : required legal separation non adherence : clearance other anomaly other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other controllera |
| Resolutory Action | flight crew : exited adverse environment flight crew : took evasive action other |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 4200 vertical : 500 |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
While cruising at FL280 center issued a descent clearance to FL240. During descent ATC issued a request to stop descent at FL260. Cockpit crew acknowledged to what it believed to be a request to slow to 260 KTS for traffic separation. At approximately FL255 aircraft received a TA and followed by an RA, to which it responded. ATC then advised that the aircraft had been cleared to FL260, not FL240. Supplemental information from acn 376685: while approaching FL260 ZOB issued 'maintain 260 KTS.'
Original NASA ASRS Text
Title: F100 FLC DSNDS THROUGH FL260, THINKING THAT THEY HAD BEEN CLRED TO FL240. CTLR, PRIOR TO THEIR GOING THROUGH FL260 REITERATES THEIR ALT RESTR AND FLC THINKS THAT THIS REMINDER IS A SPD RESTR FOR 260 KTS. POTENTIAL CONFLICT ENSUES WITH TCASII RA BEING THE ESCAPE VALVE. HAD CTLR MENTIONED TFC THE SCENARIO MIGHT HAVE BEEN ALTERED.
Narrative: WHILE CRUISING AT FL280 CTR ISSUED A DSCNT CLRNC TO FL240. DURING DSCNT ATC ISSUED A REQUEST TO STOP DSCNT AT FL260. COCKPIT CREW ACKNOWLEDGED TO WHAT IT BELIEVED TO BE A REQUEST TO SLOW TO 260 KTS FOR TFC SEPARATION. AT APPROX FL255 ACFT RECEIVED A TA AND FOLLOWED BY AN RA, TO WHICH IT RESPONDED. ATC THEN ADVISED THAT THE ACFT HAD BEEN CLRED TO FL260, NOT FL240. SUPPLEMENTAL INFO FROM ACN 376685: WHILE APCHING FL260 ZOB ISSUED 'MAINTAIN 260 KTS.'
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.