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A lear 35 flight crew was reclred to an altitude then directed to descend to the previous altitude by ZLA.
| Attributes | |
| ACN | 451210 |
| Time | |
| Date | 199910 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : vtu.vortac |
| State Reference | CA |
| Altitude | msl bound lower : 10000 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla.artcc |
| Operator | general aviation : corporate |
| Make Model Name | Learjet 35 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zla.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : corporate |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 160 flight time total : 12000 flight time type : 1100 |
| ASRS Report | 451210 |
| Person 2 | |
| Affiliation | company : corporate |
| Function | flight crew : first officer |
| Qualification | pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 210 flight time total : 3620 flight time type : 160 |
| ASRS Report | 451440 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | flight crew : returned to assigned altitude |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance ATC Human Performance |
| Primary Problem | Ambiguous |
| Air Traffic Incident | Pilot Deviation |
Narrative:
It was a normal day, visibility was more than 10 mi and clear. After departing lax on an IFR part 91 flight, just returning into service from maintenance, we were cleared on runway heading (runway 25R) to maintain 2000 ft and then cleared to 3000 ft before reaching 2000 ft. ATC then cleared us to 10000 ft with traffic at our 1 O'clock position off the north runways, looked to be a B757. After passing somewhere through 5500 ft, ATC asked us to maintain 9000 ft. Radio communications at the time were moderate and sometime very soon socal asked us to contact ZLA on frequency 135.50. After we leveled off we were then cleared to 10000 ft and leveled off there. ATC then cleared us direct vtu direct kwang intersection and maintain 11000 ft, at which time my copilot read back, 'cleared direct vtu direct kwang 11000 ft.' after reaching 11000 ft, ATC called, aircraft X say altitude. My copilot responded, level 11000 ft. ATC then responded back and said we were cleared to maintain 10000 ft, descend immediately to 10000 ft. We immediately descended to 10000 ft. Nothing further was discussed by ATC regarding this apparent deviation. No other measures were taken by us or any other aircraft to my knowledge. My copilot and I both heard our clearance to maintain 11000 ft with a readback and both felt very confident that we heard the clearance correctly.
Original NASA ASRS Text
Title: A LEAR 35 FLC WAS RECLRED TO AN ALT THEN DIRECTED TO DSND TO THE PREVIOUS ALT BY ZLA.
Narrative: IT WAS A NORMAL DAY, VISIBILITY WAS MORE THAN 10 MI AND CLR. AFTER DEPARTING LAX ON AN IFR PART 91 FLT, JUST RETURNING INTO SVC FROM MAINT, WE WERE CLRED ON RWY HDG (RWY 25R) TO MAINTAIN 2000 FT AND THEN CLRED TO 3000 FT BEFORE REACHING 2000 FT. ATC THEN CLRED US TO 10000 FT WITH TFC AT OUR 1 O'CLOCK POS OFF THE N RWYS, LOOKED TO BE A B757. AFTER PASSING SOMEWHERE THROUGH 5500 FT, ATC ASKED US TO MAINTAIN 9000 FT. RADIO COMS AT THE TIME WERE MODERATE AND SOMETIME VERY SOON SOCAL ASKED US TO CONTACT ZLA ON FREQ 135.50. AFTER WE LEVELED OFF WE WERE THEN CLRED TO 10000 FT AND LEVELED OFF THERE. ATC THEN CLRED US DIRECT VTU DIRECT KWANG INTXN AND MAINTAIN 11000 FT, AT WHICH TIME MY COPLT READ BACK, 'CLRED DIRECT VTU DIRECT KWANG 11000 FT.' AFTER REACHING 11000 FT, ATC CALLED, ACFT X SAY ALT. MY COPLT RESPONDED, LEVEL 11000 FT. ATC THEN RESPONDED BACK AND SAID WE WERE CLRED TO MAINTAIN 10000 FT, DSND IMMEDIATELY TO 10000 FT. WE IMMEDIATELY DSNDED TO 10000 FT. NOTHING FURTHER WAS DISCUSSED BY ATC REGARDING THIS APPARENT DEV. NO OTHER MEASURES WERE TAKEN BY US OR ANY OTHER ACFT TO MY KNOWLEDGE. MY COPLT AND I BOTH HEARD OUR CLRNC TO MAINTAIN 11000 FT WITH A READBACK AND BOTH FELT VERY CONFIDENT THAT WE HEARD THE CLRNC CORRECTLY.
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.