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Potential conflict ensues as a cpr flight crew leaves their assigned altitude during a clearance interpretation problem with controller at ZOA, ca.
| Attributes | |
| ACN | 548836 |
| Time | |
| Date | 200205 |
| Day | Fri |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : mry.airport |
| State Reference | CA |
| Altitude | msl bound lower : 29000 msl bound upper : 31000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zoa.artcc |
| Operator | general aviation : corporate |
| Make Model Name | Citation X |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise : level descent : intermediate altitude |
| Route In Use | departure : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zoa.artcc |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | cruise : level |
| Person 1 | |
| Affiliation | company : corporate |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : cfi pilot : instrument pilot : multi engine pilot : commercial |
| Experience | flight time last 90 days : 80 flight time total : 10000 flight time type : 400 |
| ASRS Report | 548836 |
| Person 2 | |
| Affiliation | company : corporate |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 100 flight time total : 8000 flight time type : 1200 |
| ASRS Report | 548637 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued alert controller : issued new clearance flight crew : returned to assigned altitude flight crew : took evasive action |
| Consequence | faa : reviewed incident with flight crew |
| Miss Distance | vertical : 1700 |
| Supplementary | |
| Problem Areas | Environmental Factor ATC Human Performance Airspace Structure Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
Descending en route/transitioning to approach phase into mry. ZOA working us on flight plan, then vectors, then direct to another intersection. Contributing factors: turns, getting ATIS, multiple en route (clrncs) with multiple controllers. Controllers busy with multiple aircraft. A normal scenario but getting changing inputs faster and faster so both crew members getting busier and becoming time constrained with inputs. We put in FL290 in response to a controller call referencing FL290 in 2 mins. PNF read back clearance and we began the descent from FL310 to FL290 at a normal rate for the small vertical distance, planning to be at FL290 within the 2 mins mentioned. At approximately 300 ft out of FL310, the controller asked if we were staying at FL310 and PNF responded no, we were descending to FL290. At this time the TCASII gave us an RA to fly up, turn right. Almost simultaneously, the controller said to climb to FL310 and turn 40 degrees to the right. I immediately disengaged the autoplt and complied with the RA and controller commands (which were in agreement and we were at FL310 in seconds on the new heading. Perception was that we were to descend to FL290 in 2 mins. While we think we heard, 'descend to FL290,' which we took action on, but was not the case. The PNF did read back the descent clearance to FL290 in 2 mins.
Original NASA ASRS Text
Title: POTENTIAL CONFLICT ENSUES AS A CPR FLC LEAVES THEIR ASSIGNED ALT DURING A CLRNC INTERP PROB WITH CTLR AT ZOA, CA.
Narrative: DSNDING ENRTE/TRANSITIONING TO APCH PHASE INTO MRY. ZOA WORKING US ON FLT PLAN, THEN VECTORS, THEN DIRECT TO ANOTHER INTXN. CONTRIBUTING FACTORS: TURNS, GETTING ATIS, MULTIPLE ENRTE (CLRNCS) WITH MULTIPLE CTLRS. CTLRS BUSY WITH MULTIPLE ACFT. A NORMAL SCENARIO BUT GETTING CHANGING INPUTS FASTER AND FASTER SO BOTH CREW MEMBERS GETTING BUSIER AND BECOMING TIME CONSTRAINED WITH INPUTS. WE PUT IN FL290 IN RESPONSE TO A CTLR CALL REFING FL290 IN 2 MINS. PNF READ BACK CLRNC AND WE BEGAN THE DSCNT FROM FL310 TO FL290 AT A NORMAL RATE FOR THE SMALL VERT DISTANCE, PLANNING TO BE AT FL290 WITHIN THE 2 MINS MENTIONED. AT APPROX 300 FT OUT OF FL310, THE CTLR ASKED IF WE WERE STAYING AT FL310 AND PNF RESPONDED NO, WE WERE DSNDING TO FL290. AT THIS TIME THE TCASII GAVE US AN RA TO FLY UP, TURN R. ALMOST SIMULTANEOUSLY, THE CTLR SAID TO CLB TO FL310 AND TURN 40 DEGS TO THE R. I IMMEDIATELY DISENGAGED THE AUTOPLT AND COMPLIED WITH THE RA AND CTLR COMMANDS (WHICH WERE IN AGREEMENT AND WE WERE AT FL310 IN SECONDS ON THE NEW HDG. PERCEPTION WAS THAT WE WERE TO DSND TO FL290 IN 2 MINS. WHILE WE THINK WE HEARD, 'DSND TO FL290,' WHICH WE TOOK ACTION ON, BUT WAS NOT THE CASE. THE PNF DID READ BACK THE DSCNT CLRNC TO FL290 IN 2 MINS.
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.