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Crew allegedly misinterped a descent clearance causing a planned leveloff at wrong altitude.
| Attributes | |
| ACN | 491410 |
| Time | |
| Date | 200011 |
| Day | Fri |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | navaid : fak.vortac |
| State Reference | VA |
| Altitude | msl bound lower : 21000 msl bound upper : 23000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other Other other vortac |
| Route In Use | enroute airway : j51.airway |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zdc.artcc |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | descent : vacating altitude |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : commercial pilot : flight engineer pilot : instrument pilot : multi engine pilot : cfi |
| Experience | flight time last 90 days : 140 flight time total : 3100 flight time type : 215 |
| ASRS Report | 491410 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance none taken : anomaly accepted none taken : detected after the fact |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
I was the first officer and PF on air carrier flight XXX from atl to iad, level at FL230 on J51 between crewe and fak. ATC cleared us to descend to FL200. I entered FL200 in the altitude window of the MCP and initiated a 1000 FPM descent with the autoplt on. The captain (PNF) read back the clearance as 'flight level two zero zero' and pointed at the MCP altitude window to confirm the correct setting, per company procedures. I stopped the descent and the captain questioned ATC to confirm our altitude assignment. ATC then amended the clearance as 'maintain FL210.' I entered FL210 in the altitude window of the MCP and the captain read back 'flight level two one zero.' the autoplt captured and leveled off at FL210. ATC then cleared us to 'turn right heading 090 degrees for traffic.' I turned to the new heading and the captain read back the clearance. The captain questioned ATC about the altitude confusion and ATC said he believed we were originally cleared to FL220, but he would have to pull the tapes to be sure. He also said the other aircraft was 'hurried down' and there were no separation problems. He then cleared us to new heading 360 degrees to rejoin our flight planned route. There were no TCASII alerts in our aircraft. The captain and I discussed the sequence of events and we both believe the original clearance was for FL200 and ATC made a mistake. ATC may have intended to say FL220, but did not say it and did not correct the captain when he read back FL200. I believe that ATC should be required to listen for and hear a correct readback of altitude clrncs. Pilots are required to read them back for a reason.
Original NASA ASRS Text
Title: CREW ALLEGEDLY MISINTERPED A DSCNT CLRNC CAUSING A PLANNED LEVELOFF AT WRONG ALT.
Narrative: I WAS THE FO AND PF ON ACR FLT XXX FROM ATL TO IAD, LEVEL AT FL230 ON J51 BTWN CREWE AND FAK. ATC CLRED US TO DSND TO FL200. I ENTERED FL200 IN THE ALT WINDOW OF THE MCP AND INITIATED A 1000 FPM DSCNT WITH THE AUTOPLT ON. THE CAPT (PNF) READ BACK THE CLRNC AS 'FLT LEVEL TWO ZERO ZERO' AND POINTED AT THE MCP ALT WINDOW TO CONFIRM THE CORRECT SETTING, PER COMPANY PROCS. I STOPPED THE DSCNT AND THE CAPT QUESTIONED ATC TO CONFIRM OUR ALT ASSIGNMENT. ATC THEN AMENDED THE CLRNC AS 'MAINTAIN FL210.' I ENTERED FL210 IN THE ALT WINDOW OF THE MCP AND THE CAPT READ BACK 'FLT LEVEL TWO ONE ZERO.' THE AUTOPLT CAPTURED AND LEVELED OFF AT FL210. ATC THEN CLRED US TO 'TURN R HDG 090 DEGS FOR TFC.' I TURNED TO THE NEW HDG AND THE CAPT READ BACK THE CLRNC. THE CAPT QUESTIONED ATC ABOUT THE ALT CONFUSION AND ATC SAID HE BELIEVED WE WERE ORIGINALLY CLRED TO FL220, BUT HE WOULD HAVE TO PULL THE TAPES TO BE SURE. HE ALSO SAID THE OTHER ACFT WAS 'HURRIED DOWN' AND THERE WERE NO SEPARATION PROBS. HE THEN CLRED US TO NEW HDG 360 DEGS TO REJOIN OUR FLT PLANNED RTE. THERE WERE NO TCASII ALERTS IN OUR ACFT. THE CAPT AND I DISCUSSED THE SEQUENCE OF EVENTS AND WE BOTH BELIEVE THE ORIGINAL CLRNC WAS FOR FL200 AND ATC MADE A MISTAKE. ATC MAY HAVE INTENDED TO SAY FL220, BUT DID NOT SAY IT AND DID NOT CORRECT THE CAPT WHEN HE READ BACK FL200. I BELIEVE THAT ATC SHOULD BE REQUIRED TO LISTEN FOR AND HEAR A CORRECT READBACK OF ALT CLRNCS. PLTS ARE REQUIRED TO READ THEM BACK FOR A REASON.
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.