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An air carrier DC9 flight crew apparently misinterped their clearance as 10000 ft versus 11000 ft. The flight crew claims that the controller used bad technique when transmitting the clearance.
| Attributes | |
| ACN | 383620 |
| Time | |
| Date | 199710 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : byp airport : dfw |
| State Reference | TX |
| Altitude | msl bound lower : 10000 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zfw tracon : dfw |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 Undifferentiated or Other Model |
| Flight Phase | descent other |
| Route In Use | arrival other arrival star : star |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 110 flight time total : 10000 flight time type : 5000 |
| ASRS Report | 383620 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | altitude deviation : crossing restriction not met altitude deviation : overshoot non adherence : clearance non adherence : far other anomaly other |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
We were flying the byp 2 arrival into dfw. The center controller gave us a clearance to cross covie intersection at 10000 ft MSL. We read back 10000 ft at covie and continued. Even though the STAR has crossing restrs at other intxns at expect 11000 ft, I had on other flts been given 10000 ft, so I did not question it. As we descended through 11000 ft for 10000 ft the center controller handed us off to the next controller. We checked in with him as being out of 10400 ft for covie at 10000 ft. He said the previous controller should not have cleared us to 10000 ft and we were instructed to climb and maintain 11000 ft. No further comments were made and we landed in dfw normally. I believe 2 events contributed to this problem. #1 is being given a restr at an intersection that we normally are not given and has no expect clearance on the STAR. #2 the controller not using good terminology for 10000 ft or 11000 ft which is described in the aim as saying 'one zero thousand ten thousand' for example. We also contributed by not questioning the altitude as being different from the STAR. However, this complacency was due to the fact I have been given 10000 ft on this arrival before.
Original NASA ASRS Text
Title: AN ACR DC9 FLC APPARENTLY MISINTERPED THEIR CLRNC AS 10000 FT VERSUS 11000 FT. THE FLC CLAIMS THAT THE CTLR USED BAD TECHNIQUE WHEN XMITTING THE CLRNC.
Narrative: WE WERE FLYING THE BYP 2 ARR INTO DFW. THE CTR CTLR GAVE US A CLRNC TO CROSS COVIE INTXN AT 10000 FT MSL. WE READ BACK 10000 FT AT COVIE AND CONTINUED. EVEN THOUGH THE STAR HAS XING RESTRS AT OTHER INTXNS AT EXPECT 11000 FT, I HAD ON OTHER FLTS BEEN GIVEN 10000 FT, SO I DID NOT QUESTION IT. AS WE DSNDED THROUGH 11000 FT FOR 10000 FT THE CTR CTLR HANDED US OFF TO THE NEXT CTLR. WE CHKED IN WITH HIM AS BEING OUT OF 10400 FT FOR COVIE AT 10000 FT. HE SAID THE PREVIOUS CTLR SHOULD NOT HAVE CLRED US TO 10000 FT AND WE WERE INSTRUCTED TO CLB AND MAINTAIN 11000 FT. NO FURTHER COMMENTS WERE MADE AND WE LANDED IN DFW NORMALLY. I BELIEVE 2 EVENTS CONTRIBUTED TO THIS PROB. #1 IS BEING GIVEN A RESTR AT AN INTXN THAT WE NORMALLY ARE NOT GIVEN AND HAS NO EXPECT CLRNC ON THE STAR. #2 THE CTLR NOT USING GOOD TERMINOLOGY FOR 10000 FT OR 11000 FT WHICH IS DESCRIBED IN THE AIM AS SAYING 'ONE ZERO THOUSAND TEN THOUSAND' FOR EXAMPLE. WE ALSO CONTRIBUTED BY NOT QUESTIONING THE ALT AS BEING DIFFERENT FROM THE STAR. HOWEVER, THIS COMPLACENCY WAS DUE TO THE FACT I HAVE BEEN GIVEN 10000 FT ON THIS ARR BEFORE.
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.