Air carrier B737 flight crew accept approach clearance, not understanding issued restr and conduct a...

Attributes
ACN	408870
Time
Date	199807
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dal
State Reference	TX
Altitude	msl bound lower : 3000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dfw
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other descent : approach descent other
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 270 flight time total : 4300 flight time type : 2700
ASRS Report	408870
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Coming into love field, we (X) were cleared for the visual approach to runway 13R, following company traffic (Y) who was turning a right base in front of us. The call from the controller was (and I paraphrase) '(X) call sign, cleared the visual behind company (Y), maintain 3000 ft until (blank).' we were not totally sure where we were supposed to maintain 3000 ft. It sounded like the controller said 'maintain 3000 ft until addison,' but that did not make a whole lot of sense based on our location. As we were discussing this, and keeping an eye out for the traffic in front of us, we were told to contact tower. We went over to tower, held 3000 ft until needed for safe approach, and landed uneventfully. A couple of lessons learned: anytime a clearance is not fully understood by both crew members, query the controller. (Approach was rather busy at the time -- we should not have gone to tower until we were sure what the controller wanted.) also, we did not read back the clearance. I always try to read back all clrncs. My captain was working the radio and did not read back the clearance, probably since it was not understood. Finally, no matter how busy a controller is, a request to repeat the instructions should always be made.

Original NASA ASRS Text

Title: ACR B737 FLC ACCEPT APCH CLRNC, NOT UNDERSTANDING ISSUED RESTR AND CONDUCT APCH AS THEY INTERP THE CLRNC. FLT LANDS WITHOUT INCIDENT.

Narrative: COMING INTO LOVE FIELD, WE (X) WERE CLRED FOR THE VISUAL APCH TO RWY 13R, FOLLOWING COMPANY TFC (Y) WHO WAS TURNING A R BASE IN FRONT OF US. THE CALL FROM THE CTLR WAS (AND I PARAPHRASE) '(X) CALL SIGN, CLRED THE VISUAL BEHIND COMPANY (Y), MAINTAIN 3000 FT UNTIL (BLANK).' WE WERE NOT TOTALLY SURE WHERE WE WERE SUPPOSED TO MAINTAIN 3000 FT. IT SOUNDED LIKE THE CTLR SAID 'MAINTAIN 3000 FT UNTIL ADDISON,' BUT THAT DID NOT MAKE A WHOLE LOT OF SENSE BASED ON OUR LOCATION. AS WE WERE DISCUSSING THIS, AND KEEPING AN EYE OUT FOR THE TFC IN FRONT OF US, WE WERE TOLD TO CONTACT TWR. WE WENT OVER TO TWR, HELD 3000 FT UNTIL NEEDED FOR SAFE APCH, AND LANDED UNEVENTFULLY. A COUPLE OF LESSONS LEARNED: ANYTIME A CLRNC IS NOT FULLY UNDERSTOOD BY BOTH CREW MEMBERS, QUERY THE CTLR. (APCH WAS RATHER BUSY AT THE TIME -- WE SHOULD NOT HAVE GONE TO TWR UNTIL WE WERE SURE WHAT THE CTLR WANTED.) ALSO, WE DID NOT READ BACK THE CLRNC. I ALWAYS TRY TO READ BACK ALL CLRNCS. MY CAPT WAS WORKING THE RADIO AND DID NOT READ BACK THE CLRNC, PROBABLY SINCE IT WAS NOT UNDERSTOOD. FINALLY, NO MATTER HOW BUSY A CTLR IS, A REQUEST TO REPEAT THE INSTRUCTIONS SHOULD ALWAYS BE MADE.

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.

Air carrier B737 flight crew accept approach clearance, not understanding issued restr and conduct approach as they interpretation the clearance. Flight lands without incident.