Altitude deviation due to communication problem between ATC and widebody transport flight crew.

Attributes
ACN	309120
Time
Date	199507
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : vqq
State Reference	FL
Altitude	msl bound lower : 29000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 22000 flight time type : 3000
ASRS Report	309120
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued new clearance
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

We were climbing from 28000 ft to 33000 ft when I heard a broken transmission with our company name and flight number. The other 2 crew members missed the radio call altogether. I told the first officer to answer the call and he did with a 'ZJX, company name and flight number.' ZJX came back and said, 'company name and flight number.' we then questioned each other and wondered what did center want? I told the first officer to call center and ask them what they had said in their last transmission. Due to the heavy radio traffic we were unable to contact center for a few moments. We finally contacted center while climbing through 32000 ft. They said they wanted us to stop the climb at 29000 ft. They then cleared us to turn left about 40 degrees and climb to 33000 ft. Center did not seem to be all that concerned. We saw no traffic visually nor was any TCASII traffic observed. It appeared that the center accepted a company name and flight number as an altitude change acknowledgement. A possible factor is the fact that we had an intermediate leveloff at 28000 ft and I let the airspeed build up. When we were then cleared to climb, because of our added speed, we had an unusually high rate of climb to 33000 ft. This unusual climb rate probably contributed to the fact that there was no conflict and center did not seem to be concerned.

Original NASA ASRS Text

Title: ALTDEV DUE TO COM PROB BTWN ATC AND WDB FLC.

Narrative: WE WERE CLBING FROM 28000 FT TO 33000 FT WHEN I HEARD A BROKEN XMISSION WITH OUR COMPANY NAME AND FLT NUMBER. THE OTHER 2 CREW MEMBERS MISSED THE RADIO CALL ALTOGETHER. I TOLD THE FO TO ANSWER THE CALL AND HE DID WITH A 'ZJX, COMPANY NAME AND FLT NUMBER.' ZJX CAME BACK AND SAID, 'COMPANY NAME AND FLT NUMBER.' WE THEN QUESTIONED EACH OTHER AND WONDERED WHAT DID CTR WANT? I TOLD THE FO TO CALL CTR AND ASK THEM WHAT THEY HAD SAID IN THEIR LAST XMISSION. DUE TO THE HVY RADIO TFC WE WERE UNABLE TO CONTACT CTR FOR A FEW MOMENTS. WE FINALLY CONTACTED CTR WHILE CLBING THROUGH 32000 FT. THEY SAID THEY WANTED US TO STOP THE CLB AT 29000 FT. THEY THEN CLRED US TO TURN L ABOUT 40 DEGS AND CLB TO 33000 FT. CTR DID NOT SEEM TO BE ALL THAT CONCERNED. WE SAW NO TFC VISUALLY NOR WAS ANY TCASII TFC OBSERVED. IT APPEARED THAT THE CTR ACCEPTED A COMPANY NAME AND FLT NUMBER AS AN ALT CHANGE ACKNOWLEDGEMENT. A POSSIBLE FACTOR IS THE FACT THAT WE HAD AN INTERMEDIATE LEVELOFF AT 28000 FT AND I LET THE AIRSPD BUILD UP. WHEN WE WERE THEN CLRED TO CLB, BECAUSE OF OUR ADDED SPD, WE HAD AN UNUSUALLY HIGH RATE OF CLB TO 33000 FT. THIS UNUSUAL CLB RATE PROBABLY CONTRIBUTED TO THE FACT THAT THERE WAS NO CONFLICT AND CTR DID NOT SEEM TO BE CONCERNED.

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.