Flight crew of a DC9 replied to the wrong call sign for another DC9 on the opposite side of the airp...

Attributes
ACN	402560
Time
Date	199805
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : stl
State Reference	MO
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	ground : holding ground other : taxi
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	ground other : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : cfi pilot : atp
Experience	flight time last 90 days : 210 flight time total : 4100 flight time type : 1050
ASRS Report	402560
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	incursion : runway non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Air carrier X was holding short of runway 30L at taxiway north. We were cleared to cross runway 30L at taxiway north for the full length of runway 30R. We read back to ATC air carrier X cleared to cross runway 30L. We cleared for traffic out the right and left windows, turned on our ice and nacelle lights and crossed runway 30L at taxiway north. Nothing was said to us to indicate we had mistaken any clearance. 2 1/2 hours later, upon our return to stl, we were advised that ATC had believed that we had crossed runway 30L at taxiway north without a clearance. We met with our chief pilot and had a conference call with the stl airport ATC facility. They stated that they had cleared air carrier Y to cross runway 30R at taxiway north for runway 30R full length. They also stated that air carrier Y was being controled on 121.90, while we were on 121.65. They said that one controller was working both frequencys and that they were in the process of splitting them. They said that in reviewing the tapes, that they heard the air carrier Y being cleared to cross runway 30R at taxiway north for runway 30R full length and that they heard part of air carrier Y readback and some other garbled talking. They went on to explain that when one controller is working both frequencys that the controller can't hear both frequencys at the same time. It was also mentioned that they were nearing a shift change. We in air carrier X honestly believed that we were given our clearance to cross runway 30L at taxiway north for the full length runway 30R. We read back our clearance to ATC, heard no objection, cleared for traffic, and proceeded as instructed. No aircraft were on final or on the runway to either the right or left. We believe that this could be prevented by having the ground controller working only one frequency so that they can hear readbacks or questioned what the 'garbled talking' was.

Original NASA ASRS Text

Title: FLC OF A DC9 REPLIED TO THE WRONG CALL SIGN FOR ANOTHER DC9 ON THE OPPOSITE SIDE OF THE ARPT RESULTING IN TAXIING ACROSS A RWY WITHOUT CLRNC. BOTH ACFT WERE TAXIING TO THE SAME RWY FOR TKOF, BUT COULD NOT SEE EACH OTHER SINCE THEY WERE ON THE OPPOSITE SIDES OF PARALLEL RWYS.

Narrative: ACR X WAS HOLDING SHORT OF RWY 30L AT TXWY N. WE WERE CLRED TO CROSS RWY 30L AT TXWY N FOR THE FULL LENGTH OF RWY 30R. WE READ BACK TO ATC ACR X CLRED TO CROSS RWY 30L. WE CLRED FOR TFC OUT THE R AND L WINDOWS, TURNED ON OUR ICE AND NACELLE LIGHTS AND CROSSED RWY 30L AT TXWY N. NOTHING WAS SAID TO US TO INDICATE WE HAD MISTAKEN ANY CLRNC. 2 1/2 HRS LATER, UPON OUR RETURN TO STL, WE WERE ADVISED THAT ATC HAD BELIEVED THAT WE HAD CROSSED RWY 30L AT TXWY N WITHOUT A CLRNC. WE MET WITH OUR CHIEF PLT AND HAD A CONFERENCE CALL WITH THE STL ARPT ATC FACILITY. THEY STATED THAT THEY HAD CLRED ACR Y TO CROSS RWY 30R AT TXWY N FOR RWY 30R FULL LENGTH. THEY ALSO STATED THAT ACR Y WAS BEING CTLED ON 121.90, WHILE WE WERE ON 121.65. THEY SAID THAT ONE CTLR WAS WORKING BOTH FREQS AND THAT THEY WERE IN THE PROCESS OF SPLITTING THEM. THEY SAID THAT IN REVIEWING THE TAPES, THAT THEY HEARD THE ACR Y BEING CLRED TO CROSS RWY 30R AT TXWY N FOR RWY 30R FULL LENGTH AND THAT THEY HEARD PART OF ACR Y READBACK AND SOME OTHER GARBLED TALKING. THEY WENT ON TO EXPLAIN THAT WHEN ONE CTLR IS WORKING BOTH FREQS THAT THE CTLR CAN'T HEAR BOTH FREQS AT THE SAME TIME. IT WAS ALSO MENTIONED THAT THEY WERE NEARING A SHIFT CHANGE. WE IN ACR X HONESTLY BELIEVED THAT WE WERE GIVEN OUR CLRNC TO CROSS RWY 30L AT TXWY N FOR THE FULL LENGTH RWY 30R. WE READ BACK OUR CLRNC TO ATC, HEARD NO OBJECTION, CLRED FOR TFC, AND PROCEEDED AS INSTRUCTED. NO ACFT WERE ON FINAL OR ON THE RWY TO EITHER THE R OR L. WE BELIEVE THAT THIS COULD BE PREVENTED BY HAVING THE GND CTLR WORKING ONLY ONE FREQ SO THAT THEY CAN HEAR READBACKS OR QUESTIONED WHAT THE 'GARBLED TALKING' WAS.

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.