ZDV ARTCC IS UNSURE OF DIRECTION OF TURN FOR AN ACFT HOLDING NEARBY PASSING TFC. CTLR IS CONCERNED ABOUT LOSS OF SEPARATION.

Date: 1999-03

Anomalies: conflict-airborne-conflict|other-unspecified

Synopsis

ZDV ARTCC IS UNSURE OF DIRECTION OF TURN FOR AN ACFT HOLDING NEARBY PASSING TFC. CTLR IS CONCERNED ABOUT LOSS OF SEPARATION.

Narrative

APCHING RLG; ZDV TOLD US TO HOLD W. WE PROGRAMMED FMC AND CONCLUDED THE AUTOMATIC SYS WOULD PROBABLY MAKE A TEARDROP ENTRY. JUST PRIOR TO ENTRY; WE WERE TOLD TO DSND TO 16000 FT. ENTERED HOLD AND ACFT TURNED L TO APPROX 220 DEGS; TEARDROP ENTRY AND PROCEEDED OUTBOUND; DSNDING. APPROX 45 SECONDS LATER; ATC BECAME EXTREMELY EXCITED AND UPSET. 'ACR X; WHAT IS YOUR HDG? WHERE ARE YOU GOING? WHAT ARE YOU DOING?...' IN A HIGHLY EXCITABLE AND AGITATED VOICE. WE REPLIED WE WERE HDG 220 DEGS; PERFORMING A TEARDROP HOLDING ENTRY. ATC TOLD US TO TURN R IMMEDIATELY. WE COMPLIED WITH AN AUTOMATED HDG SELECT STANDARD TURN. ATC ORDERED US TO DSND IMMEDIATELY THROUGH FL220; TURN R IMMEDIATELY (HIGH PERFORMANCE AND EXCITABLE VOICE). I DISCONNECTED AUTOPLT; BANKED TO APPROX 45 DEGS; EXTENDED SPD BRAKES; AND BEGAN RAPID DSCNT AS ORDERED. ATC SPOKE TO ACR Y ABOUT TFC CONFLICT AND ACR Y REPLIED HE HAD US IN SIGHT. WE NOTED A TA ALERT FOR 'TFC.' NO RA RECEIVED. AS 'CRISIS' ABATED; WE RESUMED AUTOFLT INBOUND TO RLG. ATC ASKED ME TO EXPLAIN AGAIN WHAT WE WERE DOING. I COMPLIED. PROB AROSE: ATC UNFAMILIAR WITH TEARDROP HOLDING ENTRY; EXPECTED TO SEE A PARALLEL ENTRY. ANOTHER ACFT WAS TRAVERSING THROUGH OR NEAR OUR PROTECTED HOLDING SPACE. ATC; NOT BEING FAMILIAR WITH OUR ENTRY AND NOT KNOWING OUR INTENTIONS; REACTED VIGOROUSLY TO AVOID A POTENTIAL TFC CONFLICT. WE EXCEEDED 'NORMAL' FLT PARAMETERS TO COMPLY WITH ATC'S EXCITABLE STATE. ATC PERCEPTION: WE WERE LOST; SCREWED UP; AND DOING SOMETHING WRONG. CREW PERCEPTION: STANDARD HOLDING TEARDROP ENTRY AS BRIEFED; AND LATER DOUBLECHKED IN COMPUTER FOR PROPER SETUP. CORRECTIVE ACTION: INSURE ATC CTLR AT ZDV IS INSTRUCTED AND BRIEFED ON TEARDROP HOLDING ENTRIES. SUBSEQUENT CLRNC FOR APCH AFTER PASSING RLG; EXCEEDED AUTOFLT CAPABILITIES; REQUIRING CAPT TO TAKE OVER MANUALLY IN ORDER TO REMAIN WITHIN PROPER AIRSPACE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: FLC HAD CHKED WITH EACH OTHER WHAT THE PROPER PROC WOULD BE TO ENTER THE HOLDING PATTERN AND CONFIRMED IT WITH WHAT THE COMPUTER INDICATED THAT IT SHOULD BE. FLC ALSO KNEW THAT FROM THEIR DIRECTION OF ENTRY; EITHER METHOD OF ENTRY; TEARDROP OR PARALLEL; WAS ACCEPTABLE. WHEN CTLR STARTED TO ANXIOUSLY INQUIRE WHY THEY WERE FLYING IN THE DIRECTION THEY WERE; THE FLC BECAME CONVINCED THAT THE CTLR WAS NOT FAMILIAR WITH HOLDING ENTRY PROCS. FLC WAS CONFIDENT THAT DIRECTION OF HOLDING WAS PROPER; THE CTLR NEVER CHALLENGED THAT; ONLY THE DIRECTION OF TURN DURING THE INITIAL ENTRY WAS CHALLENGED. THEY ASSUMED THE CTLR KNEW HOLDING ENTRY RULES; THEREFORE; THE CTLR WAS CHALLENGING AN AREA WITH WHICH HE WAS NOT FAMILIAR. EVIDENTLY THE CTLR WAS CONCERNED WITH THE PROX OF ANOTHER PASSING ACR; WHEN THE RPTR'S ACFT DID NOT TURN IN THE ANTICIPATED DIRECTION THE CTLR THOUGHT IT SHOULD TURN.

Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.