Narrative:

Sun (a beautiful day), 8/88, about XA00 local time. Small transport was cleared from toronto island to buf at 3500'. Toronto control turned us over to buf approach. Transponder and altimeter settings were set and we were idented. I had a course set up to take small transport to the OM for right turn into runway 23 at buf. Approach advised we would be following an medium large transport. The thought that small transport would catch up to medium large transport didn't seem a possibility. Shortly after that we were cleared to a heading of 140 degrees and queried to see if the airport was in sight at 1-2 O'clock. That was verified and I requested descent to 2000'. That was acknowledged by 'descend at pilot's discretion.' based on the query of seeing the airport, and the 'descend pilot discretion,' triggered the thought we were cleared visually to the airport. While setting #2 communication to tower frequency, and selecting the other communication back to approach, we were descending on a heading to make a right turn with a short base. I could see the medium large transport on final and realized we were too close to follow. The radio mixup had disconnected us from approach and to expedite immediate communication I called the tower and requested a left 360 degree to get re-established on final. That was granted and small transport was cleared to land. Ground control asked me to call approach when I arrived at the terminal phone. This I did and explained the radio mix-up in the cockpit. The controller told his side of the story which I understood. Two things went wrong: the understanding by the pilot of what he thought approach intended 'descend at pilot's discretion,' plus the fumbling of radio selectors, put small transport where approach had not intended it to be. Fortunately the visibility was excellent and no 2 aircraft tried to occupy the same airspace. After the conversation and explanation to the controller, I suspect my sins had been cleaned. I don't recall an addendum to the descend at pilot discretion, stating small transport was to maintain the assigned heading, which would have been more definitive. On the other hand, a pilot should not assume, he should know by specific information or ask! After almost 50 yrs of this, I know flight is surrounded by booby traps. It behooves all of us in the circuit to speak and to listen as though our lives depend on it--they do.

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Original NASA ASRS Text

Title: GA-SMT DEVIATED FROM ASSIGNED HEADING AND HAD TO REQUEST 360 DEGREE TURN TO AVOID OVERTAKING ACR-MLG AHEAD ON APCH.

Narrative: SUN (A BEAUTIFUL DAY), 8/88, ABOUT XA00 LCL TIME. SMT WAS CLRED FROM TORONTO ISLAND TO BUF AT 3500'. TORONTO CTL TURNED US OVER TO BUF APCH. TRANSPONDER AND ALTIMETER SETTINGS WERE SET AND WE WERE IDENTED. I HAD A COURSE SET UP TO TAKE SMT TO THE OM FOR RIGHT TURN INTO RWY 23 AT BUF. APCH ADVISED WE WOULD BE FOLLOWING AN MLG. THE THOUGHT THAT SMT WOULD CATCH UP TO MLG DIDN'T SEEM A POSSIBILITY. SHORTLY AFTER THAT WE WERE CLRED TO A HDG OF 140 DEGS AND QUERIED TO SEE IF THE ARPT WAS IN SIGHT AT 1-2 O'CLOCK. THAT WAS VERIFIED AND I REQUESTED DSCNT TO 2000'. THAT WAS ACKNOWLEDGED BY 'DSND AT PLT'S DISCRETION.' BASED ON THE QUERY OF SEEING THE ARPT, AND THE 'DSND PLT DISCRETION,' TRIGGERED THE THOUGHT WE WERE CLRED VISUALLY TO THE ARPT. WHILE SETTING #2 COM TO TWR FREQ, AND SELECTING THE OTHER COM BACK TO APCH, WE WERE DSNDING ON A HDG TO MAKE A RIGHT TURN WITH A SHORT BASE. I COULD SEE THE MLG ON FINAL AND REALIZED WE WERE TOO CLOSE TO FOLLOW. THE RADIO MIXUP HAD DISCONNECTED US FROM APCH AND TO EXPEDITE IMMEDIATE COM I CALLED THE TWR AND REQUESTED A LEFT 360 DEG TO GET RE-ESTABLISHED ON FINAL. THAT WAS GRANTED AND SMT WAS CLRED TO LAND. GND CTL ASKED ME TO CALL APCH WHEN I ARRIVED AT THE TERMINAL PHONE. THIS I DID AND EXPLAINED THE RADIO MIX-UP IN THE COCKPIT. THE CTLR TOLD HIS SIDE OF THE STORY WHICH I UNDERSTOOD. TWO THINGS WENT WRONG: THE UNDERSTANDING BY THE PLT OF WHAT HE THOUGHT APCH INTENDED 'DSND AT PLT'S DISCRETION,' PLUS THE FUMBLING OF RADIO SELECTORS, PUT SMT WHERE APCH HAD NOT INTENDED IT TO BE. FORTUNATELY THE VIS WAS EXCELLENT AND NO 2 ACFT TRIED TO OCCUPY THE SAME AIRSPACE. AFTER THE CONVERSATION AND EXPLANATION TO THE CTLR, I SUSPECT MY SINS HAD BEEN CLEANED. I DON'T RECALL AN ADDENDUM TO THE DSND AT PLT DISCRETION, STATING SMT WAS TO MAINTAIN THE ASSIGNED HDG, WHICH WOULD HAVE BEEN MORE DEFINITIVE. ON THE OTHER HAND, A PLT SHOULD NOT ASSUME, HE SHOULD KNOW BY SPECIFIC INFO OR ASK! AFTER ALMOST 50 YRS OF THIS, I KNOW FLT IS SURROUNDED BY BOOBY TRAPS. IT BEHOOVES ALL OF US IN THE CIRCUIT TO SPEAK AND TO LISTEN AS THOUGH OUR LIVES DEPEND ON IT--THEY DO.

Data retrieved from NASA's ASRS site as of August 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.