|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : hln|
|Altitude||msl bound lower : 4600|
msl bound upper : 4600
|Controlling Facilities||tower : hln|
|Operator||general aviation : instructional|
|Make Model Name||Small Aircraft, High Wing, 1 Eng, Fixed Gear|
|Operator||common carrier : air carrier|
|Make Model Name||Medium Large Transport, Low Wing, 2 Turbojet Eng|
|Flight Phase||descent : approach|
|Function||flight crew : single pilot|
|Qualification||pilot : student|
|Experience||flight time last 90 days : 20|
flight time total : 20
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Anomaly||conflict : nmac|
|Independent Detector||other controllera|
|Resolutory Action||flight crew : took evasive action|
|Consequence||faa : reviewed incident with flight crew|
|Miss Distance||horizontal : 300|
vertical : 0
I was flying left pattern on the downwind leg when I was advised by the tower that an, 'medium large transport was turning 1 mi right base for 27.' I acknowledged reception of the transmission and continued my downwind leg. I was just west of the stacks in east helena when the tower told me to, 'turn base at my discretion.' no mention was made if traffic was in sight. I had not seen the medium large transport, but was of the opinion it must not be a factor any longer. I advised the tower I was turning base. As I was ready to turn final, the tower asked if I had traffic in sight. I replied, 'negative.' tower told me to, 'make right turn now.' I did and saw the medium large transport pass immediately to my right. We were at approximately the same altitude and about 300' apart. I spoke to the tower controller by phone shortly after landing. She said she thought the medium large transport and I were passing each other when she instructed me to turn base at my discretion.
Original NASA ASRS Text
Title: TRAFFIC ADVISORY GIVEN BUT THE ACFT WAS NOT SIGHTED. NMAC OCCURRED WHEN TWR REQUESTED THE REPORTER TURN BASE AT PLT'S DISCRETION.
Narrative: I WAS FLYING LEFT PATTERN ON THE DOWNWIND LEG WHEN I WAS ADVISED BY THE TWR THAT AN, 'MLG WAS TURNING 1 MI RIGHT BASE FOR 27.' I ACKNOWLEDGED RECEPTION OF THE XMISSION AND CONTINUED MY DOWNWIND LEG. I WAS JUST W OF THE STACKS IN E HELENA WHEN THE TWR TOLD ME TO, 'TURN BASE AT MY DISCRETION.' NO MENTION WAS MADE IF TFC WAS IN SIGHT. I HAD NOT SEEN THE MLG, BUT WAS OF THE OPINION IT MUST NOT BE A FACTOR ANY LONGER. I ADVISED THE TWR I WAS TURNING BASE. AS I WAS READY TO TURN FINAL, THE TWR ASKED IF I HAD TFC IN SIGHT. I REPLIED, 'NEGATIVE.' TWR TOLD ME TO, 'MAKE RIGHT TURN NOW.' I DID AND SAW THE MLG PASS IMMEDIATELY TO MY RIGHT. WE WERE AT APPROX THE SAME ALT AND ABOUT 300' APART. I SPOKE TO THE TWR CTLR BY PHONE SHORTLY AFTER LNDG. SHE SAID SHE THOUGHT THE MLG AND I WERE PASSING EACH OTHER WHEN SHE INSTRUCTED ME TO TURN BASE AT MY DISCRETION.
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.