Narrative:

While descending eastbound on V319, 33 NM from yak with clearance to commence the ILS runway 11 approach, we had a near miss with a dehavilland twin otter aircraft at 11500 ft MSL. The aircraft was established eastbound on the airway to yak. The aircraft had a military paint scheme apparently from the guard at juneau, ak. An evasive descending left turn was executed to avoid hitting the twin otter. The estimated clearance of the aircraft was 2000 ft left (co-altitude) at passage. Current WX conditions were a cloud layer with tops between 11000 ft and 11500 ft MSL, overcast, civil twilight, with 30-40 NM visibility clear of clouds. Zan and juneau radio were not aware of the aircraft nor was a flight plan on file. No TCASII alert was observed by the flight crew. There was no warning of impending collision except for a visual contact at close range by the captain. This near midair collision could have been avoided if voice contact, filed flight plan or an operable IFR squawk by the twin otter had been done.

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Original NASA ASRS Text

Title: AN ACR B737-200 FLC EXPERIENCED AN NMAC WITH A DH6 WHILE ON AN AIRWAY, INBOUND TO YAK. THE B737-200 PF TOOK EVASIVE ACTION TO AVOID HITTING THE DH6 THAT WAS FLYING NEAR THE TOP OF AN OVCST CLOUD LAYER WITHOUT A FLT PLAN, OR RADIO CONTACT WITH CTR.

Narrative: WHILE DSNDING EBOUND ON V319, 33 NM FROM YAK WITH CLRNC TO COMMENCE THE ILS RWY 11 APCH, WE HAD A NEAR MISS WITH A DEHAVILLAND TWIN OTTER ACFT AT 11500 FT MSL. THE ACFT WAS ESTABLISHED EBOUND ON THE AIRWAY TO YAK. THE ACFT HAD A MIL PAINT SCHEME APPARENTLY FROM THE GUARD AT JUNEAU, AK. AN EVASIVE DSNDING L TURN WAS EXECUTED TO AVOID HITTING THE TWIN OTTER. THE ESTIMATED CLRNC OF THE ACFT WAS 2000 FT L (CO-ALT) AT PASSAGE. CURRENT WX CONDITIONS WERE A CLOUD LAYER WITH TOPS BTWN 11000 FT AND 11500 FT MSL, OVCST, CIVIL TWILIGHT, WITH 30-40 NM VISIBILITY CLR OF CLOUDS. ZAN AND JUNEAU RADIO WERE NOT AWARE OF THE ACFT NOR WAS A FLT PLAN ON FILE. NO TCASII ALERT WAS OBSERVED BY THE FLC. THERE WAS NO WARNING OF IMPENDING COLLISION EXCEPT FOR A VISUAL CONTACT AT CLOSE RANGE BY THE CAPT. THIS NMAC COULD HAVE BEEN AVOIDED IF VOICE CONTACT, FILED FLT PLAN OR AN OPERABLE IFR SQUAWK BY THE TWIN OTTER HAD BEEN DONE.

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.