Jnu tower controller was informed of an near midair collision between a DHC2 landing on the water la...

Narrative:

A C150 departed as I took local one. He was slow and outbound for outer point. A DHC2 called inbound for a straight in. I noticed an IFR strip for a learjet on a visual approach. He was only seven miles from the field. Much closer than he should have been without being switched to juneau tower. In addition; he was at 10000 feet. When he finally came over I was expecting a possible go around and handling an unusual situation with an IFR aircraft. At the same time the DHC2 called inbound from outer point. By the time I got back to the cessna and gave traffic on the DHC2; the cessna said he saw him and was passed him. All aircraft landed without incident upon arrival the DHC2 was rolling out in the water lane and the pilot said; 'hey tower I saw that cessna as he passed my windshield.' the cessna was not equipped with a transponder. It was outside my class delta airspace and I was handling an unusual situation with an IFR learjet. The pilot called and complained on the traffic call and a newly certified controller in charge took the call. The controller in charge mistakenly checked significant and filed as an near midair collision instead of public inquiry. It was two VFR airplanes outside my airspace and I was giving priority handling to an IFR aircraft.

Original NASA ASRS Text

Title: JNU Tower Controller was informed of an NMAC between a DHC2 landing on the water lane and a C150 that had departed opposite direction a few minutes earlier from the paved runway. Both aircraft were VFR and the C150 was not transponder equipped.

Narrative: A C150 departed as I took Local one. He was slow and outbound for outer point. A DHC2 called inbound for a straight in. I noticed an IFR strip for a Learjet on a Visual approach. He was only seven miles from the field. Much closer than he should have been without being switched to Juneau tower. In addition; he was at 10000 feet. When he finally came over I was expecting a possible go around and handling an unusual situation with an IFR aircraft. At the same time the DHC2 called inbound from outer point. By the time I got back to the Cessna and gave traffic on the DHC2; the Cessna said he saw him and was passed him. All aircraft landed without incident upon arrival the DHC2 was rolling out in the water lane and the pilot said; 'hey tower I saw that Cessna as he passed my windshield.' The Cessna was not equipped with a transponder. It was outside my class Delta airspace and I was handling an unusual situation with an IFR Learjet. The pilot called and complained on the traffic call and a newly certified CIC took the call. The CIC mistakenly checked significant and filed as an NMAC instead of public inquiry. It was two VFR airplanes outside my airspace and I was giving priority handling to an IFR aircraft.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1358838
Time
Date	201605
Local Time Of Day	0001-0600
Place
Locale Reference	JNU.Airport
State Reference	AK
Aircraft 1
Make Model Name	Beaver DHC-2
Flight Phase	Descent
Route In Use	None
Flight Plan	VFR
Aircraft 2
Make Model Name	Cessna 150
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	None
Flight Plan	VFR
Person 1
Function	Local
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 4.0
Events
Anomaly	ATC Issue All Types Conflict NMAC Deviation - Procedural Other / Unknown

Jnu tower controller was informed of an near midair collision between a DHC2 landing on the water lane and a C150 that had departed opposite direction a few minutes earlier from the paved runway. Both aircraft were VFR and the C150 was not transponder equipped.