Cessna U206 and Piper PA-31-350 mid-air collision near Port Alsworth, Alaska, July 10, 2011
On July 10, 2011 at about 9:15 pm local time, 2 aircraft, Cessna U206 (N2186F) and Piper PA-31-350 (N76RA), were involved in a mid-air collision near Port Alsworth, Alaska. No one was hurt; 13 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot’s failure to see and avoid the approaching airplane, which did not have any forward-facing lights.
The pilot’s failure to see and avoid the approaching airplane. Contributing to the accident was that the pilot’s failure to listen to radio position reports from the other airplane on the common traffic advisory frequency and the absence of any forward-facing lights on his airplane.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 10, 2011 · about 9:15 pm local time
- Place
- Port Alsworth, Alaska · map
- Type
- Accident · mid-air collision
- Injuries
- No one was hurt; 13 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Cessna U206 · all U206s on the register
- Registration
- N2186F · registry record · serial U2060386
- Damage
- Minor damage
- Flight
- Personal flight · general aviation rules (Part 91)
- Aircraft 2
- Piper PA-31-350 · all PA-31-350s on the register
- Registration
- N76RA · registry record · serial 31-7752089
- Damage
- Substantial damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative for the Cessna U206 final · quoted from the NTSB record
Two airplanes, a Cessna and a Piper, collided midair in a mountain pass while traveling in opposite directions. The pass is a river valley, about 1/2-mile wide, with the floor about 1,000 feet mean sea level (msl), between mountains in excess of 5,000 feet msl. Neither pilot saw the other airplane in time to take evasive action. Both airplanes landed safely after the collision. The airplanes were operating in visual flight rules meteorological conditions, in uncontrolled airspace at about 2,300 feet msl, without any air traffic control services. The westbound Cessna sustained minor damage to its left float and the eastbound Piper sustained substantial damage to its vertical stabilizer and rudder. The Cessna pilot reported that he was monitoring the common traffic advisory frequency (CTAF) for the pass and making position reports. He saw the opposing airplane pass under his left front and heard a loud “thump.” The Cessna was equipped with wingtip- and tail-mounted strobe anticollision lights, which were operating at the time of collision. The Piper pilot reported that when he spotted the Cessna floatplane he did not have time to take evasive action. He was not monitoring the CTAF, and the airplane he was flying had no anticollision wingtip strobes or any forward-facing lights. A local Federal Aviation Administration publication contains a graphic representation of the pass, and includes remote communications outlets, weather cameras, reference points, and a CTAF for the pass.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The NTSB's narrative for the Piper PA-31-350 final · quoted from the NTSB record
Two airplanes, a Cessna and a Piper, collided midair in a mountain pass while traveling in opposite directions. The pass is a river valley, about 1/2-mile wide, with the floor about 1,000 feet mean sea level (msl), between mountains in excess of 5,000 feet msl. Neither pilot saw the other airplane in time to take evasive action. Both airplanes landed safely after the collision. The airplanes were operating in visual flight rules meteorological conditions, in uncontrolled airspace at about 2,300 feet msl, without any air traffic control services. The westbound Cessna sustained minor damage to its left float and the eastbound Piper sustained substantial damage to its vertical stabilizer and rudder. The Cessna pilot reported that he was monitoring the common traffic advisory frequency (CTAF) for the pass and making position reports. He saw the opposing airplane pass under his left front and heard a loud “thump.” The Cessna was equipped with wingtip- and tail-mounted strobe anticollision lights, which were operating at the time of collision. The Piper pilot reported that when he spotted the Cessna floatplane he did not have time to take evasive action. He was not monitoring the CTAF, and the airplane he was flying had no anticollision wingtip strobes or any forward-facing lights. A local Federal Aviation Administration publication contains a graphic representation of the pass, and includes remote communications outlets, weather cameras, reference points, and a CTAF for the pass.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record for the Cessna U206 from the NTSB's investigation tables, in plain English
What happened, in order
- Midair collision during enroute (cruise) defining event
The NTSB's findings
- Environmental issues › Operating environment › Air traffic/operating proc › Traffic congestion › Contributed to outcome
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane
- Flight time: 29,000 hours in all; 1,500 in this make and model; 90 in the last 90 days; 60 in the last 30 days; 27,500 as pilot in command
- Last flight review: May 16, 2011
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Last inspection: annual inspection
- Maximum gross weight: 3,300 lb
- Seats: 6
- Landing gear: retractable
- Engine: Cont Motor IO 520 SERIES (piston); 0 hours total
The flight
- Departed from: LHD Anchorage AK at 3:10 pm
- Destination: Brooks Camp AK
- Flight plan: VFR
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: overcast at 4,000 ft; clear
- Temperature: 50°F (10°C), dew point 0°F (-18°C)
- Altimeter: 30.11 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 3 |
The factual record for the Piper PA-31-350 from the NTSB's investigation tables, in plain English
What happened, in order
- Midair collision during enroute (cruise) defining event
The NTSB's findings
- factor Aircraft › Aircraft systems › Lighting system › Exterior lighting › Design
- factor Personnel issues › Task performance › Communication (personnel) › Lack of communication › Pilot
- Environmental issues › Operating environment › Air traffic/operating proc › Traffic congestion › Contributed to outcome
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane
- Flight time: 19,719 hours in all; 6,500 in this make and model; 189 in the last 90 days; 89 in the last 30 days; 19,719 as pilot in command
- Last flight review: March 29, 2011
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 12,311 hours
- Last inspection: approved inspection programme, June 27, 2011
- Maximum gross weight: 7,368 lb
- Seats: 8
- Landing gear: retractable
- Engine 1: Lycoming TIO-540 SER (piston); 0 hours total
- Engine 2: Lycoming TIO-540 SER (piston); 0 hours total
- Operator: Lake Clark Air INC
The flight
- Departed from: 9K2 Kokhanok AK at 3:54 pm
- Destination: MRI Anchorage AK
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 8 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.