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Accidents · NTSB WPR20LA304 · Final report

Cessna 172 accident near Seeley Lake, Montana, September 13, 2020

On September 13, 2020 at about 3:52 am local time, a 1966 Cessna 172, registered N3720R, was substantially damaged in an accident during approach near Seeley Lake, Montana (Seeley Lake airport). It was a personal flight under general aviation rules (Part 91). 2 people were killed and 1 person was seriously injured. The weather was instrument conditions (cloud, fog or low visibility).

The NTSB's probable cause their words, unchanged

The noninstrument-rated pilot’s encounter with instrument meteorological conditions during a night visual approach due to wildfire smoke, which resulted in controlled flight into terrain.

Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.

What the record shows

Date
September 13, 2020 · about 3:52 am local time
Place
Seeley Lake, Montana · Seeley Lake · map
Type
Accident
Injuries
2 people were killed and 1 person was seriously injured.
Weather
instrument conditions (cloud, fog or low visibility)
Aircraft
Cessna 172 H, built 1966 · all 172s on the register
Registration
N3720R · no longer on the register · serial 17255520
Damage
Substantial damage
Flight
Personal flight · general aviation rules (Part 91)

The NTSB's narrative final · quoted from the NTSB record

The airplane with a noninstrument-rated pilot and two passengers onboard was on a night cross-country flight. A witnesses heard the airplane approach the destination airport from the south and continue past the airport to the north until he could no longer hear it. Local law enforcement personnel began a search for the airplane after witnesses reported hearing a crash, and they located the accident site early the next morning about 3/4 miles north of the airport. The airplane impacted the top of about 75-ft-tall trees and traveled about 365 ft through the treetops on a heading of about 152° before coming to rest. The distance the airplane traveled through the trees was consistent with controlled flight into terrain, and the heading was consistent with a final approach to the airport’s south runway. Postaccident examination of the airframe and engine revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. The damage to the propeller was consistent with it rotating under power at impact. A review of weather near the accident site revealed that many wildfires were occurring in the Pacific Northwest at the accident time. A westerly wind carried the smoke from these fires to the area of the accident site. The accident occurred after sunset and with an inversion over the accident site, which trapped and concentrated smoke between the ground and 1,000 ft above ground level. Visibility likely decreased to instrument flight rules levels due to the smoke, and the limited visibility was compounded by the dark night light condition. The first law enforcement officer at the accident site stated that there was haze, and that the visibility was between 1 to 3 miles. It is likely the airplane encountered instrument meteorological conditions (IMC) during the visual approach to the airport, which resulted in the pilot losing visual contact with the ground. The IMC weather conditions, the airplane’s path through the trees on runway heading, and the evidence of normal engine operation were all consistent with the noninstrument-rated pilot’s-controlled flight into terrain during a night visual approach.

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 from the NTSB's investigation tables, in plain English

What happened, in order

  1. VFR encounter with IMC during approach defining event
  2. Controlled flight into terrain or object (CFIT) during approach

The NTSB's findings

  • Environmental issues › Conditions/weather/phenomena › Ceiling/visibility/precip › Haze/smoke › Effect on personnel
  • Environmental issues › Physical environment › Object/animal/substance › Tree(s) › Contributed to outcome
  • Environmental issues › Conditions/weather/phenomena › Ceiling/visibility/precip › Below VFR minima › Effect on personnel
  • Personnel issues › Experience/knowledge › Experience/qualifications › Total instrument experience › Pilot

Pilot

  • Certificate: private
  • Ratings: single-engine land
  • Flight time: 569 hours in all; 336 in this make and model; 33 in the last 90 days; 14 in the last 30 days
  • Last flight review: July 23, 2019
  • Medical certificate: Class 3 (with waivers/limitations)
  • Seat: left
  • Injury: fatal

Passenger

  • Seat: rgt
  • Injury: serious injuries

Passenger

  • Seat: rear
  • Injury: fatal

The aircraft

  • Airframe total time: 5,712.2 hours
  • Last inspection: annual inspection, November 1, 2019
  • Maximum gross weight: 2,300 lb
  • Seats: 4
  • Landing gear: fixed
  • Engine: Lycoming O-360-A1A (piston); 3,417 hours total

The flight

  • Flight plan: none

Weather at the time

  • Light: night
  • Visibility: 6 statute miles
  • Sky: clear
  • Temperature: 61°F (16°C), dew point 37°F (3°C)
  • Altimeter: 29.98 inHg
  • Observation at 3:53 pm from KMSO, 31 miles away

Injuries

FatalSeriousMinorNone
Flight crew1
Passengers11

Documents from the investigation the NTSB's docket: the evidence folder behind the report

18 documents, released by the NTSB on October 4, 2022. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.

The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.

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.