Cessna 172 accident near Athol, Idaho, August 7, 2021
On August 7, 2021 at about 5:30 pm local time, a 1966 Cessna 172, registered N4110L, was substantially damaged in an accident during maneuvering near Athol, Idaho (Treeport airport). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the windshield during spin recovery for reasons that were not determined.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 7, 2021 · about 5:30 pm local time
- Place
- Athol, Idaho · Treeport · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172 G, built 1966 · all 172s on the register
- Registration
- N4110L · registry record · serial 17254179
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The flight instructor reported that before demonstrating spin recovery to the student pilot, he confirmed that the weight and balance met the requirements for the utility category. The flight instructor stated that as the spin reached the fully developed state, he began to execute the recovery procedure by reducing power to idle, ailerons remained at neutral, opposite rudder control to stop the turn, and the elevator forward. During the recovery, he noted that the airspeed did not exceed 110 mph which was 12 mph below the design maneuvering speed of 122 mph. Subsequently, the windshield shattered during the recovery process. The flight instructor immediately landed the airplane at the airport that he was maneuvering over without further incident. An examination of the airplane revealed that about half of the windshield separated. The airplane fuselage, wings and empennage were not damaged. The reason for the windshield failure was not determined.
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
- Aircraft structural failure during maneuvering defining event
The NTSB's findings
- Aircraft › Aircraft structures › Windows › windshield system › Flight compartment windows › Failure
- Not determined › Not determined › (general) › (general) › Unknown/Not determined
Flight instructor
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 1,480 hours in all; 410 in this make and model; 269 in the last 90 days; 112 in the last 30 days; 1,389 as pilot in command; 1,222 on instruments
- Last flight review: November 11, 2019
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
Pilot-Rated Passenger
- Certificate: private
- Ratings: single-engine land
- Flight time: 63 hours in all; 61 in this make and model; 63 in the last 90 days; 39 in the last 30 days; 15 as pilot in command
- Last flight review: August 6, 2021
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 3,154 hours
- Last inspection: annual inspection, October 12, 2020; 74 hours since
- Seats: 4
- Landing gear: fixed
- Engine: Cont Motor 0-300 SER (piston); 3,154 hours total
The flight
- Departed from: COE Coeur D'Alene ID at 5:15 pm
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 180° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 70°F (21°C), dew point 54°F (12°C)
- Altimeter: 20.06 inHg
- Observation at 8:56 am from KCOE, 13 miles away
Weather report (METAR): KCOE 071556Z AUTO 18007KT 10SM CLR 21/12 A2006
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
3 documents, released by the NTSB on February 10, 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.
| # | Document | What it is | |
|---|---|---|---|
| 1 | FAA Inspection Notes | PDF, 2 pages | View Download |
| 2 | Flight Instructor Statement | PDF, 1 page | View Download |
| 3 | Photo Array-courtesy of Airplane Owner | PDF, 4 pages | View Download |
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.