Diamond DA 40 accident near Benson, Arizona, August 20, 2020
On August 20, 2020 at about 4:50 am local time, a 2004 Diamond DA 40, registered N386MA, was substantially damaged in an accident during landing (flare/touchdown) near Benson, Arizona (Benson Muni 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 nose landing due to fatigue cracking.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 20, 2020 · about 4:50 am local time
- Place
- Benson, Arizona · Benson Muni · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Diamond DA 40, built 2004
- Registration
- N386MA · registry record · serial 40.449
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilots were performing an instructional flight and completed a normal approach to the destination runway. The main landing gear touched down on the runway surface first and as soon as the nose lowered, the nose landing gear collapsed. The nose landing gear fork assembly had collapsed when a pivot-axle welded to the arm in the nose landing gear welding assembly fractured. A metallurgical examination revealed the pivot-axle fracture surface exhibited two opposite facing fatigue cracks propagating inward on the pivot-axle due to reverse bending, consistent with repeated landing forces and cycles prior to the accident. The cracks propagated until the remaining pivot-axle cross section could not withstand the loads on the last landing cycle and succumbed to fracture from overstress. The location of the crack’s origins required disassembly to detect. Therefore, it would not have been easily detected during routine maintenance. Following this accident, the manufacturer issued a mandatory service bulletin to routinely inspect the nose landing gear for cracks using dye penetrant.
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
- Landing gear collapse during landing (flare/touchdown) defining event
The NTSB's findings
- Aircraft › Aircraft systems › Landing gear system › Nose/tail gear strut/axle › Fatigue/wear/corrosion
Flight instructor
- Certificate: flight instructor
- Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 375 hours in all; 22 in this make and model; 23 in the last 90 days; 22 in the last 30 days; 336 as pilot in command; 10 on instruments
- Last flight review: January 29, 2020
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
Dual student
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 240 hours in all; 43 in this make and model
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 8,528 hours
- Last inspection: approved inspection programme, August 10, 2020; 40 hours since
- Maximum gross weight: 2,535 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO-360-M1A (piston); 3,371 hours total
- Operator: Cae Oxford Aviation Academy
The flight
- Departed from: FFZ Mesa AZ at 3:35 am
- Destination: E95 Benson AZ
- Flight plan: VFR
- Runway 10, 4,002 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 330° at 6 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 100°F (38°C), dew point 46°F (8°C)
- Altimeter: 29.86 inHg
- Observation at 3:53 am from KTUS, 31 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
4 documents, released by the NTSB on September 7, 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 | Materials Laboratory Factual Report | PDF, 19 pages | View Download |
| 2 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 30 pages | View Download |
| 3 | Record of Conversation | PDF, 1 page | View Download |
| 4 | Statement of Party Representatives to NTSB Investigation | PDF, 2 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.