Cessna 210 accident near Marianna, Florida, March 18, 2021
On March 18, 2021 at about 5:53 pm local time, a 1979 Cessna 210, registered N7736K, was substantially damaged in an accident during enroute near Marianna, Florida (Marianna Municipal airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 3 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 alternator control unit housing plug connection, which resulted in insufficient battery power to fully extend the landing gear. Contributing to the accident was the pilot’s decision to not use the emergency gear extension handle to secure the gear prior to landing.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 18, 2021 · about 5:53 pm local time · cases in 2021
- Place
- Marianna, Florida · Marianna Municipal · cases near this airport · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 210 N, built 1979 · all 210s on the register
- Registration
- N7736K · registry record · serial P21000420
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot was diverting to an airport to refuel when the airplane’s turbine inlet temperature (TIT) warning light illuminated. Shortly after, the autopilot “fail” light came on and the autopilot disengaged, followed by other electrical components losing power or ability to operate. The pilot said that he was able to extend the landing gear, but the light that confirmed that the gear was down and locked was not working. He said that the gear sounded and appeared to be fully extended, so he chose not to use the emergency gear extension handle to make sure the gear was fully extended. On the subsequent landing rollout, both main landing gear collapsed, resulting in substantial damage to the left horizontal stabilizer. Postaccident examination of the airplane revealed that the housing plug for the alternator control unit (ACU) was loosely fitted and not properly mated. It is likely the housing plug came loose during turbulence, and the battery drained to a point that it could not provide adequate electricity to fully extend and lock the landing gear. The pilot reported no previous issues with the electrical system and no maintenance had been done to the ACU after a recent annual inspection.
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
- Electrical system malf/failure during enroute defining event
- Landing gear collapse during landing (landing roll)
- Landing gear not configured during landing (flare/touchdown)
The NTSB's findings
- Aircraft › Aircraft systems › Electrical power system › Electrical pwr sys wiring › Inoperative other cases naming the electrical power
- Aircraft › Aircraft systems › Electrical power system › Battery/charger › Damaged/degraded other cases naming the electrical power
- Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
- Aircraft › Aircraft systems › Landing gear system › Gear extension and retract sys › Not used/operated other cases naming the landing gear
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 882 hours in all; 306 in this make and model
- Last flight review: November 30, 2020
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 4,041 hours
- Last inspection: annual inspection, March 10, 2021; 7.4 hours since
- Maximum gross weight: 4,000 lb
- Seats: 6
- Landing gear: retractable
- Engine: Continental TSIO 520P6 (piston); 4,041 hours total
The flight
- Departed from: SAV Savannah GA at 3:42 pm
- Flight plan: none
- Runway 18, 6,001 ft by 100 ft
Weather at the time
- Light: daylight
- Wind: from 210° at 15 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 79°F (26°C), dew point 54°F (12°C)
- Altimeter: 29.79 inHg
- Observation at 12:40 pm from KMAI
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 2 |
Photographs from the investigation 2 pictures from the NTSB's docket, as the NTSB released them
Photo 1 – Left side View of Airplane at Accident Site (photo
Photo 2 – Damage to Left Horizontal Stabilizer (photoThe NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.
Documents from the investigation the NTSB's docket: the evidence folder behind the report
6 documents, released by the NTSB on August 3, 2021. 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 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | NTSB Record of Conversation - Pilot | PDF, 1 page | View Download |
| 3 | Written Statement - FAA | PDF, 1 page | View Download |
| 4 | Maintenance Records - Last Annual Inspections | PDF, 3 pages | View Download |
| 5 | Photos | PDF, 2 pages · our copy | View Download |
| 6 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N7736K the same tail number, which may have belonged to a different aircraft at the time
Connections how this case links to the rest of the register
- N7736K on the register today · the tail number may have moved to another aircraft since
- Cessna 210 Centurion 1,525 registered today · the model family and its accident history
- Cessna 72,677 aircraft on the register
- Engine: Continental TSIO 520P6 4,110 aircraft carry this series today · as the NTSB recorded it
- Marianna Municipal · nearest airport
- Savannah/Hilton Head International · departed from
- Accidents and incidents in Florida 6,111 since 1982 · 985 in the last ten years
- Florida 21,708 aircraft registered
- Other NTSB records under N7736K 1 records · the number may have belonged to another aircraft at the time
The whole map of how records connect · these connections as data: /graph/accident/ERA21LA159.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.