Mooney M-20K accident near Old Lyme, Connecticut, May 20, 1983
On May 20, 1983 at about 6:20 pm local time, a Mooney M-20K, registered N231HT, was destroyed in an accident near Old Lyme, Connecticut. It was a personal flight under general aviation rules (Part 91). 1 person was killed. The weather was instrument conditions (cloud, fog or low visibility).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 20, 1983 · about 6:20 pm local time
- Place
- Old Lyme, Connecticut
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- instrument conditions (cloud, fog or low visibility)
- Aircraft
- Mooney M-20K · all M-20Ks on the register
- Registration
- N231HT · no longer on the register · serial 25-0267
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE ACFT COLLIDED WITH THE GROUND IN IMC AFTER THE PLT REPORTED HE LOST HIS VACUUM INSTRUMENTS. THE FLT ORIGINATED AT MATTITUCK, NY WITH A DESTINATION OF LEBANON, NH. AFTER DEPARTURE THE PLT WAS CLEARED TO CLIMB TO 7000 FT. THE INSTRUMENTRATED PILOT WAS ON AN IFR FLT PLAN. ABOUT 8 MINUTES AFTER DEPARTURE THE PILOT RADIOED THAT HE HAD EXPERIENCED A LOSS OF VACUUM AND HIS ARTIFICIAL HORIZON WAS INOPERATIVE. HE ALSO STATED HE HAD NO AUTOPILOT AND REQUESTED RADAR VECTORING. HE WAS GIVEN A HEADING OF 050 FOR RADAR VECTORING TO NORWICH VOR. ABOUT 2 MINUTES LATER THE PILOT RADIOED HE WAS 'IN TROUBLE AND IN A DIVE.' ONE MIN LATER HE RADIOED 'ONE THOUSAND FT I AM IN DEEP TROUBLE HERE.' THIS WAS THE LAST RADIO CALL FROM THE PLT. WITNESSES IN THE AREA HEARD & SAW THE ACFT COME OUT OF THE CLOUDS AT 200-300 FT & THEN CLIMB BACK INTO THE FOG BANK. SHORTLY THEREAFTER, A 'WHISTLING DIVE' WAS HEARD FOLLOWED BY THE SOUND OF A CRASH. THE WX IN THAT AREA WAS DESCRIBED AS FOG, LIGHT RAIN, & OVERCAST. EXAM OF THE ACFT WRECKAGE REVEALED THAT THE VACUUM PUMP FAILED.
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
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 3,900 hours in all
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Last inspection: annual inspection, July 14, 1982
- Maximum gross weight: 2,900 lb
- Seats: 4
- Landing gear: retractable
- Engine: Continental TSIO-360-GB (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: Mattituck NY at 2:09 pm
- Destination: LEB Lebanon NH
- Flight plan: IFR
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 220° at 14 knots
- Visibility: 1 statute miles
- Sky: overcast at 700 ft; clear
- Temperature: 54°F (12°C), dew point 0°F (-18°C)
- Altimeter: 30.00 inHg
- Observation at 5:45 pm from GON, 13 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
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.