Cessna 152 and Mooney M20D mid-air collision near Half Moon Bay, California, May 28, 1984
On May 28, 1984 at about 10:15 pm local time, 2 aircraft, Cessna 152 (N5157B) and Mooney M20D (N1920Y), were involved in a mid-air collision near Half Moon Bay, California (Half Moon Bay airport). 2 people were killed, 1 person was seriously injured and 2 people had minor injuries. The weather was visual conditions (good weather).
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 28, 1984 · about 10:15 pm local time
- Place
- Half Moon Bay, California · Half Moon Bay · map
- Type
- Accident · mid-air collision
- Injuries
- 2 people were killed, 1 person was seriously injured and 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Cessna 152 · all 152s on the register
- Registration
- N5157B · no longer on the register · serial 15283781
- Damage
- Destroyed
- Flight
- Instructional flight · general aviation rules (Part 91)
- Aircraft 2
- Mooney M20D · all M20Ds on the register
- Registration
- N1920Y · no longer on the register · serial 215
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative for the Cessna 152 final · quoted from the NTSB record
THE TWO ACFT COLLIDED AFTER N1920Y MADE A RADIO CALL TO ANNOUNCE HIS INTENTIONS OF TAKING OFF. N5157B WAS IN A STEEP DESCENT AT MIDFIELD WHEN HE COLLIDED WITH THE TOP REAR PORTION OF N1920Y. THE COLLISION OCCURRED AT ABOUT 75 FT AGL. THE TWO ACFT CRASHED ON THE ARPT. OTHER ACFT IN THE AREA AT THE TIME OF THE ACCIDENT REPORTED THAT NO RADIO TRANSMISSION WAS HEARD FROM N5157B ANNOUNCING HIS INTENTIONS.
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 NTSB's narrative for the Mooney M20D final · quoted from the NTSB record
THE TWO ACFT COLLIDED AFTER N1920Y DECLARED HIS INTENTION TO TAKEOFF AND WAS AIRBORNE APRX HALF WAY DOWN THE RWY. THE OTHER ACFT WAS IN A STEEP DESCENT AT MID-FIELD WHEN HE DOVE INTO N1920Y. BOTH ACFT THEN CRASHED UNCONTROLLED INTO THE GROUND FROM AN ALT OF ARPX 75 FT AGL.
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 for the Cessna 152 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 11,000 hours in all; 5,000 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 2,669 hours
- Last inspection: 100-hour inspection, April 27, 1984; 76 hours since
- Maximum gross weight: 1,670 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-235-L2C (piston); 0 hours total
- Operator: Skyway Aviation INC
The flight
- Departed from: SQL San Carlos CA at 9:36 pm
- Destination: HAF
- Flight plan: none
- Runway 12, 500 ft by 150 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 180° at 8 knots
- Visibility: 25 statute miles
- Sky: clear
- Temperature: 75°F (24°C), dew point 0°F (-18°C)
- Observation at 10:12 pm from HAF
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
The factual record for the Mooney M20D from the NTSB's investigation tables, in plain English
Pilot
- Certificate: private
- Ratings: single-engine land
- Medical certificate: None
- Seat: left
The aircraft
- Airframe total time: 3,446 hours
- Last inspection: annual inspection, August 29, 1983; 69 hours since
- Maximum gross weight: 2,500 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-360 (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: HAF at 10:14 pm
- Destination: APC Napa CA
- Flight plan: none
- Runway 12, 5,000 ft by 150 ft
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 | 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.