Cessna 172N accident near Moss Beach, California, November 18, 2016
On November 18, 2016 at about 7:17 pm local time, a 1979 Cessna 172N, registered N6610D, was substantially damaged in an accident during approach (VFR pattern final) near Moss Beach, California (Half Moon Bay airport). It was a personal flight under general aviation rules (Part 91). 1 person was killed and 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's loss of airplane control following an encounter with low level wind shear and turbulence during final approach for landing. Contributing to the loss of control was the pilot's decision to retract the wing flaps on final approach, which resulted in a sudden loss of lift.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 18, 2016 · about 7:17 pm local time
- Place
- Moss Beach, California · Half Moon Bay · map
- Type
- Accident
- Injuries
- 1 person was killed and 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172N N, built 1979 · all 172Ns on the register
- Registration
- N6610D · no longer on the register · serial 17272897
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The private pilot and a passenger were approaching the airport to land with a 70° right crosswind at 10 knots (kts) with gusts to 14 kts. The pilot reported that, on final approach, the airplane was configured with full flaps (30°) at an airspeed of 60 kts, and an altitude of 500 ft mean sea level (msl) when it began to encounter turbulence. The pilot then elected to conduct the landing approach at a higher airspeed and subsequently retracted the flaps from 30° to less than 20°. Immediately after reconfiguring the flaps, the pilot reported that he experienced strong turbulence that violently rocked the airplane and simultaneously felt a "strong downdraft" as the airplane entered a right bank. The pilot was unable to correct the airplane's attitude, and the airplane subsequently descended into terrain, where it impacted a paved road, several vehicles, and two houses before coming to rest. A weather study revealed that, at the time of the accident, a weak temperature inversion was present between 400 and 600 ft msl. The stable layer of air produced by the temperature inversion trapped any updrafts or downdrafts created by the wind flowing over nearby terrain. This created an environment favorable for the development of low level wind shear and turbulence below 600 ft msl. Although airplane performance data revealed that the pilot maintained an airspeed above the airplane's stall speed throughout the landing approach, his decision to retract the flaps likely resulted in a sudden loss of lift. This loss of lift, combined with the low level wind shear and turbulent conditions, most likely resulted in the pilot's loss of control during the approach for landing.
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
- Turbulence encounter during approach (VFR pattern final) defining event
- Loss of control in flight during maneuvering (low-alt flying)
- Collision with terrain or object (not controlled flight into terrain) during approach
The NTSB's findings
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- cause Environmental issues › Conditions/weather/phenomena › Wind › Windshear › Effect on operation
- cause Environmental issues › Conditions/weather/phenomena › Turbulence › Terrain induced turbulence › Effect on operation
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Lateral/bank control › Attain/maintain not possible
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Descent rate › Attain/maintain not possible
- factor Personnel issues › Task performance › Use of equip/info › Use of equip/system › Pilot
- factor Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
- factor Aircraft › Aircraft systems › Flight control system › TE flap control system › Incorrect use/operation
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 1,145 hours in all; 884 in this make and model; 17 in the last 90 days; 10 in the last 30 days; 1,011 as pilot in command
- Last flight review: July 21, 2015
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 5,768 hours
- Last inspection: annual inspection, April 5, 2016; 173 hours since
- Maximum gross weight: 2,299 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-360 SERIES (piston); 1,209 hours total
The flight
- Departed from: SAC Sacramento CA at 6:15 pm
- Destination: HAF Half Moon Bay CA
- Flight plan: none
- Runway 12, 5,000 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 190° at 10 knots, gusting 14
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 63°F (17°C), dew point 37°F (3°C)
- Altimeter: 30.03 inHg
- Observation at 7:15 pm from HAF, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
14 documents, released by the NTSB on February 21, 2018. 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 | Weather Study Report | PDF, 29 pages | View Download |
| 2 | Weather Study Report - Attachment 1 | PDF, 5 pages | View Download |
| 3 | Weather Study Report - Attachment 2 | PDF, 1 page | View Download |
| 4 | Weather Study Report - Attachment 3 | PDF, 2 pages | View Download |
| 5 | Airplane Performance Study | PDF, 10 pages | View Download |
| 6 | Engine Data Monitor - Specialist's Factual Report | PDF, 6 pages | View Download |
| 7 | Engine Data Monitor - Specialist's Factual Report - Attachment 1 | data file | Download |
| 8 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 10 pages | View Download |
| 9 | Summary of Airplane Examination | PDF, 6 pages | View Download |
| 10 | Record of Conversation | PDF, 1 page | View Download |
| 11 | Evidence Control Forms | PDF, 3 pages | View Download |
| 12 | Statement of Party Representatives to NTSB Investigation | PDF, 2 pages | View Download |
| 13 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | View Download |
| 14 | Photo Array of Accident Site | PDF, 5 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.