Cessna 172S accident near San Carlos, California, September 21, 2009
On September 21, 2009 at about 5:30 pm local time, a Cessna 172S, registered N21591, was substantially damaged in an accident during taxi (to runway) near San Carlos, California (San Carlos airport). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The student pilot's failure to maintain clearance with a fence post during taxi.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 21, 2009 · about 5:30 pm local time
- Place
- San Carlos, California · San Carlos · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172S · all 172Ss on the register
- Registration
- N21591 · registry record · serial 172S9658
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The student pilot's attention was momentarily diverted as he was taxiing around another airplane to the runup area. The pilot subsequently heard the right wing impact a fence post, which resulted in substantial damage to the wing's leading edge.
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
- Ground collision during taxi (to runway) defining event
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring environment › Student pilot
- cause Environmental issues › Physical environment › Object/animal/substance › Fence/fence post › Response/compensation
Dual student
- Certificate: student
- Flight time: 108 hours in all; 108 in this make and model; 20 in the last 90 days; 12 in the last 30 days; 15 as pilot in command
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 2,450 hours
- Last inspection: annual inspection, April 17, 2009
- Maximum gross weight: 2,250 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO-360-L2A (piston); 0 hours total
The flight
- Departed from: SQL San Carlos CA
- Destination: SQL San Carlos CA
- Flight plan: not recorded
- Runway 12, 2,600 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: at 4 knots
- Visibility: 5 statute miles
- Sky: scat at 800 ft
- Temperature: 64°F (18°C), dew point 59°F (15°C)
- Altimeter: 30.01 inHg
- Observation at 4:50 pm from SQL
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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.