Cessna 210 accident near Ramona, California, June 1, 2018
On June 1, 2018 at about 6:18 pm local time, a 1970 Cessna 210, registered N9410M, was substantially damaged in an accident during landing (landing roll) near Ramona, California (Ramona airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The failure of the engine-driven hydraulic pump due to the installation of improper cap screws, which resulted in a gap in the pump housing, a subsequent hydraulic leak, and the landing gear collapsing.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 1, 2018 · about 6:18 pm local time
- Place
- Ramona, California · Ramona · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 210 K, built 1970 · all 210s on the register
- Registration
- N9410M · registry record · serial 21059310
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The private pilot was conducting a personal, cross-country flight. He reported that he attempted to lower the retractable landing gear during a visual approach; however, the right main landing gear (MLG) did not fully extend. He attempted to manually pump the landing gear down with the emergency hand pump, but it was very difficult to move, and after several pumps, it would not move at all. Upon landing, the right MLG collapsed and the airplane impacted the ground, which resulted in substantial damage to the right horizontal stabilizer and elevator. Postaccident examination and tests revealed that, when the MLG system was tested using the airplane’s engine-driven hydraulic pump, fluid started leaking from a gap in the pump’s diaphragm seal between the front plate assembly and the rear housing assembly, and the MLG would not extend. Subsequently, the MLG system was tested with an external hydraulic pump, and it functioned properly. The two front plate cap screws on the side of the leaking pump gap were loose, had only three or four threads engaged with the rear assembly, and had insufficient shank length. The corresponding rear housing internal threads were sheared. Due to the installation of cap screws with insufficient shank length, fewer threads were engaged when the screws were tightened. The insufficient length of the shanks likely led to excessive force being applied on the engaged threads when the cap screws were installed, the threads being damaged, and a gap in the pump housing to develop, which allowed fluid to leak from the pump when it was pressurized. The hydraulic leak prevented the right MLG from fully extending and resulted in it collapsing upon 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
- Landing gear collapse during landing (landing roll) defining event
- Aircraft maintenance event during prior to flight
- Sys/Comp malf/fail (non-power) during approach
The NTSB's findings
- Aircraft › Fluids/misc hardware › Fluids › Hydraulic fluid › Related operating info
- Aircraft › Aircraft systems › Landing gear system › Main landing gear › Malfunction
- Aircraft › Aircraft systems › Hydraulic power system › Pump, main › Incorrect service/maintenance
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 1,951 hours in all; 1,432 in this make and model; 13 in the last 90 days; 12 in the last 30 days
- Last flight review: October 28, 2016
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Last inspection: annual inspection, July 20, 2017; 221 hours since
- Maximum gross weight: 3,803 lb
- Seats: 6
- Landing gear: retractable
- Engine: Cont Motor IO 520-L53B (piston); 221 hours total
The flight
- Departed from: E80 Belen NM at 2:30 pm
- Destination: RNM Ramona CA
- Flight plan: none
- Runway 27, 5,001 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 300° at 6 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 75°F (24°C), dew point 52°F (11°C)
- Altimeter: 29.97 inHg
- Observation at 6:53 pm from KRNM
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 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.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number ANC18LA043.