Amateur-built MOSQUITO XE 285 accident near Odessa, Florida, September 25, 2017
On September 25, 2017 at about 9:40 pm local time, a 2017 amateur-built MOSQUITO XE 285 (helicopter), registered N926KB, was substantially damaged in an accident during enroute (descent) near Odessa, Florida. It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A total loss of engine power due to cold seizure of the No.1 piston, which resulted in its failure and a subsequent emergency autorotation and impact with a house’s roof.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 25, 2017 · about 9:40 pm local time
- Place
- Odessa, Florida · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built MOSQUITO XE 285 NO SERIES, built 2017
- Registration
- N926KB · no longer on the register · serial MXE 1306A17B
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
According to the pilot of the experimental amateur-built helicopter, after departure, the flight was uneventful with no indications of any mechanical problems. After flying around the local area between 800 and 1,000 ft above mean sea level for about 45 minutes, the pilot started to return to the departure site and began a slow descent, after which, he noticed a substantial loss of engine and rotor rpm. He then tried to increase power with no response, so he entered an emergency autorotation and started looking for a landing spot. He aimed to land in an open area, but the helicopter was unable to reach it and impacted a house’s roof. Download and examination of data from the helicopter’s electronic engine monitor indicated that the engine had experienced an overheat event. The overheating was confirmed during a postaccident examination of the helicopter’s engine when it was discovered that the coolant return line, which carried heat away from the engine’s cylinders and was rated for a maximum temperature of 200° F, had melted off its brass connector. Additionally, both the Nos.1 and 2 pistons exhibited scoring on their sides. The No.1 piston’s sides were also fractured, and pieces were missing. Additionally, the No.1 spark plug electrode exhibited evidence of metallic splatter. This evidence indicates that the engine likely experienced cold scoring, which can occur if power is applied before the engine has been brought up to normal operating temperature. When this occurs, it results in the piston heating up and expanding faster than the cylinder, losing clearance between the piston and cylinder, and the piston contacting the sides of the cylinder bore, and seizing. It is likely the No. 1 piston experienced a cold seizure, which resulted in its failure and a subsequent total loss of engine power.
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
- Loss of engine power (total) during enroute (descent) defining event
- Autorotation Collision with terrain or object (not controlled flight into terrain)
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Damaged/degraded
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Failure
Pilot
- Certificate: private
- Ratings: rotorcraft: helicopter
- Flight time: 80 hours in all; 18 in this make and model; 9 in the last 90 days; 1 in the last 30 days; 32 as pilot in command
- Last flight review: July 6, 2017
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: sngl
- Injury: minor injuries
The aircraft
- Airframe total time: 17.5 hours
- Last inspection: condition inspection, April 20, 2017; 17.5 hours since
- Maximum gross weight: 720 lb
- Seats: 1
- Landing gear: fixed
- Engine: Suzuki Inntec 800 (piston); 18 hours total
The flight
- Departed from: Odessa FL at 8:45 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 290° at 8 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 25,000 ft; a few clouds at 3,300 ft
- Temperature: 88°F (31°C), dew point 70°F (21°C)
- Altimeter: 29.82 inHg
- Observation at 9:53 pm from TPA, 9 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on July 20, 2021. 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 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 11 pages | View Download |
| 2 | Witness Statements and Interview Summaries | PDF, 9 pages | View Download |
| 3 | Memorandum for Record - NTSB Engine Examination | PDF, 1 page | View Download |
| 4 | Photo Array | PDF, 18 pages | View Download |
| 5 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | 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.