Cessna 170B accident near Mahwah, New Jersey, July 19, 2009
On July 19, 2009 at about 3:00 pm local time, a Cessna 170B, registered N8339A, was substantially damaged in an accident during enroute (cruise) near Mahwah, New Jersey (Greenwood Lake Airport). It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power due to the failure of the No. 1 cylinder thru bolt hold down nuts due to corrosion.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 19, 2009 · about 3:00 pm local time
- Place
- Mahwah, New Jersey · Greenwood Lake Airport · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 170B · all 170Bs on the register
- Registration
- N8339A · no longer on the register · serial 25191
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During a cross-country flight, the airplane’s engine began to vibrate heavily, lost all power, and the pilot executed an emergency landing in a field. During the landing roll, the airplane impacted a hill, and sustained substantial damage. On a previous flight, the pilot recalled a vague vibration while en route. A mechanic was unable to identify the source of the vibration, and a "no defects noted" statement was entered into the logbook after various component checks. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the No.1 cylinder revealed that two thru bolt nuts were loose. Two of the other bolts were sheered off, and one was missing. The threads on the thru bolt, with the missing nut, were rusted.
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
- Powerplant sys/comp malf/fail during enroute (cruise) defining event
- Loss of engine power (total) during enroute (cruise)
- Off-field or emergency landing during emergency descent
- Landing area overshoot during landing (flare/touchdown)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Fatigue/wear/corrosion
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; single-engine sea; instrument: airplane
- Flight time: 538 hours in all; 163 in this make and model; 12 in the last 90 days; 8 in the last 30 days; 420 as pilot in command
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 3,584 hours
- Last inspection: annual inspection, March 6, 2009; 15 hours since
- Maximum gross weight: 2,200 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-360-A1A (piston); 0 hours total
The flight
- Departed from: BAF Westfield MA at 1:00 pm
- Destination: TEB Mahwah NJ
- Flight plan: not recorded
Weather at the time
- Light: daylight
- Wind: from 280° at 9 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 73°F (23°C), dew point 52°F (11°C)
- Altimeter: 30.06 inHg
- Observation at 1:51 pm from TEB, 5 miles away
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.
Other NTSB records under N8339A the same tail number, which may have belonged to a different aircraft at the time
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.