Boeing 767 432ER incident near St. Johns, Ca, September 8, 2009
On September 8, 2009 at about 1:00 am local time, a 2001 Boeing 767 432ER, registered N840MH, suffered minor damage in an incident during enroute (cruise) near St. Johns. It was flown under scheduled airline rules (Part 121). The NTSB record does not give the injuries. The weather was conditions the NTSB did not record.
The NTSB's probable cause their words, unchanged
Incorrect installation of a wire bundle, which contained wires for oxygen system, passenger address system and lavatory power, led to chafing of the wires on structure. The chafing eventually exposed the wire conductors and resulted in electrical arcing, malfunction of the affected systems and a sulfur odor.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 8, 2009 · about 1:00 am local time
- Place
- St. Johns, Canada · map
- Type
- Incident
- Injuries
- The NTSB record does not give the injuries.
- Weather
- conditions the NTSB did not record
- Aircraft
- Boeing 767 432ER 432ER, built 2001 · all 767 432ERs on the register
- Registration
- N840MH · registry record · serial 29718
- Damage
- Minor damage
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The Delta Airlines 767 was two hours enroute from John F. Kennedy International Airport (JFK) to Venice Marco Polo Airport (VCE), when the cabin lights flickered, the passenger address system was intermittent and then inop, the left side oxygen masks deployed and a sulphur smell was observed, but no smoke. The flight diverted to ATL and landed without incident. Examination of the area above the forward lavatory on the left side revealed fractured wires, sooted equipment, and chafed structure. Drawings showed the wire bundle was incorrectly routed. These findings indicated that the incorrect routing allowed the wires to chafe over time. This chafe eventually exposed the conductor(s) and either two wires or a wire to grounded structure resulted in a electrical short with arcing. A review of the wire functions within the bundle showed wires related to oxygen system, passenger address system, and lavatory power. This is consistent with the reported anomalies.
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
- Electrical system malf/failure during enroute (cruise) defining event
The NTSB's findings
- cause Aircraft › Aircraft systems › Oxygen system › Oxygen sys wiring › Damaged/degraded
The aircraft
- Landing gear: fixed
- Operator: Delta Air Lines INC
The flight
- Departed from: JFK New York NY
- Destination: VCE Venice
- Flight plan: not recorded
- A second pilot was aboard
Weather at the time
- Light: not reported
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
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.