# NTSB NYC79AA106: Mcdonnell Douglas DC9, Boston, MA, September 17, 1979

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Closed
- Date: September 17, 1979, 12:12 local (16:12 UTC)
- Place: Boston, MA
- Coordinates: 42.445278, -70.758331
- Nearby events: https://openairdocs.org/map.md?lat=42.4453&lon=-70.7583&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute-climb to cruise: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330)
- Highest injury: Minor injuries
- Injuries: 1 minor, 44 uninjured
- Status: Completed, report September 19, 2017
- NTSB case key (mKey): 95543
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC79AA106
- Page: https://openairdocs.org/ntsb/NYC79AA106

## Probable cause

a fatigue fracture of the aft cabin pressure bulkhead which resulted in a rapid decompression of the aircraft's cabin area. This fracture initiated from a crack below the aft bulkhead access door which was discernible on the X-rays taken during the aircraft's last maintenance inspection but was not detected by the inspectors.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Fuselage: bulkheads (main fuselage)](https://openairdocs.org/ntsb-findings/01035312): Aircraft › Aircraft structures · Fatigue/wear/corrosion (probable cause); cases with it: [All aircraft, 8 cases](https://openairdocs.org/ntsb-findings/01035312/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Enroute-climb to cruise: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md)

## Analysis

The Safety Board's full report is available at http://www.ntsb.gov/investigations/AccidentReports/Pages/aviation.aspx. The Aircraft Accident Report number is NTSB/AAR-80-13.

At 1212 EDT, on September 17, 1979, Air Canada Flight 680, a scheduled passenger flight to Yarmouth, Nova Scotia, Canada, departed Logan International Airport, Boston, Massachusetts. About 14 min after takeoff, at an altitude of about 25,000 ft msl, the tailcone along with the aft cabin pressure access door and a portion of the aft cabin pressure bulkhead separated from the aircraft causing rapid decompression of the passenger and flightcrew compartments. The aircraft was landed safely at Logan International Airport about 38 min after takeoff. Of the 45 persons aboard, one flight attendant received minor injuries during the decompression. The aircraft's oxygen system and its elevator control and engine control systems were damaged.

## NTSB brief

The Safety Board's full report is available at http://www.ntsb.gov/investigations/AccidentReports/Pages/aviation.aspx. The Aircraft Accident Report number is NTSB/AAR-80-13.

At 1212 EDT, on September 17, 1979, Air Canada Flight 680, a scheduled passenger flight to Yarmouth, Nova Scotia, Canada, departed Logan International Airport, Boston, Massachusetts. About 14 min after takeoff, at an altitude of about 25,000 ft msl, the tailcone along with the aft cabin pressure access door and a portion of the aft cabin pressure bulkhead separated from the aircraft causing rapid decompression of the passenger and flightcrew compartments. The aircraft was landed safely at Logan International Airport about 38 min after takeoff. Of the 45 persons aboard, one flight attendant received minor injuries during the decompression. The aircraft's oxygen system and its elevator control and engine control systems were damaged.

## Aircraft

- Registration: CF-TLU (not matched to a registry record)
- Reported make and model: MCDONNELL DOUGLAS DC9 (32)
- Category: Airplane
- Serial number: 47196
- Year built: 1968
- Airframe hours: 28425
- Engines: Pratt & Whitney JT8D-7 turbo fan; Pratt & Whitney JT8D-7 turbo fan
- Damage: Substantial damage
- Flight: Part 129
- Operator: Air Canada
- Registered owner: Air Canada
- Airworthiness certificate: Standard, Transport
- Departed: BOS, BOSTON, MA
- Destination: Yarmouth
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 44; injuries: none; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1; flight hours: 13,864 total, 1,213 in this make and model
- Co-pilot; age 31; injuries: none; airline transport; airplane ratings: multi-engine land; medical: class 1; flight hours: 6,434 total, 753 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 240° at 10 knots
- Visibility: 15 statute miles
- Temperature: 73 °F, dew point 55 °F
- Altimeter: 30.23 inHg
- Observed at: KBOS, 12 nm away

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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