- Date
- September 22, 1984, 11:30 local (15:30 UTC)
- Place
- Unionville, PA
- Injuries
- 1 serious, 5 minor, 8 uninjured; on the ground: 1 serious, 5 minor
- Damage
- Substantial damage
- Phase of flight
- Approach
- Aircraft
- N79KSikorsky S-76A
- Weather
- Visual (VMC) · Day
- Status
- Completed
- Report
- Approved by Office Director
- Safety recommendations
- Yes
- FAA report
- 19840922076549A
- Case key
- 35370
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
On approach, acft yawed right. Plt reduced power and executed emerg lndg. Before shutdown, it was noted the t/r was stationary while the main rotor continued to turn. Investigation revealed t/r drive shaft had separted due to thermal/mechanical damage incurred by contact with engine firewall. Further investigation revealed that a firewall modification had been designed which included a doubler strip at the fwd and aft firewall section connection. Presence of doubler would decrease clrnc between firewall and t/r shaft. It was further determined that, during installation, the fwd firewall section, to which the doubler is attached, was mispositioned with result that clrnc was reduced to nil. Components came into contact during operations.
Aircraft
- Registration
- N79K
- Reported as
- Sikorsky S-76A
- Category
- Helicopter
- Serial number
- 760098
- Airframe hours
- 1,786
- Engine
- Allison A250C30S, 650 horsepower, turbo shaft
- Damage
- Substantial damage
- Flight
- Part 135
- Registered owner
- Keystone Helicopter Corp.
- Airworthiness certificate
- Standard, Transport
- Last inspection
- 100 hour · June 30, 1984 · 100 hours before
- Departed
- 40N · Coatesville, PA
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 39
- Certificates
- Airline transport, Commercial
- Airplane ratings
- Single-engine land
- Instrument ratings
- Airplane, Helicopter
- Medical
- Class 1, Valid Medical--no waivers/lim.
- Seat
- Right
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 160° at 3 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 70 °F, dew point 52 °F
- Altimeter
- 30.00 inHg
- Observed at
- PNE
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.