# NTSB BFO91LA055: Boeing 747-400, Philadelphia, PA, June 16, 1991

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: June 16, 1991, 15:00 local (19:00 UTC)
- Place: Philadelphia, PA
- Coordinates: 39.889434, -75.230934 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.8894&lon=-75.2309&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 5 minor, 272 uninjured
- Status: Completed, report August 13, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 11682
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO91LA055
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/11682/pdf
- Page: https://openairdocs.org/ntsb/BFO91LA055

## Probable cause

FAILURE OF THE PILOT TO ENSURE CABIN CREW MEMBERS WERE PREPARED FOR AN ENCOUNTER WITH TURBULENCE.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight encounter with weather, descent - normal
  - weather condition - turbulence (contributing factor)
  - procedures/directives - not followed, pilot in command (cause)

## Analysis

THE FLIGHT WAS ON A CRUISE DESCENT AT 20,000 FEET MSL WHEN IT ENCOUNTERED TURBULENCE, CAUSING INJURIES TO CABIN CREWMEMBERS INCLUDING ONE WHO WAS SERIOUSLY INJURED.  THE PILOT REPORTED THAT HE WAS DEVIATING AROUND CUMULONIMBUS CLOUDS WHEN HE INADVERTENTLY ENTERED ONE.  HE SAID THE SEAT BELT SIGN WAS ON AT THE TIME.  THE FLIGHT PROCEEDED TO THE DESTINATION AND LANDED WITHOUT FURTHER INCIDENT.

## Aircraft

- Registration: PHBFG (not matched to a registry record)
- Reported make and model: BOEING 747-400
- Category: Airplane
- Engines: turbo fan
- Damage: No damage
- Flight: Part 129
- Operator: Klm Royal Dutch Airline
- Registered owner: Klm Royal Dutch Airline
- Airworthiness certificate: Standard, Transport
- Last inspection: Unknown, January 2, 2000
- Departed: AMS, AMSTERDAM, OF
- Destination: BWI, BALTIMORE, MD

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 54; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; flight hours: 15,016 total, 134 in the last 90 days, 65 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 200° at 3 knots
- Visibility: 8 statute miles
- Lowest ceiling: 7,000 ft broken
- Temperature: 81 °F, dew point 72 °F
- Altimeter: 29.00 inHg
- Observed at: PHL, 999 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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