Bell 206B N89FB

Summary

On 1 August 2001 at about 17:00 local time, a Bell 206B registered N89FB, operated by Helicopter Transport Services, was involved in an accident near Baltimore, Maryland, United States. 2 people were on board and 2 died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

1 August 2001 at 17:00

Classification

Accident

Location

Baltimore, Maryland, United States

Nearest airport

Baltimore-Washington Intl (BWI)

Coordinates

39.1847, -76.6775

Aircraft

Bell 206B

Registration

N89FB

Category

Helicopter

Engines

1

Operator

Helicopter Transport Services

Operating rule

Part 91: General Aviation

Purpose of flight

Aerial Observation

Phase of flight

Not recorded

Route

Baltimore → Baltimore

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

IAD01FA089

2 people died.

The pilot's improper decision to maneuver in an environment conducive to a loss of tail rotor effectiveness, and his inadequate recovery from the resultant unanticipated right yaw.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The purpose of the helicopter flight was to take aerial photographs of a large airport expansion construction project. The helicopter approached the construction site in an out-of-ground-effect hover taxi, with a quartering left tailwind. The helicopter turned to the right, and slowed to a stationary hover about 250 feet above the ground with a direct tailwind. Once in a hover, the helicopter made a right, rapid 180-degree pedal turn around the mast, stopped momentarily, then initiated another rapid pedal turn to the right. The helicopter turned at a faster rate than the initial turn, and continued into a spinning, vertical descent to the ground. Examination of the helicopter revealed no mechanical anomalies. The collective was in the full up position, and the main rotor blades exhibited signatures consistent with low rotor rpm at ground contact. A review of the pilot's company flight records revealed he had 531 hours of total flight experience, 60 hours of which were in airplanes. The pilot had 87 hours of experience in make and model. A relative wind chart published by the manufacturer depicts a helicopter facing 360 degrees over a compass rose. One shaded area of the chart depicts winds from between 120 degrees and 240 degrees, at wind speeds above 5 knots and up to 17 knots. According to a note on the chart an unanticipated right yaw may occur when operating in the shaded areas of the chart. According to FAA Advisory Circular (AC) 90-95, "Any maneuver which requires the pilot to operate in a high power, low airspeed environment with a left crosswind or tailwind creates an environment where unanticipated right yaw may occur." The AC also advised of greater susceptibility for loss of tailrotor effectiveness in right turns and the phenomena may occur in varying degrees in all single main rotor helicopters at airspeeds less than 30 knots.

Quoted verbatim from the NTSB record.