Tail Rotor Separation Leads to Helicopter Ditching in Guanabara Bay

Casualties unknown • RIO DE JANEIRO, RJ, BR

An instructional flight in a Robinson R22 BETA ended in a water ditching after the aircraft suffered a catastrophic failure of its antitorque system.

What happened

On July 6, 2020, an R22 BETA helicopter, registration PR-OEA, was conducting a local instructional flight departing from Jacarepaguá (SBJR) in Rio de Janeiro. The aircraft was occupied by two pilots, including an instructor and a student pilot undergoing training for a commercial license.

Approximately 20 minutes into the flight, the crew reported hearing an abnormal noise followed by significant vibrations and a loss of pedal control. Surveillance footage from the area captured the aircraft performing a left turn before entering a steep descent. The helicopter began rotating rapidly to the right around its vertical axis, completing more than three full turns before impacting the surface of Guanabara Bay. The aircraft remained submerged until it was later recovered by a crane-barge.

The investigation

CENIPA investigators examined the wreckage and recovered portions of the tailboom and the Tail Gear Box (TGB). The investigation established that the aircraft sustained substantial damage to the cabin, tail boom, main rotor blades, and tail assembly.

Analysis of the recovered components revealed that the TGB housing and the tail rotor output shaft exhibited fractures consistent with overload failure. Furthermore, the tail-rotor pitch-control rod showed significant elongation and torsional deformation, indicating it had been subjected to extreme tensile loads. The investigation also noted that the attachment points for the long tail rotor drive shaft to the TGB were ovalized. While the tailboom and TGB were recovered, the tail rotor itself, the rotor hub, and the output shaft were not located.

Findings

  • The pilots were qualified, experienced in the aircraft type, and held valid medical certificates.
  • Meteorological conditions were well within the required minimums for the flight.
  • The aircraft's maintenance records were up to date, and the most recent 100-hour inspection had been completed recently.
  • The in-flight separation of the tail rotor components caused the loss of directional stability.
  • The failure of the antitorque system was characterized by a mechanical failure in the rotor hub or pitch control assembly that triggered a chain of structural overloads, leading to the separation of the tail rotor and the tailboom structure.

Probable cause

The accident was caused by the in-flight separation of the tail rotor and components of the antitorque system, which led to a total loss of directional control and a subsequent uncontrolled impact with the water.

Frequently asked questions

What happened in the 2020-07-06 aircraft accident near RIO DE JANEIRO, RJ, BR?

An instructional flight in a Robinson R22 BETA ended in a water ditching after the aircraft suffered a catastrophic failure of its antitorque system.

What aircraft was involved and where did it happen?

The accident on 2020-07-06 involved a aircraft, registration PROEA, at RIO DE JANEIRO, RJ, BR.

What was the probable cause of the accident?

The accident was caused by the in-flight separation of the tail rotor and components of the antitorque system, which led to a total loss of directional control and a subsequent uncontrolled impact with the water.

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