Robinson R22 BETA II N7041X

Summary

On 30 December 2014 at about 02:00 local time, a Robinson R22 BETA II registered N7041X was involved in an incident near Phoenix, Arizona, United States. One person was on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

30 December 2014 at 02:00

Classification

Incident

Location

Phoenix, Arizona, United States

Nearest airport

Phoenix-Mesa Gateway (IWA)

Coordinates

33.3078, -111.6556

Aircraft

Robinson R22 BETA II

Registration

N7041X

Category

Helicopter

Year built

2014

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Chandler → Chandler

Aircraft damage

Not recorded

Weather

VMC

Light

Night

NTSB number

WPR15IA080

Nobody was injured.

The failure of the fanshaft due to fatigue.

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

Read the full NTSB narrative

The private pilot reported that he was practicing for the commercial pilot helicopter examination and was operating in the airport traffic pattern. The pilot stated that, while entering downwind, he climbed the helicopter to 1,900 ft and was accelerating it to 75 knots when he felt an "abnormal vibration" and smelled "something…burning." The low rotor rpm light illuminated, and the low rotor rpm horn sounded. He subsequently entered an autorotation, made an emergency call, and landed successfully off the runway on dirt. Postaccident examination of the helicopter revealed that the fanshaft had fractured circumferentially; the helicopter had a total time of 337 hours. Examination of the fanshaft revealed a crack in the fanwheel's base, which had beach marks that ran from the fanshaft's bearing surface out and down to the mounting surface, consistent with fatigue. The roller bearings and the races bearing surfaces had minor surface damage. The bearings and races were cut away from the fan shaft, which revealed a v-shaped fracture surface that had two cracks emanating from it. This area had sustained damage from the two halves contacting each other with every rotation of the crankshaft, and some material was missing. The fracture origin could not be determined due to the damage. The only anomaly identified during the examination was that the fanwheel was out of balance; however, this likely resulted from the fanshaft failure.

Quoted verbatim from the NTSB record.