Robinson R44 II N324RS

Summary

On 29 December 2016 at about 19:31 local time, a Robinson R44 II registered N324RS was involved in an accident near Mt. Baldy, California, United States. 4 people were on board and one was seriously injured, 3 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

29 December 2016 at 19:31

Classification

Accident

Location

Mt. Baldy, California, United States

Coordinates

34.2878, -117.6514

Aircraft

Robinson R44 II

Registration

N324RS

Category

Helicopter

Year built

2003

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Fullerton → Mt. Baldy

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR17LA043

1 person was seriously injured.

The pilot's failure to maintain main rotor speed during a low orbiting approach over a confined mountainous area. Contributing to the accident was the pilot's decision to attempt to land in an area that did not allow for a safe exit path under conditions near the limit of the helicopter’s performance capability.

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

Read the full NTSB narrative

The commercial pilot planned to land the helicopter at the top of a high mountain peak. Three passengers were onboard, and the helicopter was loaded just below its maximum gross weight. The enroute climb was uneventful, and after reaching the peak, the pilot performed an orbit over the landing site. While surveying his landing options, the helicopter's low rotor rpm warning horn sounded, and he corrected by lowering the collective and increasing engine power. The horn stopped, and he continued to circle the area while reviewing an engine limit manifold pressure chart and determining that he had enough engine power available to proceed. Hikers were close to his intended landing area, so he initiated an approach with a tailwind toward the lower face of a ridgeline with the intention of turning back to land into the wind. As he approached the landing spot, the low rotor rpm horn sounded again, and he lowered the collective. The helicopter descended rapidly, and due to terrain, there was no escape path, so he warned the passengers to brace for impact. The helicopter landed hard and sustained substantial damage. The helicopter was operating at the upper limit of its performance capabilities at the reported gross weight and calculated density altitude. Performance charts indicated that the helicopter would not have been able to hover at that altitude, and as such, a successful landing, while not impossible, would have been challenging. The activation of the warning horn during the initial orbit would have been another indication to the pilot that there was limited engine power available for landing. The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation, and the accident is consistent with the pilot's failure to maintain rotor rpm while operating near the helicopter's performance limits.

Quoted verbatim from the NTSB record.