Wednesday, August 22, 2018

Robinson R44 Raven, registered to November Alpha LLC and operated by the pilot, N324RS: Accident occurred December 29, 2016 near the peak of Mount San Antonio, Mount Baldy, San Bernardino County, California

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity: 
Federal Aviation Administration / Flight Standards District Office; Riverside, California 

Aviation Accident Factual Report - National Transportation Safety Board: https://app.ntsb.gov/pdf 

Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms 


http://registry.faa.gov/N324RS


Location: Mt. Baldy, CA
Accident Number: WPR17LA043
Date & Time: 12/29/2016, 1131 PST
Registration: N324RS
Aircraft: ROBINSON HELICOPTER COMPANY R44 II
Aircraft Damage: Substantial
Defining Event: Loss of lift
Injuries: 1 Serious, 3 Minor
Flight Conducted Under: Part 91: General Aviation - Personal 

On December 29, 2016, at 1131 Pacific standard time, a Robinson Helicopter Company R44 II, N324RS, landed hard near the peak of Mount San Antonio, Mount Baldy, California. The flight instructor sustained serious injuries, and the three passengers received minor injuries. The helicopter sustained substantial damage during the impact. The helicopter was registered to November Alpha LLC., and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan had been filed. The personal flight departed Fullerton Municipal Airport, Fullerton, California at 1100 with a planned destination of Mount Baldy.

The pilot reported that prior to flight he performed a weight and balance check, and based on the results, he filled the main fuel tank to half of its capacity, and the auxiliary tank to one quarter.

The departure and flight to Mount Baldy were uneventful (Image 1). As the helicopter approached the summit from the south, the pilot noticed a group of hikers on a ridgeline at the top of the mountain. While executing a right turn orbit around the summit the low rotor RPM warning horn sounded. To recover, the pilot lowered the collective and increased engine power with the throttle, and as a result the warning horn sound ceased. He then checked the helicopter's limit manifold pressure placard and, "determined we could pull 19.6 inches of power".

The pilot stated that as he started to descend from the south, he felt the helicopter encounter a tailwind. He decided to change the approach to a low pass in order to circle back to the north and land with a headwind (Image 2). He made the pass at a speed of between 35 to 40 knots however a few seconds later the low rotor RPM horn sounded again. He lowered the collective, but the helicopter rapidly descended towards the mountain face. He reported that he did not have enough altitude to recover, or an escape path to guide the helicopter away from terrain.

He warned everyone that a crash was imminent, and just before colliding with the ground, he applied full left foot pedal and the helicopter landed sideways rather than nose-down. After impact, everyone was able to exit unimpeded and he set the transponder to 7700 and turned the fuel valve to the "off" position.


Image 1 - Approximate Route of Flight
 (Data Provided by Harris Corporation)

Image 2 - Approximate Approach Path
(Data Provided by Harris Corporation)

The helicopter came to rest just below a ridge, at an elevation of 9,860 ft, about 1,500 ft west of the summit of Mount Baldy. The aft fuselage was partially submerged in the snow and had sustained buckling damage through to the tailboom. (Photo 1,2)

The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation.


Photo 1 – Helicopter at the Accident Site

Photo 2 – Helicopter at the Accident Site 

Pilot Information

Certificate: Flight Instructor; Commercial
Age: 26, Male
Airplane Rating(s): None
Seat Occupied: Left
Other Aircraft Rating(s): Helicopter
Restraint Used: 3-point
Instrument Rating(s): Helicopter
Second Pilot Present: Yes
Instructor Rating(s): Instrument Helicopter
Toxicology Performed: Yes
Medical Certification: Class 1 With Waivers/Limitations
Last FAA Medical Exam: 10/01/2016
Occupational Pilot: Yes
Last Flight Review or Equivalent: 04/09/2016
Flight Time:  487 hours (Total, all aircraft), 300 hours (Total, this make and model), 461 hours (Pilot In Command, all aircraft), 2.5 hours (Last 90 days, all aircraft), 0.5 hours (Last 30 days, all aircraft), 0 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: ROBINSON HELICOPTER COMPANY
Registration: N324RS
Model/Series: R44 II II
Aircraft Category: Helicopter
Year of Manufacture: 2003
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 10067
Landing Gear Type: Ski;
Seats: 4
Date/Type of Last Inspection: 12/10/2016, 100 Hour
Certified Max Gross Wt.: 2500 lbs
Time Since Last Inspection: 28 Hours
Engines: 1 Reciprocating
Airframe Total Time: 789.4 Hours as of last inspection
Engine Manufacturer: LYCOMING
ELT: Not installed
Engine Model/Series: IO-540-AE1A5
Registered Owner: NOVEMBER ALPHA LLC
Rated Power: 245 hp
Operator: On file
Operating Certificate(s) Held: None

The helicopter was manufactured in 2003 and was equipped with a Lycoming IO-540-AE1A5 engine, serial number RL-26858-48E. On July 6, 2015, both a helicopter overhaul and engine rebuild were completed. The most recent maintenance event was for a 50/100-hour inspection, which was completed on December 10, 2016, 28 flight-hours before the accident. At the time of inspection, the airframe and engine had accumulated 789.4 flight hours since overhaul/rebuild. 



Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KONT, 997 ft msl
Distance from Accident Site: 13 Nautical Miles
Observation Time: 1953 UTC
Direction from Accident Site: 180°
Lowest Cloud Condition: Few / 18000 ft agl
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: Calm /
Turbulence Type Forecast/Actual: /
Wind Direction:
Turbulence Severity Forecast/Actual: /
Altimeter Setting: 30.11 inches Hg
Temperature/Dew Point: 22°C / 0°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: FULLERTON, CA (FUL)
Type of Flight Plan Filed: None
Destination: Mt. Baldy, CA
Type of Clearance: None
Departure Time: 1100 PST
Type of Airspace: Class G

An upper air sounding for the accident site was created utilizing the Weather Research and Forecasting (WRF) computer model. The data indicated that at 1100, at an elevation of 9,920 ft mean sea level, the temperature would have been about 5.4 °C, and dew point -13.9 °C. It indicated wind from 147° at 12 knots.

Utilizing these values and the 1053 pressure reading (30.15 inches of mercury) at Ontario International Airport, Ontario, California, the density altitude at the accident site would have been about 10,900 ft.

A Los Angeles County Sheriff's deputy, who arrived at the accident site via helicopter at 1330, reported that the temperature was 10 °C, with wind from the east at 10 to 15 knots.



Wreckage and Impact Information

Crew Injuries: 1 Serious
Aircraft Damage: Substantial
Passenger Injuries: 3 Minor
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries:  1 Serious, 3 Minor
Latitude, Longitude:  34.287778, -117.651389

Additional Information

Weight

The pilot and front seat passenger weighed 145 and 235 pounds respectively. The total weight of the rear seat occupants and their baggage was 399 pounds. Based on the pilot's statement regarding fuel quantity, the main tank would have contained 15.25 gallons (91.5 pounds) and the auxiliary tank 4.25 gallons (25.5 pounds) of fuel at takeoff.

According to the helicopters most recent weight and balance sheet, the maximum gross weight was 2,500 pounds, and the helicopters basic empty weight was 1,565.2 pounds. Utilizing these values, the helicopter was about 38.8 pounds short of its maximum gross weight at takeoff.



Performance

The performance section of the R44 II Pilot Operating Handbook (POH), stated that the in ground effect (IGE) hover ceiling, based on full throttle, zero wind, and a gross weight of 2,460 pounds was about 8,800 ft at 5 °C, and 9,400 ft at -5 °C. The out of ground effect (OGE) hover ceiling for the same parameters was about 5,400 ft, and 6,600 ft respectively.

The limitations section of the POH stated a maximum operating density altitude of 14,000 feet.

Manifold Pressure Chart

The helicopter was equipped with a manifold pressure chart, which was required to be in full view and readable by the pilot in flight. The intent of the chart was to provide the pilot with the engines maximum allowable continuous manifold pressure at varying temperatures and pressure altitudes. The chart was not intended for determining power available. The pilots reference to "19.6 inches of power" corresponded to a pressure altitude of 10,000 ft, and an outside temperature of –10°C.

NTSB Identification: WPR17LA043
14 CFR Part 91: General Aviation
Accident occurred Thursday, December 29, 2016 in Mt. Baldy, CA
Aircraft: ROBINSON HELICOPTER COMPANY R44 II, registration: N324RS
Injuries: 1 Serious, 3 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On December 29, 2016, at 1131 Pacific standard time, a Robinson Helicopter Company R44 II, N324RS, landed hard near the peak of Mount Baldy, in San Bernardino County, California. The helicopter was registered to November Alpha LLC., and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91. The commercial pilot sustained serious injuries, and the three passengers were not injured. The helicopter sustained substantial damage during the accident sequence. The personal flight departed Fullerton Municipal Airport, Fullerton, California at 1100 with a planned destination of Mount Baldy. Visual meteorological conditions prevailed and no flight plan had been filed.

The pilot reported that prior to flight, he performed a weight and balance check, and based on the results, he filled the main fuel tank to half of its capacity, and the auxiliary tank to one quarter.

The departure and flight were uneventful, and he approached the peak of Mount Baldy from the south with the intention of performing an orbit to survey a site for landing. He estimated the wind to be about 5 knots out of the south as he approached, and during the orbit, he could see hikers at the intended landing spot. As he continued to survey the area, the helicopters low rotor RPM warning horn sounded. He lowered the collective and rolled on the throttle, and the warning stopped. He then checked the manifold pressure, which was between 18 and 19 inches of mercury, and decided that he had enough power available to proceed. He continued with a low pass over a ridge, to signal his intent to the hikers that he wished to land at their location.

He returned to the landing site, and in order to avoid the hikers, he positioned the helicopter to approach from the south-southeast. He could feel a tailwind as they approached the landing site, and the low RPM horn sounded again. He lowered the collective, but the helicopter rapidly descended towards the mountain face directly ahead. He warned everyone that a crash was imminent, and just before colliding with the ground, he applied full left foot pedal in an effort to land sideways rather than nose-down. After impact, everyone was able to exit unimpeded, and he set the transponder to 7700, and turned the fuel valve to the "off" position.

The helicopter came to rest on a ridge, 1/3 of a mile west of the summit of Mount Baldy, at an elevation of 9,860 ft. The aft fuselage was partially submerged in the snow, and had sustained buckling damage through to the tailboom.

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