National Transportation Safety Board
Aviation Accident Final Report

 

 

Location:

Big Bear, CA

Accident Number:

WPR15LA014

Date & Time:

10/16/2014, 1400 PDT

Registration:

N612SP

Aircraft:

CESSNA 172S

Aircraft Damage:

Substantial

Defining Event:

Loss of engine power (partial)

Injuries:

3 Serious

Flight Conducted Under:

Part 91: General Aviation - Personal

Analysis

 

The commercial pilot was conducting a personal cross-country flight during daytime visual meteorological conditions over mountainous terrain. He reported that, about 30 minutes into the flight, the engine began to lose power. The airplane descended into a box canyon, and the pilot then attempted to maneuver the airplane to initiate a 180-degree turn out of the canyon toward lower terrain. The airplane continued to descend, and the stall warning horn sounded, so the pilot decided to land in trees.

First responders reported that the wing fuel tanks were breached and that fuel had drained out through holes in the wings. A postaccident examination of the airframe and engine revealed no evidence of any preexisting mechanical malfunctions or failures that would have precluded normal operation. The reason for the partial loss of engine power could not be determined.

 

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
 

A partial loss of engine power for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.

 

 

Findings

Environmental issues

Mountainous/hilly terrain - Contributed to outcome

Tree(s) - Contributed to outcome

Not determined

Not determined - Unknown/Not determined (Cause)

Factual Information

History of Flight

Enroute-cruise

Loss of engine power (partial) (Defining event)

Collision with terr/obj (non-CFIT)

 

On October 16, 2014, about 1400 Pacific daylight time, a Cessna 172S, N612SP, was substantially damaged when it collided with terrain near Big Bear City Airport (L35), Big Bear, California. Sohail Air Ventures LLC was operating the rental airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The commercial pilot and two passengers sustained serious injuries. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight. The cross-country flight departed Corona, California, at an undetermined time with an intended destination of L35.

According to a Federal Aviation Administration (FAA) inspector, the pilot reported that he intended on flying to L35 for lunch prior to returning to Corona. Prior to the flight, he verified the fuel level of each fuel tank at 11 to 12 gallons of fuel and noted that the airplanes log sheet indicated 13 gallons of fuel should have been in each wing's fuel tank. The pilot further reported to the inspector that he anticipated getting fuel at Big Bear and that he planned to fly directly above the box canyons of the mountainous terrain west of the airport.

The pilot stated that thirty minutes into the flight, he noticed that he could not maintain altitude above the canyons and the engine was losing power. Once inside a box canyon, he maintained a position on the left side of the canyon with the intent to execute a right turn out of the canyon toward lower terrain. As the airplane continued to sink, he noticed that he did not have enough engine power to maintain a close proximity to the face of the mountain. The pilot further stated that when he heard the stall warning horn, he decided to initiate a landing on top of the trees instead of stalling [the airplane]. The pilot added that he had adjusted the mixture early in the flight, but the events of the flight happened too fast to attempt corrective adjustments immediately prior to the accident.

First responders confirmed that the wing fuel tanks were breached, and fuel had drained out through holes in the wings.

 

 

 

Pilot Information

Certificate:

Commercial; Private

Age:

42, Male

Airplane Rating(s):

Multi-engine Land; Single-engine Land

Seat Occupied:

Left

Other Aircraft Rating(s):

None

Restraint Used:

3-point

Instrument Rating(s):

Airplane

Second Pilot Present:

No

Instructor Rating(s):

None

Toxicology Performed:

No

Medical Certification:

Class 2 Without Waivers/Limitations

Last FAA Medical Exam:

 

Occupational Pilot:

Yes

Last Flight Review or Equivalent:

 

Flight Time:

 

 

 

 

 

Aircraft and Owner/Operator Information

Aircraft Make:

CESSNA

Registration:

N612SP

Model/Series:

172S

Aircraft Category:

Airplane

Year of Manufacture:

2000

Amateur Built:

No

Airworthiness Certificate:

Normal

Serial Number:

172S8594

Landing Gear Type:

Tricycle

Seats:

4

Date/Type of Last Inspection:

03/06/2013, Annual

Certified Max Gross Wt.:

2299 lbs

Time Since Last Inspection:

 

Engines:

1 Reciprocating

Airframe Total Time:

1959 Hours as of last inspection

Engine Manufacturer:

LYCOMING

ELT:

Installed

Engine Model/Series:

IO-360-L2A

Registered Owner:

SOHAIL AIR VENTURES LLC

Rated Power:

180 hp

Operator:

SOHAIL AIR VENTURES LLC

Operating Certificate(s) Held:

None

 

 

 

Meteorological Information and Flight Plan

Conditions at Accident Site:

Visual Conditions

Condition of Light:

Day

Observation Facility, Elevation:

L35

Distance from Accident Site:

8 Nautical Miles

Observation Time:

1415 PDT

Direction from Accident Site:

82°

Lowest Cloud Condition:

Clear

Visibility

10 Miles

Lowest Ceiling:

None

Visibility (RVR):

 

Wind Speed/Gusts:

10 knots /

Turbulence Type Forecast/Actual:

/ Unknown

Wind Direction:

260°

Turbulence Severity Forecast/Actual:

/ Unknown

Altimeter Setting:

30.15 inches Hg

Temperature/Dew Point:

20°C / -17°C

Precipitation and Obscuration:

No Obscuration; No Precipitation

Departure Point:

Corona, CA (AJO)

Type of Flight Plan Filed:

None

Destination:

Big Bear, CA

Type of Clearance:

None

Departure Time:

 

Type of Airspace:

 

 

An aviation routine weather report (METAR) for L35, elevation 6,756 feet msl, located about 8 miles northeast of the accident site was issued at 1415. It indicated wind from 260 degrees at 10 knots, 10 miles or greater visibility, sky clear, temperature at 20 degrees C, dew point -17 degrees C, and an altimeter setting at 30.15 inches of mercury. The relative humidity was 7%.

A METAR for San Bernardino International Airport (SBD), elevation 1,159 feet msl, located about 15 miles southwest of the accident site, was issued at 1350. It indicated wind calm, 10 miles or greater visibility, sky few at 5,000 feet, temperature at 24 degrees C, dew point 8 degrees C, and an altimeter setting at 29.96 inches of mercury.

 

 

Wreckage and Impact Information

Crew Injuries:

1 Serious

Aircraft Damage:

Substantial

Passenger Injuries:

2 Serious

Aircraft Fire:

None

Ground Injuries:

N/A

Aircraft Explosion:

None

Total Injuries:

3 Serious

Latitude, Longitude:

34.243611, -117.019444 (est)

 

 

 


 

 

Tests And Research

Examination of the recovered wreckage was conducted on October 28, 2014, by representatives of the FAA, Cessna, and Lycoming Engines under the supervision of the National Transportation Safety Board investigator-in-charge.

Airframe

The electrical master switch was in the ON position. The ignition switch was in the BOTH position with the key in the switch. The auxiliary fuel pump switch was in the ON position. Investigators determined that the fuel selector valve was in the BOTH position. The gascolator contained a clear blue fluid that smelled like aviation gasoline; a water finding paste test had no response indicating that there was no water contamination. The screen was clean.

Engine

Investigators manually rotated the crankshaft with a tool in the vacuum pump drive pad. The crankshaft rotated freely, and the valves moved approximately the same amount of lift in firing order. The accessory gears turned freely. Investigators obtained thumb compression on all cylinders in firing order. A borescope inspection revealed no mechanical deformation on the valves, cylinder walls, or internal cylinder head. When each magneto drive shaft was rotated by hand, both magnetos produced spark at all posts.

The fuel pump's rubber diaphragm was intact and the pump contained a fluid consistent with the appearance and odor of aviation fuel.

Propeller

The two blades were bent and twisted. Both blades exhibited leading edge gouges and chordwise striations.

No evidence of any preexisting mechanical anomalies with the airframe or engine was found that would have precluded normal operation. For further information, see the NTSB Airframe and Engine Examination Notes within the public docket for this accident.

 

Additional Information

Neither the pilot nor the operator submitted an NTSB form 6120.1, Pilot/Operator Aircraft Accident/Incident Report.

 

 


 

 


Administrative Information

Investigator In Charge (IIC):

Howard D Plagens

Report Date:

01/18/2017

Additional Participating Persons:

Rod Ealy; Riverside; Riverside, CA

Mark Platt; Lycoming; Williamsport, PA

Jan Smith; Cessna Aircraft; Wichita, KS

Publish Date:

01/18/2017

Note:

The NTSB did not travel to the scene of this accident.

Investigation Docket:

http://dms.ntsb.gov/pubdms/search/dockList.cfm?mKey=90264