Saturday, March 30, 2019

Loss of Engine Power (Partial): Piper PA-24 Comanche, N7386P, accident occurred April 12, 2018 at New Braunfels Regional Airport (KBAZ), Guadalupe County, Texas

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

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; San Antonio, Texas

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


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


Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf   

http://registry.faa.gov/N7386P




Location: New Braunfels, TX
Accident Number: CEN18LA138
Date & Time: 04/12/2018, 1500 CDT
Registration: N7386P
Aircraft: PIPER PA 24
Aircraft Damage: Substantial
Defining Event: Loss of engine power (partial)
Injuries: 2 Minor
Flight Conducted Under: Part 91: General Aviation - Instructional 

Analysis 

The private pilot was preparing for his commercial checkride with a flight instructor onboard. They had completed several touch-and-go landings when the engine experienced a partial loss of power on the downwind leg of the airport traffic pattern. Attempts to restore power were unsuccessful, and the pilots selected a field for a forced landing. The airplane came to a stop after impacting a fence. A postaccident examination found that fuel was available in both wing tanks. An initial test of the fuel system found that fuel would not flow from the right wing fuel tank; however, the condition could not be replicated during a subsequent test. A test run of the engine revealed no anomalies. The fuel line pickup screen in the right wing fuel tank was clear and no foreign material was observed in the fuel tank.

The carburetor icing probability chart indicated that the airplane was operating in an area associated with a serious risk of carburetor ice accumulation at glide power settings. Despite the risk of carburetor icing, the airplane had completed several takeoffs and landings without problems and the pilots stated that they applied carburetor heat following the loss of power; therefore, it is unlikely that the loss of power was the result of carburetor ice accumulation. The reason for the loss of engine power could not be determined based on the available information. 

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 based on the available information.

Findings

Not determined
Not determined - Unknown/Not determined (Cause)


Factual Information

On April 12, 2018, about 1500 central daylight time, a Piper PA-24 airplane, N7386P, conducted a forced landing near New Braunfels, Texas. The flight instructor and pilot receiving instruction received minor injuries, and the airplane was substantially damaged during the landing. The airplane was registered to and operated by a private individual, under the provisions of 14 Code of Federal Regulations Part 91 training flight. Visual meteorological conditions prevailed at the time.

The pilot reported that he was preparing for his commercial pilot check ride with an instructor. He added that they had been in the traffic pattern for some time and was on the last landing. He configured the airplane for the landing and felt and heard what seemed like the engine smoothly retarding to idle. He informed the instructor that the engine had lost power. He added that they checked the emergency checklist; made sure the fuel pump was on, the mixture was full rich, propeller lever was full forward, fuel selector was on the proper tank, and the carburetor heat was selected.

The flight instructor reported that she heard the engine power decrease and thought the pilot had reduced the power. However, the pilot stated that he lost throttle authority. She then grabbed the throttle and pumped it from idle to full throttle several times, with no response from the engine. She added that both of them, verified the sure the fuel pump was on, the mixture was full rich, propeller lever was full forward, fuel selector was on the proper tank, and the carburetor heat was selected.

Unable to make the runway, the instructor informed the tower controller that they were making a forced landing to a field. The airplane came to a stop after colliding with a fence.

The responding Federal Aviation Administration (FAA) inspector noted fuel was available in both wing fuel tanks, the airplane's landing gear had collapsed and there was substantial damage to the fuselage. The inspector noted that the pilots stated that the fuel selector was on the right-side fuel tank. The inspector conducted an initial test of the fuel system on site, which indicated that fuel would not flow when the right tank was selected.

During recovery, the airplane was placed on stands, with the NTSB Investigator in Charge (IIC), FAA inspectors, and the owner's representative present, the fuel line was disconnected near the engine and the fuel test conducted again. This time, fuel was able when each tank was selected. The airplane was then partially dissembled and transported to a salvage facility.

On April 15, 2018, the NTSB IIC conducted an engine run on the accident airplane. The fuselage, with the wings removed for transport, was placed on a flat bed trailer. In order to run the engine, the damaged 3-bladed propeller and the carburetor air box were replaced. The exhaust pipe was crushed near the tip, so about an 8-inch section of the exhaust pipe was cut off. A fuel can was attached to the fuel line, near the right-wing root location. The engine was primed via the electric boost pump. The engine was then started and run to power. The fuel line was then disconnected and attached to the left side fuel line; the engine test was then repeated. The engine operated without any anomalies noted.

An access cover plate, located on the root end of the right wing, was removed. The fuel tank bladder was opened to allow access into the fuel tank. The fuel line pickup screen was clear of any blockage and no foreign material was seen in the fuel tank.

The carburetor icing probability chart included in Federal Aviation Administration Special Airworthiness Information Bulletin No. CE-09-35, Carburetor Icing Prevention, indicated that the airplane was operating in an area that was associated with a serious risk of carburetor ice accumulation at glide power settings. 

History of Flight

Approach
Loss of engine power (partial) (Defining event)

Emergency descent
Off-field or emergency landing
Collision with terr/obj (non-CFIT)

Pilot Information

Certificate: Private
Age: 28
Airplane Rating(s): Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 Without Waivers/Limitations
Last FAA Medical Exam: 03/21/2017
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time:

Flight Instructor Information

Certificate: Commercial
Age: 25
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Right
Other Aircraft Rating(s): None
Restraint Used: 3-point
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s):  Airplane Multi-engine; Airplane Single-engine; Instrument Airplane
Toxicology Performed: No
Medical Certification: Class 1 Without Waivers/Limitations
Last FAA Medical Exam: 08/07/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent: 
Flight Time:  318.6 hours (Total, all aircraft), 13.6 hours (Total, this make and model)

Aircraft and Owner/Operator Information

Aircraft Manufacturer: PIPER
Registration: N7386P
Model/Series: PA 24 UNDESIGNATED
Aircraft Category: Airplane
Year of Manufacture: 1961
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 24-2567
Landing Gear Type: Retractable - Tricycle
Seats:
Date/Type of Last Inspection: 02/18/2018, 100 Hour
Certified Max Gross Wt.: 2551 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 1271.8 Hours as of last inspection
Engine Manufacturer: LYCOMING
ELT: Installed, not activated
Engine Model/Series: O-360 SER
Registered Owner: On file
Rated Power: 180 hp
Operator: On file
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KBAZ
Observation Time: 1451 CDT
Distance from Accident Site:
Direction from Accident Site:
Lowest Cloud Condition: Clear
Temperature/Dew Point: 29°C / 18°C
Lowest Ceiling: None
Visibility: 10 Miles
Wind Speed/Gusts, Direction: 15 knots, 190°
Visibility (RVR): 
Altimeter Setting: 29.83 inches Hg
Visibility (RVV):
Precipitation and Obscuration: No Precipitation
Departure Point: New Braunfels, TX (KBAZ)
Type of Flight Plan Filed:
Destination: New Braunfels, TX (KBAZ)
Type of Clearance: VFR
Departure Time:  CDT
Type of Airspace:

Airport Information

Airport: New Braunfels Regional Airport (KBAZ)
Runway Surface Type: Asphalt
Airport Elevation: 658 ft
Runway Surface Condition: Dry; Vegetation
Runway Used: 17
IFR Approach: None
Runway Length/Width: 5364 ft / 100 ft
VFR Approach/Landing: Forced Landing; Touch and Go

Wreckage and Impact Information

Crew Injuries: 2 Minor
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 Minor
Latitude, Longitude:  29.702222, -98.027222

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