Tuesday, May 23, 2017

Cessna 150J, N60579: Accident occurred May 21, 2017 in Zepp, Shenandoah County, Virginia

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Baltimore, Maryland

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


Location: Zepp, VA
Accident Number: GAA17CA306
Date & Time: 05/21/2017, 0945 EDT
Registration: N60579
Aircraft: CESSNA 150
Aircraft Damage: Substantial
Defining Event: Loss of engine power (partial)
Injuries: 1 Minor, 1 None
Flight Conducted Under: Part 91: General Aviation - Instructional 


The flight instructor reported that, during a long cross-country flight, they encountered deteriorating weather conditions, and to remain visual flight rules, he altered course and destination. En route and while approaching a ridge line, he "noticed that [the airplane's] airspeed started to drop toward 65 miles an hour." He added that "[he] thought that maybe [the airplane was] picking up carburetor ice and [he] reached for the carburetor heat and pulled it out."

The student pilot reported that, after the flight instructor stated, "watch your airspeed," he looked at the rpm gauge and noted that it was indicating 1,800 to 1,900 rpm. He added that the flight instructor took over the flight controls and that the airplane then impacted the top of a ridge.

The airplane sustained substantial damage to the right wing.

Atmospheric conditions reported at the time of the accident around the accident site were conducive to serious icing at cruise power. It is likely that carburetor ice accumulated due to the student pilot's failure to apply carburetor heat and the flight instructor's delayed application of carburetor heat, which resulted in a partial loss of engine power.

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 due to the formation of carburetor icing, which resulted from the student pilot's failure to apply carburetor heat and the flight instructor's delayed response in applying carburetor heat while operating in conditions conducive to carburetor icing.


Intake anti-ice, deice - Not used/operated (Cause)

Personnel issues
Use of equip/system - Instructor/check pilot (Cause)
Delayed action - Student pilot (Cause)
Delayed action - Instructor/check pilot (Cause)
Lack of action - Student pilot (Cause)

Environmental issues
Conducive to carburetor icing - Effect on operation (Cause)

Factual Information

History of Flight

Other weather encounter
Loss of engine power (partial) (Defining event)


Controlled flight into terr/obj (CFIT)

Flight Instructor Information

Certificate: Airline Transport; Flight Instructor
Age: 71, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Right
Other Aircraft Rating(s): None
Restraint Used: 4-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 3 With Waivers/Limitations
Last FAA Medical Exam: 09/21/2016
Occupational Pilot: Yes
Last Flight Review or Equivalent: 08/01/2016
Flight Time: (Estimated) 28250 hours (Total, all aircraft), 70 hours (Total, this make and model), 26750 hours (Pilot In Command, all aircraft), 41.8 hours (Last 90 days, all aircraft), 8.8 hours (Last 30 days, all aircraft), 3.7 hours (Last 24 hours, all aircraft) 

Student Pilot Information

Certificate: Student
Age: 28, Male
Airplane Rating(s): None
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used: Unknown
Instrument Rating(s): None
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 Without Waivers/Limitations
Last FAA Medical Exam: 01/30/2017
Occupational Pilot: No
Last Flight Review or Equivalent: 
Flight Time: (Estimated) 31.6 hours (Total, all aircraft), 31.6 hours (Total, this make and model), 14 hours (Pilot In Command, all aircraft), 14.2 hours (Last 90 days, all aircraft), 6 hours (Last 30 days, all aircraft), 3.7 hours (Last 24 hours, all aircraft) 

Aircraft and Owner/Operator Information

Aircraft Manufacturer: CESSNA
Registration: N60579
Model/Series: 150 J
Aircraft Category: Airplane
Year of Manufacture: 1969
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 15070419
Landing Gear Type: Tricycle
Seats: 2
Date/Type of Last Inspection: 04/14/2017, Annual
Certified Max Gross Wt.: 1600 lbs
Time Since Last Inspection: 
Engines: 1 Reciprocating
Airframe Total Time: 3972 Hours
Engine Manufacturer: CONT MOTOR
ELT: Installed, not activated
Engine Model/Series: O-200
Registered Owner: On file
Rated Power: 100 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: KOKV, 727 ft msl
Observation Time: 1335 UTC
Distance from Accident Site: 20 Nautical Miles
Direction from Accident Site: 72°
Lowest Cloud Condition: 
Temperature/Dew Point: 13°C / 6°C
Lowest Ceiling: Overcast / 3300 ft agl
Visibility:  10 Miles
Wind Speed/Gusts, Direction: 5 knots, 120°
Visibility (RVR): 
Altimeter Setting: 30.3 inches Hg
Visibility (RVV): 
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: CUMBERLAND, WV (CBE)
Type of Flight Plan Filed: None
Destination: NEW MARKET, VA (8W2)
Type of Clearance: None
Departure Time: 0900 EDT
Type of Airspace: Class G

Wreckage and Impact Information

Crew Injuries: 1 Minor, 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 Minor, 1 None
Latitude, Longitude: 39.039722, -78.555833 (est)

Preventing Similar Accidents  

Preventing Carburetor Icing

Accidents involving carburetor ice stem from pilots not recognizing when weather conditions are favorable to carburetor icing and inaccurately believing that carburetor icing is only a cold- or wet-weather problem. Pilots also may not use the carburetor heat according the aircraft's approved procedures to prevent carburetor ice formation. Carburetor icing accidents can occur when pilots do not recognize and promptly act upon the signs of carburetor icing.

Be sure to check the temperature and dew point to determine whether the conditions are favorable for carburetor icing. Remember, serious carburetor icing can occur in ambient temperatures as high as 90° F or in relative humidity conditions as low as 35 percent at glide power. Consider installing a carburetor temperature gauge, if available.

Refer to the approved aircraft flight manual or operating handbook to ensure that carburetor heat is used according to the approved procedures and properly perform the following actions: 1) Check the functionality of the carburetor heat before flight. 2) Use carburetor heat to prevent the formation of carburetor ice when operating in conditions and at power settings in which carburetor icing is probable. Remember, ground idling or taxiing time can allow carburetor ice to accumulate before takeoff. 3) Immediately apply carburetor heat at the first sign of carburetor icing, which typically includes a drop in rpm or manifold pressure (depending upon how your airplane is equipped). Engine roughness may follow.

Engines that run on automobile gas may be more susceptible to carburetor icing than engines that run on Avgas.

See http://www.ntsb.gov/safety/safety-alerts/documents/SA_029.pdf for additional resources.

The NTSB presents this information to prevent recurrence of similar accidents. Note that this should not be considered guidance from the regulator, nor does this supersede existing FAA Regulations (FARs).

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