Saturday, December 04, 2021

Loss of Control in Flight: Cessna 172R Skyhawk, N996RA; accident occurred July 10, 2021 at Petaluma Municipal Airport (O69), Sonoma County, California

Aviation Accident Final Report - National Transportation Safety Board
The National Transportation Safety Board did not travel to the scene of this accident. 

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

Investigation Docket - National Transportation Safety Board:

Christiansen Aviation Inc

San Carlos Flight Center

Location: Petaluma, California
Accident Number: WPR21LA269
Date and Time: July 10, 2021, 12:17 Local
Registration: N996RA
Aircraft: Cessna 172R 
Aircraft Damage: Substantial
Defining Event: Loss of control in flight
Injuries: 4 None
Flight Conducted Under: Part 91: General aviation - Personal


The pilot reported that, about 20 minutes into the cross-country flight, the airplane experienced a partial electrical failure which caused the intercom, radio, transponder, flaps, and some engine instruments to go offline, although the voltmeter and ammeter were still showing normal readings.

The pilot cycled both the master and avionics master switches, with no improvement, and decided to divert to the nearest untowered airport. During the descent and approach, he became distracted multiple times as he heard intermittent short "blips" from the intercom.

The pilot entered a right downwind entry into the traffic pattern and planned for a no-flap landing. He overshot to the right of the runway centerline as they turned from the base to final leg. He was able to maneuver to rejoin the centerline by the time they reached short final. They passed over the runway threshold with a left crosswind, and as the pilot initiated the flare, he felt the airplane sink aggressively, and he realized that he had initiated the flare too high. The airplane drifted to the right of the runway surface and landed hard in the grass in a nose high attitude. The lower fuselage and wing strut was substantially damaged. The pilot reported that an on-airport mechanic examined the airplane after the accident and was not able to find any issues with the electrical system.

The pilot reported that, he had significant astigmatism and myopia, and used contact lenses for all previous flights, however the accident flight was the first time he had flown with eyeglasses after experiencing a contact lens malfunction that morning. He also reported that although he had performed multiple no-flap landings in the past, the accompanying change in forward visibility over the nose in concert with the use of eyeglasses instead of contact lenses, resulted in a changed sight picture and reduced peripheral vision. 

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot’s improper landing flare which resulted in a hard landing following a partial loss of electrical power. Contributing to the accident was the pilot’s distraction and hampered visual function.


Personnel issues Decision making/judgment - Pilot
Personnel issues Aircraft control - Pilot
Aircraft Landing flare - Not attained/maintained
Aircraft (general) - Malfunction
Personnel issues Visual function - Pilot
Personnel issues Stress - Pilot

Factual Information

History of Flight

Enroute-climb to cruise Electrical system malf/failure
Landing-flare/touchdown Loss of control in flight (Defining event)
Landing Hard landing

Pilot Information

Certificate: Private 
Age: 28, Male
Airplane Rating(s): Single-engine land 
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used: 3-point
Instrument Rating(s): None 
Second Pilot Present:
Instructor Rating(s): None 
Toxicology Performed:
Medical Certification: Class 3 With waivers/limitations 
Last FAA Medical Exam: October 11, 2019
Occupational Pilot: No 
Last Flight Review or Equivalent: March 6, 2021
Flight Time: 127 hours (Total, all aircraft), 15 hours (Total, this make and model), 47 hours (Pilot In Command, all aircraft), 20 hours (Last 90 days, all aircraft), 7 hours (Last 30 days, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: Cessna
Registration: N996RA
Model/Series: 172R 
Aircraft Category: Airplane
Year of Manufacture: 1998 
Amateur Built:
Airworthiness Certificate: Commuter; Utility 
Serial Number: 17280404
Landing Gear Type: 
Tandem Seats: 4
Date/Type of Last Inspection: May 26, 2021 Annual
Certified Max Gross Wt.: 2457 lbs
Time Since Last Inspection: 67.8 Hrs
Engines: 1 Reciprocating
Airframe Total Time: 8569.3 Hrs as of last inspection
Engine Manufacturer: Lycoming
ELT: C91A installed, not activated
Engine Model/Series: IO-360-L2A
Registered Owner: 
Rated Power: 180 Horsepower
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual (VMC) 
Condition of Light: Day
Observation Facility, Elevation: KO69,89 ft msl 
Distance from Accident Site: 1 Nautical Miles
Observation Time: 11:55 Local
Direction from Accident Site: 152°
Lowest Cloud Condition: Clear 
Visibility: 10 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 4 knots / 
Turbulence Type Forecast/Actual:  /
Wind Direction: 280°
Turbulence Severity Forecast/Actual:  /
Altimeter Setting: 29.93 inches Hg
Temperature/Dew Point: 30°C / 11°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: San Carlos, CA (KSQL) 
Type of Flight Plan Filed: None
Destination: Shelter Cove, CA (0Q5)
Type of Clearance: VFR flight following; None
Departure Time: 11:11 Local 
Type of Airspace: Class G

Airport Information

Runway Surface Type: Asphalt
Airport Elevation: 90 ft msl
Runway Surface Condition: Dry
Runway Used: 11/29
IFR Approach: None
Runway Length/Width: 3600 ft / 75 ft
VFR Approach/Landing: Precautionary landing

Wreckage and Impact Information

Crew Injuries: 1 None 
Aircraft Damage: Substantial
Passenger Injuries: 3 None 
Aircraft Fire: None
Ground Injuries: 
Aircraft Explosion: None
Total Injuries: 4 None 
Latitude, Longitude: 38.255757,-122.6013

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