MIA08LA196

NTSB accident investigation · Cessna 120 · Jesup, GA · September 19, 2008

Accident · No injuriesLimited investigationFinal report
Date
September 19, 2008, 11:00 local (15:00 UTC)
Place
Jesup, GA
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N77068Cessna 120
Defining event
Enroute-cruise: Powerplant sys/comp malf/fail
Weather
Visual (VMC) · Day
Status
Completed · report June 17, 2010
Report
Approved by Office Director
Parties
FAA/FSDO
FAA report
20080919849859A
Case key
68959

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

An oil starvation-induced catastrophic engine failure due to the improper installation of the crankshaft expansion plug during engine overhaul.

Findings · 3

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Maintenance: installationPersonnel issues › Task performance · Maintenance personnelCessna 120: 2 casesAll aircraft: 371 casesProbable cause
Engine (reciprocating): recip eng front sectionAircraft › Aircraft power plant · Incorrect service/maintenanceCessna 120: 1 caseAll aircraft: 13 casesProbable cause
Engine (reciprocating): recip eng oil sysAircraft › Aircraft power plant · MalfunctionCessna 120: 1 caseAll aircraft: 130 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

The pilot stated that they were about 1 hour and 20 minutes into their planned 2-hour cross country flight, when an opaque film began to accumulate on the airplane’s windshield. Engine oil was observed leaking from the forward right engine cowling area. Within a minute, forward visibility was severely restricted and the pilot had to rely on the instruments for level flight while referring out the side window for visual reference. There were no abnormal indications from the engine instrumentations. The nearest airport was too far away so the pilot elected to land in a clear field within gliding distance. The pilot approached the open field in a slip; the windshield was covered with oil. He lost visual reference as he recovered from the slip to land, and had to estimate the flare for the touchdown. The airplane landed hard and bounced, which separated the right wheel assembly from the gear. The airplane’s right gear dug in on the second contact with the ground, resulting in the airplane coming to an abrupt stop in a nose-low and tail-high position. A wreckage examination revealed the engine oil was leaking from the front section of the engine crankcase, behind the propeller flange. The forward crankshaft expansion plug was observed dislodged from it seating, allowing pressurized oil to escape from the forward end of the crankshaft. The airplane’s engine had been overhauled 39 flight hours prior to the accident.

Factual narrative

On September 19, 2008, at 1100 eastern daylight time, a Cessna 120, N77068, incurred substantial damage during a force landing in an open field near Jesup, Georgia. Visual meteorological conditions prevailed and a flight plan was filed for the Title 14 Code of Federal Regulations Part 91, personal flight. The pilot and the passenger were not injured. The pilot stated that he planned a flight from the Macon Downtown Airport, Macon, Georgia to the Jekyll Island Airport, Jekyll Island, Georgia. They departed at about 0945. The flight went uneventful for the first hour of the estimated 2 hour flight. About an hour and twenty minutes into the flight, an opaque film began to accumulate on the windshield. Engine oil was leaking from the forward right engine cowling area. Within a minute, forward visibility was severely restricted and he had to rely on the instruments for level flight while referring out the side window for visual reference. There were no abnormal indications from the engine instrumentations. The nearest airport was too far away and the pilot elected to land in a clear field within gliding distance. The pilot approached the open field in a slip; the windshield was covered with oil. He lost visual reference as he recovered from the slip to land; estimating the flare for the touchdown. The airplane landed hard and bounced, which separated the right wheel assembly from the gear. The airplane’s right gear dug in on the second contact with the ground, resulting in the airplane coming to an abrupt stop in a nose low and tail high position. The pilot and passenger removed their four point restraint system and exited the airplane on their own. A wreckage examination a Federal Aviation Administration inspector revealed the engine oil was leaking from the front section of the engine crankcase, behind the propeller flange. Upon removal of the propeller and spinner, the forward crankshaft expansion plug was observed dislodged from it seating, allowing pressurized oil to escape from the forward end of the crankshaft. The pilot/owner stated the airplane’s engine was overhauled 39 flight hours prior to the accident.

Aircraft

Registration
N77068
Reported as
Cessna 120
Category
Airplane
Serial number
11522
Airframe hours
2,496
Engine
Lycoming O-290-D, 125 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Operator
Virgil P. Warren,III
Registered owner
Virgil P. Warren,III
Airworthiness certificate
Standard, Normal
Last inspection
Annual · July 16, 2008 · 12 hours before
Departed
MAC · Macon, GA
Destination
09J · Jekyll Island, GA
Flight plan
VFR

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
59
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, With waivers/limitations
Seat
Left
Flight hours
152 total · 87 in this make and model · 59 as pilot in command · 13 in the last 90 days · 8 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
360° at 9 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
75 °F, dew point 57 °F
Altimeter
30.14 inHg
Observed at
LHW, 15 nm away

Docket · 5

The files NTSB released with the investigation on April 13, 2010, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.2 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.