CEN12LA299

NTSB accident investigation · Piper PA-24-250 · Shawnee, OK · May 14, 2012

Accident · No injuriesLimited investigationFinal report
Date
May 14, 2012, 13:30 local (18:30 UTC)
Place
Shawnee, OK
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N7171PPiper PA-24-250
Defining event
Maneuvering: Loss of engine power (partial)
Weather
Visual (VMC) · Day
Status
Completed · report July 18, 2012
Report
Approved by Office Director
NTSB office
Central Region
Parties
FAA Flight Standards District Office
FAA report
20120514012489A
Case key
83645

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

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Probable cause

The improper installation of the mixture cable by maintenance personnel, which allowed the mixture cable to entangle with the landing gear during gear extension and led to the subsequent loss of engine power.

Findings · 2

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.

Engine controls: mixture controlAircraft › Aircraft power plant · Incorrect service/maintenancePiper PA-24-250: 1 caseAll aircraft: 41 casesProbable cause
Maintenance: installationPersonnel issues › Task performance · Maintenance personnelPiper PA-24-250: 2 casesAll aircraft: 371 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 was conducting the second leg of the airplane’s first flight after a recent engine overhaul. On final approach, the pilot lowered the landing gear handle; however, he did not receive confirmation that the landing gear was down. The pilot stated that he applied a lot of force to conduct the manual gear override but that he was not able to get the handle up. Shortly thereafter, the engine lost power. The airplane was substantially damaged during the subsequent forced landing. A postaccident examination of the airplane revealed that the mixture cable was bent, the cable was pulled from its last clamp prior to the carburetor mixture control, and the mixture control was pulled into the cutoff position. The routing of the mixture cable did not match assembly drawings, and several clamps used to route the mixture cable were missing. A grease fitting on the over-center link for the nose landing gear was in line with the bend in the mixture cable. Most likely, the landing gear center link became entangled in the mixture control cable, which prevented the nose landing gear from extending. The mixture likely came to idle when the pilot used extra force to try to extend the landing gear. The mixture cable was not installed properly during the recent engine overhaul.

Factual narrative

On May 14, 2012, approximately 1330 central daylight time, a Piper PA-24-250 airplane, N7171P, was substantially damaged during a forced landing to a field near Shawnee, Oklahoma. The private pilot was not injured. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a ferry flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight originated from Sundance Airpark (KHSD), Oklahoma City, Oklahoma, approximately 1315, and was en route to Shawnee Regional Airport (KSNL), Shawnee, Oklahoma. On final approach, the pilot lowered the landing gear handle; however, he did not receive confirmation that the landing gear was down and locked. The pilot stated that "a lot of force" was required to conduct the manual gear override, but he was not able to get the handle up. Shortly thereafter, the engine lost power. The pilot performed a gear up, forced landing to a field. During the landing, the right wing was buckled and the firewall was wrinkled. According to the Federal Aviation Administration inspector who traveled to the scene, the mixture cable was bent and would not move. The routing of the mixture cable did not match assembly drawings. The mixture cable was found separated from its last clamp prior to the carburetor mixture control and the mixture control was found in the cutoff position. He also noted that several clamps normally used to route the mixture cable were not present. A grease fitting on the over center link for the nose landing gear was in line with the bend in the mixture cable. According to the pilot, the engine had just been removed and reinstalled for an engine overhaul.

Aircraft

Registration
N7171P
Reported as
Piper PA-24-250
Category
Airplane
Serial number
24-2339
Airframe hours
5,222
Engine
Lycoming O-540 SERIES, 250 horsepower, reciprocating
Damage
Substantial damage
Flight
Ferry · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
Annual · September 25, 2011
Departed
KHSD · Oklahoma City, OK
Destination
KSNL · Shawnee, OK

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
56
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Instrument ratings
Airplane
Medical
Class 3, With waivers/limitations
Last flight review
November 28, 2010
Seat
Left
Flight hours
1,156 total · 356 in this make and model · 1,004 as pilot in command · 1 in the last 90 days · 1 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
40° at 6 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
73 °F, dew point 54 °F
Altimeter
30.15 inHg
Observed at
KSNL, 1 nm away

Docket · 4

The files NTSB released with the investigation on June 5, 2012, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.3 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.