Cessna 152 N4886B

Summary

On 17 December 2018 at about 17:10 local time, a Cessna 152 registered N4886B, operated by Orange Wings Aviation Academy, was involved in an accident near Bell Glade, Florida, United States. 2 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

17 December 2018 at 17:10

Classification

Accident

Location

Bell Glade, Florida, United States

Coordinates

26.4511, -80.5378

Aircraft

Cessna 152

Registration

N4886B

Category

Airplane

Year built

1979

Engines

1

Operator

Orange Wings Aviation Academy

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Lakeland → Pompano Beach

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ERA19LA069

Nobody was injured.

A partial loss of engine power due to the No. 1 cylinder's valve keeper becoming dislodged, which ultimately resulted in the intake valve becoming stuck in the valve guide and in the loss of compression to the cylinder.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The private pilot reported that, while conducting a personal, cross-country flight and descending from cruise level, the engine began gradually losing power, so he applied carburetor heat, which initially restored cruise power. Several minutes later, the engine again lost partial power and began to vibrate. The engine continued to lose power, and the airplane was unable to maintain altitude. The pilot chose to execute a forced landing on a field, during which the nosewheel dug into the ground, and the airplane subsequently nosed over.   Examination of the engine revealed that the No. 1 intake valve was stuck in the valve guide and that the upper valve spring seat on the No. 1 cylinder was broken. Detailed examination revealed contact marks on the interior and end faces of the valve keeper and pitting and radial cracks in the intake valve head. The valve springs' strength was found to be within serviceable limits. The rocker arm contact wear pattern on the valve tip was abnormal. It is likely that, during operation, the intake valve keeper was dislodged and then became wedged in the valve spring seat until the valve spring seat fractured, at which time the intake valve became stuck in the valve guide. This resulted in a loss of compression to that cylinder and the subsequent partial loss of engine power. The contact marks on the interior and end faces of the valve keeper indicate that the keeper had been dislodged for some time while the engine operated and that the valve spring seat was intact. The pitting and radial cracks in the intake valve head indicate that the engine was operated while the valve was not seating properly, which is also consistent with operation with a dislodged valve keeper. The lack of a normal rocker arm contact wear pattern on the valve tip indicates that the valve keeper likely became dislodged soon after the valve was placed into service. The engine manufacturer's Operator's Manual recommended periodic inspections (every 400 flight hours) of the intake valve. During a review of the engine maintenance records, no records were found indicating whether the periodic valve inspections were completed. If these inspections had been completed, the abnormal wear pattern on the valve and the dislodged valve keeper would likely have been detected.

Quoted verbatim from the NTSB record.