Schweizer 269C-1 N152CC

Summary

On 17 June 2014 at about 16:05 local time, a Schweizer 269C-1 registered N152CC, operated by Ace Pilot Training, was involved in an accident near Allentown, Pennsylvania, United States. One person was on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

17 June 2014 at 16:05

Classification

Accident

Location

Allentown, Pennsylvania, United States

Nearest airport

Lehigh Valley International (ABE)

Coordinates

40.6522, -75.4406

Aircraft

Schweizer 269C-1

Registration

N152CC

Category

Helicopter

Year built

2002

Operator

Ace Pilot Training

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Allentown → Allentown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ERA14LA293

1 person had minor injuries.

Inadequate inspection and maintenance of the helicopter’s landing gear dampers, which resulted in ground resonance during helicopter shutdown.

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

Read the full NTSB narrative

The student pilot landed the helicopter after a 40-minute flight and started the engine shut down procedures. She stated that she applied the collective friction and started the timer, running the engine at 2,500 rpm for a cool-down period. She turned off the fuel boost pump and radios and referred to the checklist to ensure she had completed the proper items. She then engaged the collective friction and was tightening the cyclic friction at the cyclic base when the helicopter developed ground resonance. The student pilot could not get the helicopter airborne with the collective friction engaged, so she rolled the throttle to idle. The resonance continued to increase and, "in a matter of seconds, the helicopter shook itself apart." The helicopter had four poppet-type, nitrogen-charged hydraulic units (dampers) in the landing gear assembly to reduce landing shock and help prevent ground resonance. The four dampers were removed from the helicopter and pressure tested; all four failed to meet manufacturer's specifications. Without the airframe protection provided by the dampers, oscillations occurred that resulted in the helicopter rocking on its landing gear and the tailboom twisting toward the right side of the helicopter where it joined the main structure. Maintenance instructions noted that the landing gear dampers would experience a decrease in pressure with helicopter usage and required that they be extension-checked during each 100-hour inspection or every 6 months, whichever occurred first. The helicopter's most recent 100-hour inspection occurred about 2 months before the accident, and it had been operated 58 hours since the inspection. Review of maintenance records for the most recent 100-hour inspection and about 800 flight hours before the accident revealed no mention of any maintenance actions involving the dampers.

Quoted verbatim from the NTSB record.