Waltman Theodore J MOOSE N384JP

Summary

On 30 September 2011 at about 16:00 local time, a Waltman Theodore J MOOSE registered N384JP was involved in an accident near Hays, Kansas, United States. 4 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

30 September 2011 at 16:00

Classification

Accident

Location

Hays, Kansas, United States

Coordinates

38.8386, -99.2706

Aircraft

Waltman Theodore J MOOSE

Registration

N384JP

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Hudson → Hays

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN11CA679

Nobody was injured.

Rudder flutter due to the design changes to the airplane's horizontal stabilizer.

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

Read the full NTSB narrative

During cruise flight in smooth air, with the autopilot engaged, the experimental category amateur-built airplane suddenly encountered a single occurrence of rudder flutter that lasted 2 to 3 seconds and then ceased. One passenger described the “frequency of vibration about 10 Hz” (cycles per second) and described the sound as “BRAAP.” The pilot disengaged the autopilot and continued to his original destination for an uneventful landing. A subsequent examination of the airplane found substantial damage to the stringers, frames, and empennage skin in the area just forward of the horizontal stabilizers. The pilot, who was also the builder of the airplane, had added an electrically actuated rudder trim tab several years earlier. Most of the weight of the rudder assembly was aft of the rudder hinges, and the builder had not installed rudder counterbalance weights forward of the hinges. In addition, he had recently installed struts on the bottom of the horizontal stabilizer. Airworthiness standards for certification of normal category airplanes require that they must be shown to be free from flutter. Airworthiness standards for certification of experimental category airplanes do not require that they meet those standards.

Quoted verbatim from the NTSB record.