Frederick F 1 N158CF

Summary

On 14 September 2012 at about 19:19 local time, a Frederick F 1 registered N158CF was involved in an accident near Reno, Nevada, United States. One person was 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

14 September 2012 at 19:19

Classification

Accident

Location

Reno, Nevada, United States

Nearest airport

Reno Stead (RTS)

Coordinates

39.6681, -119.5486

Aircraft

Frederick F 1

Registration

N158CF

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Air Race/Show

Phase of flight

Not recorded

Route

Reno → Reno

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR12FA421

Nobody was injured.

The pilot’s operation of the airplane above the established never-exceed speed and the incorrect installation of the trim tab control horn, which resulted in the flutter of the left elevator trim tab.

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

Read the full NTSB narrative

The accident airplane was participating in an air race, and, when the airplane was at 180 knots indicated airspeed (KIAS), the pace airplane released the flight of airplanes to enter the race course. The pilot reported that, shortly after, a "vibration" began at an unknown airspeed and that it then increased to a heavy flutter event. The pilot pitched the airplane upward and reduced the airspeed. As the airspeed decreased below 90 KIAS, the vibration stopped, and the pilot landed uneventfully. Postaccident examination of the control horn assembly revealed fractures at the forward and aft trim tab control horn brackets and the rod end clevis. According to the airplane manufacturer's assembly manual, the aft trim tab control horn was supposed to be attached to the lower skin with four rivets. However, examination revealed that only three of the four rivets were installed; no evidence of a through hole for the fourth rivet was found. The lack of the fourth rivet allowed the aft bracket to flex, and the relative movement between the bracket and the trim tab skin during flight resulted in fretting damage. Examination of the aft bracket's fracture surface revealed features consistent with an overstress separation. The published never-exceed speed for the airplane was 240 knots true airspeed (KTAS). The airspeed was calculated to be 266 KTAS at the time of the event. The airplane's excessive speed coupled with the incorrect installation of the trim tab control horn likely initiated the flutter in the left elevator trim tab during the start of the air race. The flutter subsequently produced dynamic loads in the trim tab control system that exceeded the material strength of the system components and led to the fracture of the forward and aft trim tab control horn brackets and the rod end clevis before the airplane was slowed sufficiently to stop the flutter.

Quoted verbatim from the NTSB record.