MESQUITE, TX, USA
N9516
BOWERS MIDGET MUSTANG M-1
The pilot had installed a composite propeller with a composite spinner that extended forward about 14 inches and did not have a forward support plate. During the first flight, an object departed the propeller area. The pilot reported the airplane rolled left with a loss of control during the forced landing. A pilot/witness reported observing the airplane stall. The spinner backing plate remained attached with the 12 screws in place; however, the rest of the spinner was not recovered. Flap continuity was confirmed. The propeller installation bolts did not extend through the self-locking nuts. The owner/pilot did not contact the FAA for an inspection of the propeller installation. FAA inspectors stated that the installation was a major change and required FAA notification. The experimental category airplane and the propeller were neither manufactured nor required to be in accordance with a FAA Type Certificate (and therefore, they are not governed by any FAR's for design and production).
On May 10, 1996, at 1307 central daylight time, a Bowers Midget Mustang M-1, N9516, operated by a private owner as a Title 14 CFR Part 91 flight, collided with terrain following a loss of control during a forced landing near Mesquite, Texas. Visual meteorological conditions prevailed for the local personal flight and a flight plan was not filed. The commercial pilot received minor injuries and the airplane was destroyed. During an interview, conducted by the investigator-in-charge, and on the Pilot/Operator report, the pilot reported the information in this paragraph. Following the preflight, taxi, and runup, the takeoff was initiated on runway 17 at the Phil L. Hudson Municipal Airport, Mesquite, Texas. During the takeoff roll, "acceleration was OK." At a climb airspeed of 90 mph and an altitude of 250 to 300 feet above the ground, there was an airplane "vibration and shudder followed by a loud cracking sound." The pilot observed "an object depart the propeller area and travel to the left side." The pilot changed the airplane pitch for 80 mph, for landing in a field south of the airport, and at 150 feet above the ground, full flaps (30 degrees) were extended. Within 2 to 3 seconds the airplane rolled left and full right aileron did not stop the left roll. The airplane impacted the ground nose low with the left bank increasing. The airplane "cartwheeled on its' wing tips and came apart." Once the airplane stopped, the pilot turned off the airplane battery switch, released the seat belt and shoulder harness, and exited forward where the instrument panel and engine had separated from the airframe. A pilot/witness, located approximately 7,000 feet from the accident site, observed the airplane depart runway 17 and begin a 10 degree banking right turn. The bank increased to 30 to 45 degrees as the airplane "appeared to be attempting to make the runway." The witness further observed that after "tightening his turn the aircraft appeared to stall and roll to a 90 degree bank [with the] wing's perpendicular to the ground." During a telephone interview, conducted by the investigator-in-charge, the pilot reported that the witness was a flight instructor. The pilot also stated that the witness was too far away to confirm a stall and that he experienced a loss of control while maneuvering for the landing; however, "he did not stall the airplane." After purchasing the airplane, the pilot flew the airplane 14 hours, prior to changing the propeller manufactured by Ivoprop. This was the first flight following the pilot's installation of the composite propeller. Instructions for installing the propeller were shipped by the manufacturer and the pilot reported following the instructions. The composite propeller components did not include the spinner. The pilot installed the previous composite spinner. The pilot stated that the spinner extended forward about 14 inches and did not have a forward support plate installed. Following the accident, the spinner backing plate remained attached to the engine; however, the rest of the spinner was not recovered. Twelve screws, that attached the spinner to the backing plate, were found in place. An FAA inspector suggested that the addition of a forward support plate might reduce the vibration of the composite spinner. During a previous inspection, the pilot had observed wear on the rear spar in the area of the flap rods. The Pilot/Operator report stated a "possible asymmetrical flap deployment" contributed to the loss of control. Flap continuity was confirmed during examination on June 7, 1996, by a Board investigator. The old propeller flange required 8 bolts; however, the composite propeller installation required 6 bolts. Ivoprop sent the pilot a modified adapter flange for the 6 bolt propeller. The investigator found that the 6 bolts securing the propeller to the adapter did not extend through the self-locking nuts. The investigator also found that the 8 bolts securing the adapter to the engine crankshaft did not extend through the self-locking nuts. The manufacturer reported shipping the 6 propeller attaching bolts, but did not provide the 8 adapter bolts. The owner/pilot stated that he used the bolts obtained with the propeller and purchased the 8 bolts for the adapter. A review of the maintenance records by the investigator-in-charge revealed July 30, 1970, as the airplane's date of manufacture with a Continental engine model O-300-A installed. Several airworthiness certificates were issued through the years and the records contained an experimental airworthiness certificate dated September 23, 1980. The airworthiness certificate indicated that operating limitations were also issued on that date; however, the limitations were not found in the maintenance records. Aircraft records indicated that a Continental engine model O-125-2 S/N 8037-8-2 with a McCauley metal propeller model 1A170-DM33357 was installed on the airframe in 1988. October 15, 1995, was the last logbook entry certifying that the aircraft and engine had been inspected and found to be airworthy. No historic data was found for the propeller spinner installed at the time of the accident. FAA regulations require that operating limitations (FAR 91.319 copy enclosed) be issued with the experimental category airworthiness certificate (FAR 21.191 and 21.193 copies enclosed). One of the required operating limitations (wording per FAA Order 8130.2C copy enclosed) states that the FAA must be notified, and their response received in writing, prior to flying the aircraft after incorporating a major change as defined by FAR 21.93 (copy enclosed) and listed in Appendix A to FAR Part 43 (copy enclosed). The owner/pilot did not contact the FAA for an inspection following the propeller installation on the airplane. FAA inspectors stated that the installation modification from an 8 bolt propeller to a 6 bolt propeller was a major change and required notification to the FAA and their evaluation of the requirements for continued airworthiness of the aircraft. Neither the airplane nor the propeller was manufactured in accordance with an FAA Type Certificate (and therefore, they are not governed by any Federal Aviation Regulations for design and production). They are not required to hold a type certificate since the airplane was being operated in the experimental category. The propeller was examined by NTSB investigators at Arlington, Texas. Propeller construction, composite materials, and damage to the component impeded the determination of pre or post impact damage. The FAA inspector, who responded to the site, reported that all components of the aircraft, except the propeller spinner, were within the wreckage distribution pathway extending beyond the departure area of the runway. The owner stated that a piece of composite material that could be a part of the spinner was found in the grass to the side of the runway at about 4,000 feet from the departure end of the runway. The NTSB investigator-in-charge conducted numerous telephone conferences with Mr. Ivo Zdarsky of Ivoprop Corporation concerning the installation of their propellers on various aircraft. Following the conferences and a letter, Mr. Zdarsky added the following statement on all propeller installation instructions shipped by Ivoprop Corporation: "IF YOUR AIRCRAFT HOLDS U.S. EXPERIMENTAL AIRWORTHINESS CERTIFICATE YOU ARE SUPPOSED TO CONTACT THE FAA FSDO BEFORE FLYING THE AIRCRAFT. WHEN NOTIFIED, THE FAA INSPECTOR CAN DETERMINE IF THE PROCEDURE WAS A MAJOR CHANGE (AS DEFINED PER FAR 21.93 AND LISTED IN APPENDIX A TO PART 43) AND IF ANY ADDITIONAL INSPECTIONS OR OPERATIONS LIMITATIONS ARE NEEDED PRIOR TO FLIGHT." The airplane was released to the owner following the investigation.
The pilot's failure to maintain aircraft control following the separation of the propeller spinner installed by the pilot. A factor was the pilot's failure to obtain the required FAA inspection for the installation.
Source: NTSB Aviation Accident Database
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