RENO, NV - While the report on the deadly crash of the Galloping Ghost at the National Championship Air Races is heavily anticipated today, a KOLO-TV investigation into recent NTSB accident reports finds numerous problems with older and experimental planes while engaged in racing activities at the Reno-Stead airport. In at least two of the cases, planes saw a problem that could have affected their ability to control the direction of the aircraft, and one that would have had the plane shoot up into the air like the Galloping Ghost did.
The most recent fatality prior to last week is eerily similar the tragedy with the Galloping Ghost in which the "trim tab" was a central focus of the investigation. Investigators found that a modification of the trim tab system would have created extreme upward g-forces. That is the same factor that may have played a roll in the Galloping Ghost tragedy.
Here is what investigators found that offers some insight into what may be an impending danger with modified aircraft.
It was back on September 6, 2008 during an air race class qualification flight of an experimental and armature-built "Debus J / Mountain S / Bowes E DEBUS-CASST-SNOSHOO." The pilot was performing a series of maneuvers required to obtain a class license for the race. During a required roll maneuver, as the airplane got half-way around the roll at a speed of about 220 miles per hour when both wings fell off the plane.
When investigators looked into this fatal accident, they found that the amateur built experimental airplane was fitted with an in-flight adjustable pitch trim system, which was a deviation from the original ground-only trim adjustment design. The trim system, designed by the airplane's builder, allowed the pilot to adjust the pitch trim by moving the horizontal stabilizer while in flight.
The in-flight system included a lever attached to the fuselage structure, and its movement was restricted with friction washers between the fuselage and the lever. Full travel of the lever resulted in one inch of vertical movement of the horizontal stabilizer's leading edge. The manufacturer of the airframe kit said that the trim system installed on the accident airplane was not of their design.
They also said that any movement of the horizontal stabilizer during an abrupt maneuver could produce an extremely high amount of G-forces and possibly exceed the structural design limits of the airplane.
After the accident, investigators looked at the wreckage and couldn't find any other pre-existing anomalies with the airframe or flight control system. When they looked at the cracks in the wings, they found the fractures in both wings were consistent with a "substantial upward force" and overload.
Since the pilot died, they don't know if the pilot moved the horizontal trim system while in-flight. Amateur built airplanes with experimental certificates are not subject to the airworthiness standards in 14 CFR Parts 23 and 47 of the Federal Aviation Regulations, and builders and owners are free to make any modifications to the airplane at will.
So, that was the cause according to the NTSB: The movement of the airplane’s modified horizontal stabilizer trim system during an intentional high speed aerobatic maneuver. The force exceeded the stress limits of the airplane that was so strong, it broke off the wings. Contributing to the accident was that the builder’s deviation from the airplane designer's original trim system.
Videos prior to the Galloping Ghost accident show problems with the planes trim tab and the plane experiencing serious force as it shot straight up into the air.
There was a third steering problem with less serious consequences this year too. On June 18, 2011 at about 2:50 PM an "Aerovodochody L-29 Delfin, N37KF," was in a race pattern at the Reno Stead Airport when it had a sudden partial failure of the primary airframe structure supporting the airplane's rudder.
A commercial pilot was at the yoke and was the only person on board. That pilot was not hurt, but according to the NTSB report, the airplane, which was owned and operated by Ward Raju Mann, sustained substantial damage.
It was during air race qualification/training flight and happened just 15 minutes after the plane took off. According to the Federal Aviation Administration (FAA) inspector who responded to the scene, while the airplane was in flight, part of the structure associated with an engine failed. That failure allowed jet blast from the engine to be deflected onto a portion of the primary airframe structure.
The melting of the airframe affected the support and movement of the airplane's rudder. Although the failure occurred in flight, it was not detected until the pilot was operating the rudder pedals after landing.
You may remember a dramatic crash just about a year ago. On September 19, 2010 at 4 in the evening, an experimental Giboney Thunder Mustang, N151G, touched its wing into the dirt and cartwheeled across the desert during landing at Reno/Stead Airport, Reno, Nevada. The plane was destroyed, and amazingly the pilot survived.
This one happened during the actual air races. The pilot was on the last lap of an air race when he reported a loss of engine power. During the forced landing, the airplane bounced and subsequently cartwheeled into the dirt next to the runway.
The pilot saw that the engine begin to overheat during the race in high winds. He elected to perform a precautionary landing, but the engine stopped producing power and the airplane began to rapidly loose altitude according to the NTSB.
Investigators dug through the debris and found a portion of a connecting rod. When they looked at that and the engine casing, they found a hole in the crankcase above the number 1 and 2 cylinders. The connecting rod for the No. 2 cylinder was fractured and separated below the piston wrist pin; the piston end rotated freely and the crankshaft end was fractured. That failure and resulting temperatures was the cause of that crash according to the NTSB. Amazingly the pilot only sustained minor injuries.