N125TKDassault-Breguet FALCON 50 · 1994

On March 9, 2014, about 1430 eastern daylight time, an experimental amateur-built Van's RV-9A, N125TK, was substantially damaged when it nosed over while landing on a private airstrip in Live Oak, Florida. The private pilot and the pilot-rated passenger were seriously injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the personal flight that departed Suwannee Bell Airport (9FL0), Live Oak, Florida, and was conducted under the provisions of 14 Code of Federal Regulations Part 91.

According to the pilot's written statement, while landing at his home airstrip, "the main gear was put on and pilot felt nosewheel shake." The pilot then pulled back on the stick to relieve nosewheel pressure. "Nosewheel failed and folded up under engine mount causing aircraft to dig into ground while moving forward. Aircraft flipped over nose on its back."

According to the responding Federal Aviation Administration (FAA) inspector's summary of interview, the pilot stated that he and passenger flew for about 30 minutes to visit friends and remained about 30 minutes on the ground before returning home. During the outbound flight and the return leg, all seemed "normal" until the airplane crossed the fence for landing. The pilot then told the passenger, "I'm coming in too hot," but continued with the landing [to the wet turf runway.] The airplane touched down on the main landing gear first with the stick full aft, and "the nose seemed to drop hard and fast." Except for seeing the tail as the airplane nosed over, the rest happened so quickly that the pilot next remembered being upside down. Shortly thereafter, the pilot heard someone outside the airplane talking, the wing was lifted up, and the pilot was able to squeeze out.

The FAA inspector also noted that that the passenger concurred that the flight was "normal" until just before landing, when the pilot stated, "I think I'm coming in too hot." Before the passenger knew it, the airplane hit the ground hard and he must have passed out. When he came to, he was upside down pinned between the airplane and the ground, "feeling a crushing pressure and just barely able to breathe." The passenger remained in that position for about 45 minutes until responders could remove him from the wreckage.

A witness, who was driving by the airstrip when the airplane crossed in front of him for landing, stated that he stopped his vehicle to watch. Although the airstrip was somewhat higher than the road, the witness saw the airplane hit the ground "upright," and bounce. When it came back down, "it was if the plane tripped and it went nose down. The tail went straight up and over the nose and then it went out of view." The witness responded to the scene to help, and at one point, heard the pilot state that the airplane "stalled." The witness further noted that "the initial contact with the ground seemed to be very hard, and the plane seemed to bounce hard."

According to a sheriff's office report, the pilot told the responding officer that "he just lost it, and was not sure what happened."

Photographs provided by the responding Federal Aviation Administration (FAA) inspector revealed furrows in the wet turf, consistent with the location of the airplane's landing gear, with a deeper farrow in the position of the nose landing gear. The furrows led to where the airplane came to rest upside down.

Another photograph showed the collapsed nose landing gear. The wheel fairing (shell) had mud stains on it, both on the top and the bottom. The stains on the bottom half were angled upward, aft-to-forward, 15 to 20 degrees from the bottom of the fairing, consistent with an airplane nose-down attitude at ground impact.

The NTSB previously published a Structures Study in response to case number ANC05LA013, where another RV-9A (the "A" denoted tricycle landing gear) nosed over during landing.The Study examined data for 18 accidents and one incident in which Van's Aircraft series RV-6A, RV-7A, RV-8A, or RV-9A. "Several involved hard landings such as hard touchdowns, bounced landings (six), or landing in a slip. Several others involved off-field landings in rough terrain, hitting a ditch, or going down an embankment. Four of the accidents and one incident involved a touchdown and the start of a rollout on an unpaved runway, followed by the nose gear folding back. The airplanes would then slide for varying distances before nosing over. Staff also examined data for four additional incidents in which the nose gear collapse during taxi but the airplane did not nose over. These nine accidents and incidents occurred on various unpaved surfaces including gravel, turf, soft turf, hard surface with "washboard" bumps, and slight depressions. These nine cases involve the nose gear fork digging into the ground and the nose gear bending aft."

The Study further noted that of the five cases noted above, the nose gear forks exhibited evidence of contact with the ground, with grass and soil found imbedded in the fork. The propeller spinners were found to be compressed aft, and the engine inlets were undisturbed. The nose gear struts just above the fork had a smooth radius in the aft direction, and in some cases, there was a sharper bend near the strut-to-engine mount attachment point. "Additionally, in some of the cases, the paint was worn off of the front of the strut, about 9 to 15 inches above the fork. Consistent with the worn paint, there was a long, narrow furrow through the ground or grass with a soil disruption at the end of the narrow ground scar. In all of these cases, the airplane was found inverted a short distance beyond the ground scar."

The Study also indicated that a number of factors or combinations of factors could lead to the loss of ground clearance for the nose gear strut and fork. Factors might include hard landings, bounced landings, landing in a slip, low tire pressure, heavier than designed engine/propeller combinations, soft ground, heavy braking, high grass, undulating ground, and depressions in or objects on the runway.

In a service letter dated November 9, 2007, the kit manufacturer noted a March 2005 service letter describing the development and revisions made to the nose gear legs used on all two-place, tricycle landing gear RVs. The service letter described the most recent revisions in the nose gear leg design; a shortened gear leg axle and shorter fork. It also noted that the newer version of the nose gear leg and fork was shipped as standard components in Van's kits since February, 2005. "As of October, 2007, there have been no reported nose gear incidents involving this combination of leg and fork."

Also on November 9, 2007, the kit manufacturer issued a Mandatory Service Bulletin (SB) that encompassed nose gear leg and fork upgrades. The SB included all two-place, tricycle landing gear RV models with finish kits shipped prior to February, 2005. The required action was to upgrade the nose landing gear leg and fork to current configuration, to be complied with at or before the next annual condition inspection.

The accident pilot was the third owner of the airplane. The builder of the airplane noted that at the time of the build, the SB was not in effect. The builder of the airplane subsequently sold it, and when the SB came out, the next owner advised the builder that he was going to incorporate the SB, but it was unknown to the builder if it was ever done. The pilot stated that when he purchased the airplane from the second owner, he believed that the SB had already been incorporated.

The passenger, who also owned a conventional (tailwheel) landing gear RV-6, stated that whether the SB had been incorporated or not would have made no difference in the outcome of the accident. The airplane landed very fast; he didn't know how fast, and it hit the ground so hard that it bounced back up in the air. When it did, the pilot stalled it. The airplane came back down on the nose wheel, which then dug into the ground, and the airplane nosed over.