Unsecured Cockpit Door Focus of NTSB Probe Into Fatal RV-10 Crash

The January 2 accident was caught on a video surveillance camera across the street from the airport. Audio shared by Los Angeles’ KABC-TV indicated the kitbuilt aircraft took off from KFUL around 2 p.m. PST from Runway 24 with the pilot and his 16-year-old daughter on board.

According to a preliminary accident report released by the National Transportation Safety Board (NTSB), a witness who was an acquaintance of the pilot told investigators that he observed the pilot in the left seat of the aircraft and his daughter in the right seat as they taxied from their hangar at the southeast corner of the airport toward the run-up area of Runway 24.

“Security video footage revealed that the airplane was in the run-up area for about three minutes, and during that time although the left door was in the down position, it was not flush with the fuselage,” NTSB said.

The RV-10 is equipped with two gull-wing doors—one on either side of the cabin. The doors are composed mostly of fiberglass and attached to the aircraft by two steel hinges with extension limited by a gas strut. The door is secured by fore and aft aluminium latch pins that extend into UHMW polyethylene pin blocks mounted to the forward and aft pillar structure in the airframe door opening. The latch pins are connected to the door lock handle using a rotary gear assembly. To lock the door, the handle is rotated forward. This extends the latch pins into the pin blocks. The handle contains a release lever that locks the pins in place when they have reached the fully extended position.

To open the door, the release lever must be pressed. The door includes a secondary safety latch system, which was intended to clasp the door in the down position should the lock handle not be manually engaged.

Any uncommanded door opening in flight can be surprising, and if the aircraft has gull-wing doors, there is usually a noticeable change in directional control as the door comes up. Van’s Aircraft addressed this issue in 2010, adding as standard in all RV-10 finish kits a secondary door latch and issuing a service bulletin that recommended the installation of the secondary latch before further flights.

Audio recordings provided by the FAA confirm that at 2:02 p.m., the pilot called the tower for a takeoff clearance.

According to the aircraft’s Electronic Flight Instrument System (EFIS), the pilot instigated the takeoff roll at 2:07 p.m., reaching an altitude of approximately 60 feet above ground level and a ground speed of about 108 knots as it cleared the airport boundary. 

The airplane continued to climb and accelerate on runway heading for about 30 seconds, then the pilot transmitted “immediate landing required” over the control tower frequency.

The tower controller asked the pilot if he could make a left turn and cleared the airplane for landing on any runway. After a few exchanges, the pilot reported that he would return for landing on Runway 24.

According to NTSB, within 30 seconds of the pilot’s request to return, the airplane had completed a 180-degree turn and reached an altitude of 950 feet msl, decelerating to 95 knots. The aircraft entered a left downwind, and about 40 seconds later continued to descend as it passed the Runway 24 threshold, slowing to 85 knots and entering a left turn.

The tower reported there was an unintelligible transmission as the aircraft was at an altitude of 435 feet msl and continued in a steep left turn until it collided with the roof of the factory located 1,500 feet from the approach end of Runway 24.

A witness on the airport ramp south of Runway 24 told investigators he saw the airplane’s takeoff. As it cleared the end of the runway, he noticed the left door was open and up, and he saw an arm reach up and pull the door down.

The NTSB report said that multiple pilot witnesses observed the airplane in the pattern, describing it as “flying lower than normal and banking aggressively left as it made the transition from downwind to base.”

Three witnesses described the left turn to final as aggressive and were concerned that the aircraft would stall. The aircraft then rolled to the right and the nose dropped as a piece of the airplane described as “panel-like” floated to the ground. The airplane—still in a steep bank—descended into the building and exploded.

The NTSB learned during the investigation that the pilot of the aircraft received the primary components for the kit in 2007 and 2008, and completed the airframe in 2011. He received the secondary door latch in January 2010, but examination of the wreckage showed the pilot did not install it.

In addition, investigators determined that the pilot had made a series of modifications to the standard door-locking system, “including the use of solid steel locking pins rather than the kit-supplied aluminum pins, along with replacement of the UHMW polythene door blocks with chamfered aluminum blocks.” The door latch indicator system had also been modified.

NTSB said that the main components of the aircraft—including fuselage, forward cabin, and both wings—were found at the crash site inside the building. The left door was “found on the building’s roof about 150 feet southeast of the impact point and directly below the airplane’s flight path,” the report said. 

According to the NTSB, the door had pulled away from its roof hinges, and the door handle was found just short of the forward closed and locked position. Because it was not fully forward, its locking button had not engaged.

Investigators said that the lock pins were found extended about a half an inch out of the door ends. When the door handle was tested by moving it forward, the pins extended farther and the locking button engaged.

Additionally, NTSB determined that the door latch indicator system supplied with the kit, which consists of four magnetic reed switches mounted individually within each door pillar, was not installed. The switches were configured to confirm via LED warning lamps on the instrument panel that each door pin was in the fully extended and locked position.

“On the accident airplane, it appeared that only two reed switches had been installed, with each mounted to the aft pillars of both doors,” NTSB said. “As such, the modified system would not have warned the pilot if the forward latch pins had failed to fully engage.”