NTSB Factual Report

On July 1, 2005, at 1059 Hawaiian standard time, a PA-23-160, N3369P, veered off the runway during a single engine landing, and the landing gear collapsed at the Honolulu International Airport, Honolulu, Hawaii. During the veer from the runway, the left wing impacted a taxiway light. The certified flight instructor (CFI) and private pilot undergoing instruction (PUI) were not injured; the airplane sustained substantial damage. The CFI was operating the privately registered airplane under the provisions of 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan had been filed. The airplane departed from the Honolulu airport about 1015 for the local area instructional flight.

According to the CFI, the left engine could not be restarted following a practice shutdown and feather. Because the hydraulic pump is located on the left engine, the CFI was aware that the landing gear would have to be manually extended. They elected to return to the departure airport and performed the emergency landing gear extension procedures by pumping the handle about 10 to 20 times. They did not receive a down-and-locked landing gear indication of any of the three green lights, nor did the landing gear lever return to the neutral position. While on final approach, the tower controller stated that the gear appeared down-and-locked. The CFI proceeded inbound for landing. On short final, an unidentified aircraft reported on the tower frequency that the nose gear was not down-and-locked. Due to the single engine operation, the CFI did not think that it was feasible to perform a go-around so he landed the airplane on runway 4R. Upon touchdown, the airplane veered to the left and approximately 4 feet of the outboard left wing sheared off when it impacted a taxiway light. During the approach to landing, the pilot elected not to use the Emergency Gear Extender because he did not feel comfortable having the PUI fly the airplane single engine while he applied the Emergency Gear Extender control.

The CFI had performed the emergency gear extension procedure on one other occasion. During that incident, the landing gear lever did not return to the neutral position; however, the three green lights indicating that the gear was down-and-locked illuminated.

In a later written statement, the CFI reported that after securing the left engine, they decided to return to Honolulu. He advised the air traffic approach controller that he had a feathered engine and could not restart it. His PUI flew the airplane while performing an instrument landing system (ILS) 4R approach. At 1,500 feet above ground level (agl) and 6 miles from the airport , the PUI lowered the gear lever and pulled out the hand pump. As the PUI flew the approach, the CFI began pumping the hand pump and completed 10 to 20 strokes before he could no longer move the pump. The CFI saw the nose gear in the mirror (mounted on the engine cowlings); however, none of the green lights illuminated, and the gear lever did not pop back into the neutral position.

The accident flight was the forth occasion in this airplane that the CFI was required to activate the hand pump due to a faulty landing gear system. On the previous occasions, he pumped the handle 30 to 40 strokes until no further pumping was possible. On each of the three incidents, the three gear lights illuminated but the gear lever did not return to the neutral position. On all occasions including the accident flight, the same sensation of stiffness on the hand pump was experienced.

The CFI continued troubleshooting the airplane and they rapidly "pitched and yawed" the airplane, attempting to position the gear down-and-locked. As the CFI was going to ask the tower if the gear appeared down and considering using the Emergency Gear Extender, the air traffic control tower (ATCT) gave the airplane a 360-degree right turn at 500 feet agl. The CFI said that about halfway through the turn "we began flirting with Vmc." The PUI continued to fly the airplane but the CFI also was on the yoke because he recognized this as a critical phase of flight. He did not decline the 360-degree turn given by the ATCT because he was focused on the gear, and as a CFI in the area for over 3 years, he has been under constant pressure to accommodate ATCT instructions.

As they rolled out from the turn, the CFI asked the ATCT to confirm that the landing gear appeared to be down. They replied affirmatively and the CFI took complete control of the airplane. Just prior to the airplane's entry into the flare, someone blind transmitted over the radio that the nose gear did not appear down. The CFI then reactively applied power and the airplane rolled to the left and then impacted the ground.

In the PUI's written statement, she noted that her checkride had been scheduled for the end of March but had been canceled due to a series of mechanical problems involving the landing gear on the airplane. During their return to the airport, the PUI flew the airplane and the CFI provided instruction on conducting a single engine instrument landing system (ILS) approach in visual meteorological conditions. While on the final approach leg following the 360-degree turn, the CFI assumed control of the airplane and the PUI relinquished her control.

According to the Piper Apache owner's handbook, the hydraulic pump is located on the left engine. In the event of a power loss on the left engine, the hydraulic pump is rendered unusable. In order to obtain hydraulic pressure in the event of a hydraulic pump failure or left engine failure, the emergency pump handle should be extended and 30 to 40 pumps are required to raise or lower the landing gear. Upon full extension or retraction, the pump handle will position itself into the neutral position. In the event of a hydraulic system failure caused by a line breakage or a selector valve malfunctioning, the gear can be extended using the Emergency Gear Extender. When this control is pulled, carbon dioxide flows from a cylinder under the floorboards and assists in extending the gear. The Emergency Gear Extender control is located beneath a small cover plate underneath the left pilot's seat.

On July 14, the FAA coordinator and an FAA airworthiness inspector examined the landing gear with an aviation maintenance technician and performed a functional check. The inspectors noted that the landing gear lever was positioned close to the neutral position. Interviews with the CFI and PUI indicated that the PUI placed the lever in the down position but that the CFI did not verify its position. With the airplane on jacks, the emergency landing gear system was actuated through the hand pump and extended into the down-and-locked position with no operational anomalies noted.

NTSB Probable Cause

the flight crew's failure to ensure that the landing gear lever was in the full down position prior to utilizing the hand pump, and the certified flight instructor's failure to utilize the blow down emergency landing gear system. The instructor's inadequate supervision of the flight and failure to maintain Vmc during an attempted go-around was also causal.