Summary
On June 18, 2013, about 1125 eastern daylight time, an Israel Aircraft Industries (IAI) 1124 airplane, N112EM, was substantially damaged following a landing gear collapse at Cincinnati Municipal Airport (KLUK). The flight instructor, pilot, and pilot-rated passenger did not report any injuries. The airplane was registered to and operated by E. Micah Aviation Incorporated under 14 CFR Part 91 as an instructional flight. Day visual meteorological conditions prevailed, and no flight plan was filed. The local flight departed KLUK about 1045.
Sequence of Events
According to the cockpit voice recorder (CVR), the pilot and flight instructor briefed an ILS approach to runway 21L at KLUK. The flight instructor requested two ILS approaches from air traffic control and was given missed approach instructions. After contacting the KLUK control tower, the instructor requested and received clearance for the "option," permitting various landing maneuvers.
During the approach, the instructor verbally coached the student. The student had over 3,600 total flight hours but was attempting his first landing in this airplane type and had not landed a high-performance or turbine-powered airplane in several years.
As the pilot flared for landing, the CVR recorded a steady tone with the frequency of the trim movement buzzer, which continued for 8.5 seconds. Immediately after touchdown, the instructor said, "no, no, no, we're not stopping." A half-second rumbling sound was recorded, and the trim buzzer stopped. One second later, the student said, "okay, my bad." At 1125:01.5, the gear warning horn tone began and continued until the end of the recording. At 1125:03, a 'thunk' was heard, followed by scraping. At 1125:07, scraping resumed for about 20 seconds, decreasing as the airplane decelerated.
The airplane came to a stop near the end of runway 21L with the left landing gear collapsed outward. The left gear had retracted outward per design. Airport personnel hoisted the airplane for recovery; while being raised, the left gear dropped by gravity to a down-and-locked position. No damage was observed to the left landing gear or its brace assemblies. Scrape damage consistent with runway contact was found on the underside of the right wing near the wingtip. Substantial damage occurred to structural areas of the fuselage.
Witness Statements
The flight instructor stated that the airplane never lifted off during the touch-and-go and suspected a mechanical failure of the landing gear. The pilot was unsure of the sequence and felt the instructor was rushing the touch-and-go, as he perceived ample runway existed to accelerate further before rotation. Neither recalled moving the landing gear handle.
The pilot-rated passenger, seated aft, said the landing was normal. When he heard the instructor's command to continue, he leaned back and lost view of the cockpit. He observed the airplane become airborne for one to two seconds, bank right, and contact the runway with the right wingtip. The airplane then yawed left, and the left landing gear collapsed upon runway contact. He did not notice if the gear handle was moved.
A maintenance worker at the departure end of the runway saw a normal landing, then a bank to the right and right wingtip strike, followed by a yaw left and left gear collapse.
Post-Accident Examination
FAA personnel examined and tested the landing gear. The gear hydraulically retracts outward into strut and wheel wells under the wing. It locks in the up position via a lock assembly in each wheel well; in the down position, it is locked and braced by side and jury brace assemblies.
The airplane was placed on jacks, and the gear was cycled several times with no anomalies. No damage was observed to the gear or brace assemblies. A second test examined adjustment criteria from the IAI 1124 maintenance manual; the gear cycled normally. Clearance between the piston plunger end of the unlock cylinder and the unlock tang on the back of the upper jury brace was correct, ensuring proper piston travel.
A review of manufacturer records and NTSB accident data revealed no similar IAI 1124 landing gear incidents or accidents. The manufacturer stated that jury and/or side brace damage would be evident if the gear was down and locked during a collapse sequence.