Gurdon, AR, USA
N138ZX
M-SQUARED AIRCRAFT SPRINT 1000
The pilot reported that he and a passenger had just departed on a local, personal flight when the engine “suddenly stopped.” Shortly thereafter, the engine seized, and the airplane began to descend rapidly. The pilot deployed the airplane's ballistic parachute about 200 ft above ground level, and the airplane then landed hard in a residential area, which resulted in substantial damage to the wings and fuselage. The pilot recalled that, during the takeoff and climb, the instruments showed no unusual indications and that the engine made no unusual sounds. Examination of the engine revealed that the top of the MAG piston ring had failed, which resulted in damage to the MAG piston and cylinder walls. Both rubber PTO and MAG carburetor intake sockets were worn and cracked. Complete engine records were not available, and no record was found indicating that the engine had been overhauled during its 23 years of operation. The engine manufacturer recommended that the engine should be overhauled every 300 hours or 5 years, whichever occurred first, and that the rubber carburetor intake sockets should be replaced every 5 years or as signatures of deterioration were detected. Cracked rubber carburetor intake sockets can result in a lean mixture and lead to a piston seizure. The inadequate maintenance of the engine likely led to the failure of the MAG piston ring and the subsequent loss of all engine power due to a piston seizure.
On May 21, 2018, about 1915 central daylight time, an M-Squared Sprint 1000 light-sport airplane, N138ZX, was substantially damaged when it was involved in an accident near Gurdon, Arkansas. The pilot and passenger were seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported to the Federal Aviation Administration (FAA) inspector that the airplane had just departed from runway 26 at Gurdon Lowe Field. When the airplane was about 800 ft above ground level (agl), "the engine suddenly stopped." As the pilot looked for a suitable landing site, the "engine seized up", and the airplane began to descend rapidly. The pilot deployed the airplane's ballistic parachute about 200 ft agl. The airplane descended and landing hard in a residential area. The airplane's wings and fuselage were substantially damaged. The pilot recalled that during the takeoff and climb there were no unusual indications from the instruments, nor any unusual sounds from the engine. The engine was examined by the FAA inspector with technical assistance from the engine manufacturer. Examination of the engine revealed that the top of the MAG piston ring had failed resulting in damage to the MAG piston and cylinder walls. The examination also noted vertical scoring on the PTO cylinder, and significant vertical scoring on the MAG cylinder. In addition, both rubber PTO and MAG carburetor intake sockets were worn and cracked. Complete engine records were not available and there was no record that showed that the engine had been overhauled during its 23 years of operation. The manufacturer recommends an engine overhaul be performed every 300 hour or 5 years, whichever occurs first. The rubber carburetor intake sockets should be replaced every 5 years or when signatures of deterioration are detected.
Inadequate engine maintenance, which resulted in the failure of the MAG piston ring and the subsequent total loss of engine power due to a piston seizure.
Source: NTSB Aviation Accident Database
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