FORT LAUDERDALE, FL, USA
N4376N
PUSHKAR HORNET
While in cruise flight and trailing behind another aircraft, the pilot reported a loss of engine power to the preceding pilot. Subsequently, the accident pilot reported there was no cylinder head temperature and the airplane had become a 'glider.' The preceding pilot reversed course and observed the accident airplane bank to the left, then descend nose first into the ground. Ground witnesses also observed the airplane turn left, then pitch nose down and descend into the ground. During the post crash examination of the engine, one rear cylinder spark plug was absent from the cylinder. The spark plug was recovered and an examination revealed that stripped cylinder thread material from the associated spark plug receptacle was lodged in the spark plug thread grooves. Maintenance records indicated that the pilot/owner/builder had replaced four spark plugs 1.5 hours prior to the accident flight.
HISTORY OF FLIGHT On March 20, 1999, about 1000 eastern standard time, an experimental Pushkar Hornet, N4376N, owned by a private individual, lost power during climb and impacted with the ground near unincorporated Fort Lauderdale, Florida. Visual meteorological conditions prevailed at the time, and no flight plan was filed for the 14 CFR Part 91 personal flight. The airplane was destroyed. The private-rated pilot was fatally injured. There were no injuries to any persons on the ground. The flight had originated from North Perry Airport, Hollywood, Florida, before 0900, and had stopped at a private airstrip (MacIvor Airstrip), for about 1 hour, en route to Pahokee, Florida. The flight took off from the private airstrip about 10 minutes before the accident. After departure the pilot of N4376N made radio contact, on a prearranged frequency, with the pilot of another aircraft that had taken off before him, and both aircraft were to fly in trail of each other to the destination airport. According to the pilot of the other airplane, both airplanes were heading northwest when radio contact was made. The pilot of N4376N said, "...I'm not getting full power or good power." According to the other pilot, "...I said, as I turned to locate him, do you want to make a precautionary at MacIvor's [the private airstrip]. He said 'Roger.' When I saw him he was already heading southeast towards MacIvor's Field, and approximately 1 mile southeast of me." The next radio transmission the pilot of N4376N said, "...no temperature on the back cylinder...I am a glider...as I watched he made what looked like a left turn towards the west-the plane abruptly nosed straight down with a half turn, and hit the ground nose down." Other witnesses also saw the airplane heading in a southeasterly direction, then turn to the left, and descend nose first into the ground. Some ground witnesses heard the engine "sputter" before it descended. The accident occurred during the hours of daylight approximately 26 degrees, 02 minutes north, and 080 degrees, 22 minutes west. PERSONNEL INFORMATION Information on the pilot is contained in this report on page 3, under First Pilot Information. The pilot had received his private pilots certificate on March 3, 1999, and had 1.5 hours of total flight time in this kind, make and model airplane. AIRCRAFT INFORMATION Information obtained from the owner/builder's assembly log revealed that he had purchased the kit for the airplane April 23, 1998, and on June 9, 1998, he started to assemble the airplane. On July 9, 1998, he received the engine, and wrote in the log, "...4 [four] broken spark plugs, no engine manual. Received new gap covers...ordered manual and 12 new spark plugs." August 7, 1998, "Received 12 new spark plugs and Hirth engine manual. August 11, 1998, "...Installed sensors for EGT's [exhaust gas temperature], CHT's [cylinder head temperature], put in 4 new spark plugs." August 13, 1998, "...Installed and wired left and right CHT/EGT temperature sensor [NOTE: The CHT sensor was located in the rear cylinder, with the spark plug that was found out of the hole.]. Torqued spark plugs. Installed front gap cover." The airplane and engine were put into service on December 1, 1998, and had accumulated 1.5 hours of total flight time since new. METEOROLOGICAL INFORMATION Meteorological information is contained in this report on page 3, under Weather Information. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot, on March 21, 1999, at the Broward County Medical Examiner's Office, Fort Lauderdale, Florida, by Dr. Linda Rush. According to the Medical Examiner's report the cause of death was "...Multiple Blunt Trauma." Toxicological tests were conducted at the Federal Aviation Administration, Research Laboratory, Oklahoma City, Oklahoma, and revealed, "No ethanol or drugs detected in Blood." WRECKAGE AND IMPACT INFORMATION The airplane impacted into the back yard of a private residence. The airplane was found nose down. Both wings were still attached and the leading edges of both wings were lying parallel to the ground. The entire leading edge of each wing was crushed rearward. The empennage and tail section were in one piece, but had broken downward just aft of the cabin and was found on the ground lying on the right horizontal stabilizer. The entire tail section did not display any visual damage. Control continuity was established to all the flight controls through the cables. The cockpit area was crushed rearward and destroyed. Examination of the engine at the crash site revealed that a spark plug on the rear cylinder was found completely out of the cylinder hole. There were a total of four spark plugs and the other three were found tight in the cylinder. The engine was removed from the airframe. The rear cylinder and both spark plugs were removed from the engine, for a more detailed examination. TEST AND RESEARCH The rear cylinder, two sparks, and the spark plug harness were taken to the NTSB Materials Laboratory, Washington, DC, for examination. The spark plug that was found out of the cylinder at the crash site was labeled as No. 1, and the other plug from the cylinder was labeled No. 2. Visual examination of spark plug No. 1 revealed that the three outermost threads contained light color metal deposits, determined to contain "aluminum" as a major peak. The undamaged threads in plug No. 1 contained "nickel as a major peak with minor peaks of iron, copper, and molybdenum." The threads of spark plug No. 2, the spark plug that remained in cylinder, revealed no evidence of foreign metal deposits in the threads. Examination of the cylinder revealed that three threads located at the mouth of the hole for spark plug No. 1 were "stripped." No evidence of thread damage was found in the hole in cylinder No. 2. Further examination of the holes revealed that both contained washer imprints on the spark plug seat faces. The results of the metallurgical examination revealed that the cylinder material on the three outermost threads on spark plug No. 1 corresponded to the three stripped threads in the cylinder hole. The thread damage was an indication that spark plug No.1 was cross-threaded, partially inserted, or improperly torqued when installed. The threads of spark plug No. 2 were found to be fully engaged with the threads of the corresponding hole. (See the NTSB Materials Laboratory Factual Report attached to this report.) ADDITIONAL INFORMATION The airplane was released to Mr. Steve Smalley, representing the owner's insurance company, on March 20, 1999. The cylinder, spark plugs, and harness were shipped by Registered Mail (R 671 308 467) to Mrs. Joseph Pushkar, wife of the owner, directly from the NTSB Materials Laboratory, on May 28, 1999.
the pilot's (owner/builder) inadvertent aerodynamic stall of the airplane after a total loss of engine power. Factors were the pilot's improper maintenance action and his lack of total experience in the airplane type.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
