Thursday, October 23, 2014

Zenith Zodiac XL, N601WR: Accident occurred October 21, 2014 in Mountain Home, Arkansas

NTSB Identification: CEN15LA023
14 CFR Part 91: General Aviation
Accident occurred Tuesday, October 21, 2014 in Mountain Home, AR
Probable Cause Approval Date: 06/09/2015
Aircraft: TUBERVILLE ZODIAC XL, registration: N601WR
Injuries: 1 Serious, 1 Minor.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot reported that he had recently built the airplane. The pilot operated the engine for about 4 hours, and the engine operated normally during the ground tests. During takeoff on the airplane’s first flight, he advanced the throttle slowly to 2,550 rpm, and the airplane lifted off the runway about 60 mph. About three-quarters down the runway and about 50 ft above ground level, the engine began to lose power. The pilot attempted to return to the runway by turning left. The pilot completed a 180-degree left turn, but the engine rpm had reduced to about 1,925 rpm, and the airplane was unable to maintain altitude. Data from the airplane’s engine monitoring device (EMD) indicated that the airplane reached a maximum airspeed of about 65 mph; the last airspeed reading before ground impact was 41 mph. The pilot attempted to land in a small clearing, but the airplane clipped a tree before landing. The airplane sustained substantial damage to the wings and fuselage during the ground impact. 

Data from the EMD also indicated that the engine operated for about 12 minutes from engine start to ground impact. The data indicated that the engine oil pressure, engine oil temperature, and fuel pressure were normal throughout the flight but that the Nos. 2, 3, and 5 cylinder head temperatures exceeded 500 degrees F. A postaccident examination of the engine and carburetor revealed no evidence of mechanical malfunctions, heat distress, or failures that would have precluded the engine’s operation. The reason for the increased cylinder head temperature indications and the partial power loss could not be determined. 

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The partial loss of engine power during takeoff for reasons that could not be determined because postaccident engine examinations revealed no anomalies that would have precluded normal operation.

On October 21, 2014, about 1745 central daylight time, an experimental amateur-built Tuberville Zodiac XL airplane, N601WR, sustained substantial damage when it struck a tree and impacted the ground during a forced landing due to a partial loss of engine power after takeoff from the Baxter County Airport (BPK), Mountain Home, Arkansas. The pilot received minor injuries and the pilot-certificated passenger received serious injuries. The airplane was registered to and operated by a private individual under the provisions of the 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The airplane was departing BPK on a local flight at the time of the accident.

The pilot reported that he purchased the airplane from a previous owner in 2011 when it was still in the build stage. The pilot completed building the airplane in 2014. The airplane was in the Phase I flight testing process, which required at least 40 hours of operation in the assigned geographic area. The accident flight was the first flight of the airplane. 

The pilot asked the pilot-certificated passenger to fly with him on the first flight because the pilot-certificated passenger was an experienced agricultural pilot with numerous flight hours in other experimental amateur-built airplanes. The pilot-rated passenger reported that he went on the first flight to assist the pilot, but not to fly the airplane. 

The pilot reported that he had operated the engine for about 4 hours prior to the first flight. The ground tests of the engine included static run-ups, taxi and high-speed taxi tests, and "crow hops." The pilot explained that crow hops were high-speed taxi tests where the pilot would get the airplane airborne to about 15 to 20 feet in the air, and then reduce the throttle and land on the airplane on the runway. He reported that the engine operated normally during the ground tests.

The pilot reported that during the ground run-up prior to the first flight, he advanced the throttle to 2,550 rpm and the engine operated normally. During takeoff from runway 5 (5,001feet by 75 feet, asphalt) at BPK, he advanced the throttle slowly to 2,550 rpm and the airplane lifted off the runway about 60 mph. About 3/4 down the runway and about 50 feet above ground level (agl), the engine began to lose power. The pilot attempted to return to the runway by turning left. About 90 degrees through the turn, the pilot heard the cylinder head temperature (CHT) audible warning. The pilot had completed a 180 degree left turn, but the engine rpm was about 1,925 rpm and the airplane was unable to maintain altitude. The pilot attempted to land in a small clearing, but clipped a tree prior to landing. The airplane sustained substantial damage to the wings and fuselage during the ground impact. 

The airplane was equipped with an engine monitoring device which the pilot downloaded. The data indicated that the engine was operated about 12 minutes from engine start to ground impact. The data indicated that the engine was delivering 2,583 rpm during takeoff and climbed to about 64 feet agl. About one minute after takeoff, the engine rpm began to decline to 1,924 rpm. The airplane impacted the ground about 2 minutes after takeoff. The data indicated that the No. 2, No. 3, and No. 5 CHTs reached 628 degrees F, 586 degrees F, and 524 degrees F, respectively, while still airborne. The pilot reported that the CHT audible warning was set to sound when 500 degrees F was reached. The data indicated that the engine oil pressure, engine oil temperature, and fuel pressure were normal throughout the flight. The data indicated that the maximum airspeed reached was about 65 mph. The last airspeed reading before ground impact was 41 mph.

The engine was examined at an engine overhaul facility under National Transportation Safety Board oversight. The visual examination of the engine revealed that the distributor cap was broken. The oil filter was crushed. The upper right baffling was damaged. The cylinder head temperature wires were cut. The carburetor was not sent with the engine, and the air intake tubes to the carburetor were not sent. The valve cover over the No. 6 cylinder had slight crush damage. 

The engine timing was checked using an ohm meter. The points opened about 10 degrees before top dead center. The firing order of the cylinders was 1, 4, 5, 2, 3, and 6. The cold cylinder compression test obtained the following results: No. 1 - 70/80; No 2 - 50/80; No. 3 - 40/80; No. 4 - 50/80; No. 5 - 15/80; and No. 6 - 64/80. The spark plugs were examined. The No. 3 spark plug ground strap had bluing. The other plugs exhibited a rich, but normal appearance. The No. 3 cylinder had some oil in it during the compression test. 

The No. 6 rocker arm was slightly loose. Otherwise, the rocker arms and push rods were normal with no anomalies. The Nos. 1, 3, and 5 cylinder head was removed. The Nos. 1 and 3 cylinders exhibited some exhaust blow-by. The breakout torques had felt low to the technician as he removed the lower bolts. The Nos. 2, 4, and 6 cylinder head was removed with a torque wrench to measure the break-out torque values. The minimum torque value was listed as 27 foot pounds. The bottom head bolts had breakout torques below 27 ft/lbs. The top head bolts had a breakout force of about 30 ft/lbs. There was no blow-by observed on the Nos. 2, 4, and 6 cylinder head. 

The No.5 piston exhibited score marks on the side of the piston above the top compression ring. The top compression ring was stuck next to the two score marks. There were score marks inside the cylinder wall associated with the two score marks above the top compression ring. The top of the No. 5 piston was normal. The second compression ring was normal. The piston rings on the other pistons moved freely and normal. There was light scoring noted on Nos. 2, 3, and 4 cylinders. 

The crankshaft, camshaft, connecting rods, and bearings were normal and no discoloration was present. Drivetrain continuity was confirmed with the distributor moving. There was no evidence of extreme temperatures in any of the cylinders, and no evidence of detonation or pre-ignition. The cylinder head temperature (CHT) probes were normal. 

There was normal carbon buildup on all the pistons except No. 4. The No. 4 piston, cylinder head, exhaust and intake valves did not exhibit carbon buildup. The No. 4 exhaust valve was not seating completely. There was leakage toward the top of the valve seat. The No. 4 exhaust valve exhibited some erosion of the aluminum cylinder head casting next to the exhaust valve seat area. The No. 2 cylinder exhibited some exhaust valve leaking. The No. 5 cylinder head exhaust valve seat was sunken slightly deeper in the head than the Nos. 1 and 3 exhaust valve seats. The No. 5 exhaust valve was not seating. The Nos. 2, 4, and 5 exhaust valves exhibited some leaking. All intake valves were seating. 

The carburetor was examined at a component overhaul facility under NTSB oversight. The examination revealed that the throttle shaft was stiff due to the throttle arm being bent. The stop was broken due to impact damage. The float bowl was clean and the metal floats and the float level were normal. It had a one-piece verturi and the venturi main discharge was clean. The accelerator pump was normal. 


NTSB Identification: CEN15LA023 
14 CFR Part 91: General Aviation
Accident occurred Tuesday, October 21, 2014 in Mountain Home, AR
Aircraft: TUBERVILLE ZODIAC XL, registration: N601WR
Injuries: 1 Serious,1 Minor.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On October 21, 2014, about 1745 central daylight time, an experimental amateur-built Tuberville Zodiac XL airplane, N601WR, sustained substantial damage when it hit a tree and impacted the ground during a forced landing due to a partial loss of engine power after takeoff from the Baxter County Airport (BPK), Mountain Home, Arkansas. The pilot received minor injuries and the passenger received serious injuries. The airplane was registered to and operated by a private individual under the provisions of the 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The airplane was departing BPK on a local flight at the time of the accident.

The pilot reported that he departed from runway 05 at BPK and climbed to about 75 feet. The engine started to lose power, and the pilot made a shallow turn to return to the airport. The airplane lost altitude gradually and it hit an oak tree while on downwind. The airplane impacted the ground in a small clearing.

The airplane was equipped with a rebuilt Corvair engine. The pilot indicated that two of the cylinders appeared to be running hot and approaching 500 degrees Fahrenheit during the accident flight.


FAA Flight Standards District Office: FAA Little Rock FSDO-11

ANDREW D TUBERVILLE ZODIAC XL N601WR http://registry.faa.gov/N601WR

 
Andrew Tuberville, of Lakeview, owner of the Zenith Zodiac XL.
(Photo: Zenith Builders and Flyers website) 


 
A picture of Andrew Tuberville's  Zodiac XL that was involved in the crash near Ozark Regional Airport on Tuesday.
(Photo: Zenith Aircraft Builders and Flyers)



MIDWAY — Two men injured in a northern Arkansas single-engine plane crash are recovering.

Thirty-six-year-old pilot Andrew Tuberville was released from the Baxter Regional Medical Center on Wednesday. Forty-eight-year-old passenger Ronnie Skaggs is listed in good condition at Mercy Hospital in Springfield, Mo.

The experimental airplane crashed Tuesday evening in a wooded area northwest of Ozark Regional Airport in Baxter County. Both men suffered head injuries but were able to walk away from the wrecked aircraft.

The cause of the crash is unclear. The Federal Aviation Administration is investigating.

- Source: http://swtimes.com



  
(Editor's Note: Ronnie Skaggs, of Cotter, remains a patient Thursday morning at Mercy in Springfield, Mo., recovering from injuries he suffered as a passenger in the experimental plane crash off Baxter County Road 913 near the Ozark Regional Airport on Tuesday night. A hospital spokesperson said Skaggs continues to be listed in good condition. Both Skaggs and pilot Andrew Tuberville, of Lakeview, who was treated and released from Baxter Regional Medical Center the night of the crash, suffered head injuries.) 

 MIDWAY – Andrew Tuberville watched silently Wednesday afternoon as Jim Baker, owner of Baker Truck-Equipment Repair and Wrecker Service, used a Kubota forklift to remove the wreckage of his Zodiac XL homebuilt aircraft from a woodline near Ozark Regional Airport.

Less than 24 hours earlier, Tuberville, of Lakeview, was at the controls of the plane when it crashed approximately 25 yards into a wooded area off Baxter County Road 913, injuring him and Ronnie Skaggs, a friend and fellow aviation enthusiast.

Tuberville was released from Baxter Regional Medical Center on Tuesday night, while Skaggs, a Cotter resident, continued to be listed Thursday in good condition at Mercy Hospital in Springfield, Mo., where he was airflighted from a location near the site where the aircraft went down. Both men suffered head injuries in the crash.

In a key piece of information released Thursday from the incident report by Baxter County Sheriff's deputy Jeremy Thrasher, Tuberville told BCSO investigators while at the hospital that the crash occurred approximately 1 minute after takeoff from Ozark Regional Airport. The report continues that Tuberville said the engine stalled and the aircraft went down roughly one-half mile from AR Highway 126 North.

A Federal Aviation Administration investigator arrived Wednesday from the Southwest Region office in Fort Worth, Texas, to begin the investigative process. A cause for the crash is still under investigation, according to FAA spokesman Lynn Lunsford, who said a preliminary report from the National Transportation Safety Board would likely be available within 10 business days.

Tuberville and several friends were at the crash site Wednesday and began the process of salvaging what they could of the single-engine, two-seat plane. After several parts were removed, Baker moved into position with the forklift.

Baker delicately inched the fork under the fuselage until what was left of the propeller was touching the base of the fork, and the tines were past the back of the wing. Baker then lifted the aircraft free, and drove it down CR 913 to the nearby home of one of Tuberville's friends.

Plane not so experimental

The plane Tuberville built and was flying was assembled from a kit manufactured by Zenith Aircraft Corporation. The company, located in Mexico, Mo., was formed in 1992. Zenith has several different models available for aviation enthusiasts wishing to build their own aircraft.

While the FAA categorizes planes such as the Zodiac XL as an experimental aircraft, the name is a bit misleading, according to custom-built plane owners. Within the FAA's experimental aircraft category, there are several subcategories, including amateur-built aircraft, the category Tuberville's plane falls within.

This particular subcategory recognizes planes, such as the Zodiac XL, are often built using well-established designs. In the case of the Zodiac XL, noted light aircraft designer Chris Heintz provided the design. An aeronautical engineer, Heintz first designed an aircraft in 1969.

The Zodiac design has been around for several years, with thousands of the aircraft built at home.

"It's been around for about 20 years," Dick Knapinski, a spokesperson for the Experimental Aircraft Association, said of the Zodiac XL. "It's generally well-regarded. Usually, with aircraft as popular as this, when a problem occurs, it's widely known throughout the aviation world in a short amount of time, and a solution is quickly found and distributed."

Pilots and planes certified

Before an experimental plane can be flown, it must be inspected by the FAA. The builder of the plane must keep logs and take photographs during the building process. Those logs and photos are turned over to the inspector, who makes the decision as to whether a plane receives an airworthiness certificate, Knapinski said.

Once a plane is certified, it then falls under the same inspection regulations as commercially built aircraft. That means, Knapinski said, planes must be inspected once a year or every 100 flight hours.

According to the FAA Registry, Tuberville's Zodiac XL was certified on July 19, 2012 and it's current certification expires on July 31, 2015.

Experimental aircraft safety
The safety record of experimental aircraft is similar to that of commercially built aircraft, according to Knapinski, who said pilot error is the most common reason for experimental aircraft crashes, rather than mechanical failure.

There are two areas where crash incidences increase for pilots of experimental aircraft, according to Knapinski. The first area is during the first few hours a new aircraft is flown.

"That period, what you might call the shakedown period, sees more crashes," Knapinski said. "The other area is when a pilot first transitions to a new aircraft."

By The Numbers
Commercially-built plane crashes in the Twin Lakes Area since 1970

• 40 Nonfatal incidents

• 8 Fatal incidents resulting in 18 deaths

Amateur-built plane crashes in the Twin Lakes Area since 1970

• 3 Nonfatal

• 0 fatal

- Source:   http://www.baxterbulletin.com




No comments:

Post a Comment