N78BZFlight Design Gmbh CTLS · 2008

On May 10, 2011, at 1446 eastern daylight time, a Flight Design CTLS, N78BZ, was substantially damaged during a forced landing near Troy, South Carolina. The certificated flight instructor (CFI) and certificated private pilot were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the flight, which departed Malcolm McKinnon Airport (SSI), Brunswick, Georgia, about 1330, and was destined for Greenville Downtown Airport (GMU), Greenville, South Carolina. The personal flight was operated under the provisions of Title 14 Code of Federal Regulations Part 91.

According to the CFI, the airplane was serviced with a total of 10 gallons of fuel, evenly distributed between the left and right wing fuel tanks, prior to departure from SSI. The CFI confirmed, by use of a fuel quantity measuring stick, that each tank contained 7.5 gallons of 100 low lead aviation fuel, which he estimated was sufficient for approximately 3 hours of flight time.

While in cruise flight at 3,500 feet mean sea level, about one hour after departure from SSI, the pilots received a low fuel pressure warning on the airplane's multifunction display (MFD). The CFI assumed control of the airplane while the private pilot handled radio communications, requesting to divert to Greenwood County Airport, Greenwood, South Carolina (GRD), at which time the engine began to sputter. The CFI maneuvered the airplane towards a road to execute a forced landing, and the engine experienced a total loss of power. During landing, the airplane's right wing impacted a telephone pole guy wire. The right wing separated from the airframe, and the airplane came to rest upright in a ditch. The private pilot's statement was consistent with that of the CFI.

The CFI held a commercial pilot certificate with ratings for airplane single-and multi-engine land, and instrument airplane, as well as a flight instructor certificate with a rating for airplane single-engine. He reported 246 total hours of flight experience, 15 hours of which were in the accident airplane make and model.

The second pilot held a private pilot certificate with a rating for instrument airplane. He reported 319 total hours of flight experience, 37 hours of which were in the accident airplane make and model.

According to FAA records, the light sport airplane was manufactured in 2008 and was powered by a 100-hp Rotax 912ULS reciprocating engine. The airplane's most recent annual inspection was completed on April 2, 2011 at a total time in service of 284 hours. At the time of the accident, the airplane had accumulated a total time of 296 hours.

The 1456 weather observation at Greenwood County Airport (GRD), located approximately 18 miles north of the accident site, included calm winds, clear skies below 10,000 feet, temperature 31 degrees C, dew point 16 degrees C, and an altimeter setting of 29.94 inches of mercury.

A South Carolina State Trooper, who examined the airplane's fuel tanks at the site, reported that the right wing contained a "sheen" of fuel. He did not observe any fuel leaking from the wing or fuel on the ground in the vicinity of the wing. He stated that the left wing tank was "completely dry." He stated that the CFI drained a small amount of fuel from the gascolator, and the fuel was light blue in color and free of contaminants.

A local mechanic also responded to the site to assist in securing the airplane's ballistic recovery system (BRS). After securing the BRS, the mechanic drained approximately one cup of fuel from the gascolator.

A Federal Aviation Administration (FAA) inspector examined the airplane the following day, after it had been recovered to a hangar at GMU. The inspector reported that neither the wings nor engine compartment revealed evidence of fuel leaking. The engine's upper spark plugs were removed and exhibited low wear. The engine was rotated by hand at the propeller and compression was obtained on all cylinders. There was no fuel observed in either of the two carburetors.

A Rotax representative and an FAA inspector examined the engine on June 22, 2011. The carburetors were removed and examined, and found to be clean and dry. The spark plugs were replaced, and a new propeller was installed on the engine. A fuel can was plumbed to the engine, and the engine was primed with fuel. The engine was started and ran from the idle setting up to 3,800 rpm with no anomalies observed. The magnetos operated normally when checked. Engine temperature and oil pressure fell within the normal range throughout the test run.

Fuel System

The airplane was equipped with two wing fuel tanks, with one 17-gallon capacity tank located in each wing. The fuel was fed by gravity from the tanks through a filter, into the gascolator, and from the gascolator to the engine and the two carburetors. Of the 34 gallons total fuel capacity, 32 gallons were usable.

The airplane was also equipped with a Dynon D120 engine monitoring system (EMS), which provided information on current fuel consumption, total consumption since takeoff, and remaining fuel quantity. The remaining fuel quantity indication required that the pilot program the EMS with the correct amount of fuel in the tanks prior to takeoff. Fuel quantity could also be observed using clear tubes located at each wing root inside the cockpit.

According to a Flight Design Aircraft Operation Instructions Performance Supplement, the engine's fuel consumption in cruise flight at 3,500 feet with a power setting of 5025 rpm (75% maximum cruise power) was 4.8 gallons per hour (gph).

Non-Volatile Memory

The Dynon D120 EMS was removed from the airplane and retained for examination at the NTSB Vehicle Recorders Laboratory. The unit was configured to record data at 1-second intervals, a fidelity which provided 41 minutes of recorded data. Data retrieved from the device recorded the last 41 minutes of the accident flight, from 1405 to 1446 EDT.

Fuel pressure data from 1405 until approximately 1438 recorded an average value of 3.9 psi. At 1438:54, fuel pressure dropped to 3.5 psi and continued to drop for the remainder of the flight, with an average value of 1.3 psi.

Engine fuel flow data from 1405 until 1438:37 recorded an average fuel consumption of 5.3 gph. During the next three seconds, the recorded gph value dropped from 4.9 to 3.6 before further dropping to 0 gph. Recorded fuel flow values continued to rise and fall for the next 6 minutes, mostly within a range of 8-13 gph, but indicating as high as 95 gph, with an average consumption of 21.5 gph. At 1444:13, fuel flow dropped to 0 gph.

The average engine rpm during cruise flight from 1405 until approximately 1441 was 5007 rpm. During the time between 1441 and the total loss of engine power at 1844:08, the rpm fluctuated, with an average of 2795 rpm.

At the start of the recording, EMS data indicated 9.5 gallons of fuel remaining. The lowest fuel remaining value, recorded at the end of the flight, was 4.6 gallons.

Flight track data obtained from the EMS revealed that the airplane was on a constant northwest heading from 1405 until approximately 1442, when the airplane began a left turn towards the forced landing site. The unit did not record altitude information.