NTSB Factual Report

**This report was modified on February 4, 2015. Please see the public docket for this accident to view a record of the changes.**

HISTORY OF FLIGHT

On May 18, 2012, about 1215 Pacific daylight time, an experimental exhibition Aero Vodochody L-39, N39WT, impacted desert terrain about a 1/2 mile northwest of the Boulder City Municipal Airport (BVU), Boulder City, Nevada. Mach 1 Aviation and Incredible Adventures operated the flight under the provisions of 14 Code of Federal Regulations Part 91. The airline transport pilot and one passenger were fatally injured; the airplane sustained substantial damage to the fuselage and wing assembly. Visual meteorological conditions prevailed for the adventure flight, and no flight plan had been filed for the local flight.

The accident airplane, along with another L-39 (N139CK), departed Van Nuys Airport (VNY), Van Nuys, California, about 0730 on the morning of the accident.

The purpose of the day's flights was to celebrate a birthday for one of the eight passengers, which included a Hollywood Top Gun Adventure flight, in two L-39 Albatross jet airplanes. Each flight was scheduled to be 45 minutes in length, and each passenger would be provided with a film of their flight. Two flights were scheduled for the morning, with the last two flights to take place in the afternoon following lunch. The mornings' flights were uneventful.

The pilot in the lead airplane for the accident flight stated that the takeoff and climb out were normal until he heard the other pilot radio "canopy." He could not elaborate further as to why the accident pilot made that statement.

The passenger in the lead airplane for the accident flight stated that he and the other passenger got into their respective airplanes, but that he did not watch the other passenger get ready for their flight. He stated that he figured out how to put his own seatbelt/safety harness on, and was then instructed about the canopy usage. After the canopies were closed, he was able to hear the pilot of his airplane and the pilot of the other airplane over the radio. The passenger stated that his pilot received a clearance for takeoff and the pilots taxied the airplanes to the runway and came to a stop. The lead airplane was on the left side of the runway and the accident airplane was on the right side of the runway. There was a discussion about the crosswind and if there were any issues on takeoff. The lead airplane would make a left turn, and the number two accident airplane would make a "harder left [turn]." The passenger reported that the takeoff appeared normal. He recalled that they were about 400 feet above the ground, when his pilot instructed the other pilot to stay in formation. The passenger stated that his airplane was in a climbing left turn and he overheard who he thought was the accident pilot over the radio making a mayday call, followed by a canopy call. He looked out of his window and saw the accident airplane in a right turn, then saw it level off followed by a puff of dirt, which he believed was the airplane impacting the terrain. He also recalled seeing the accident airplane fly below one set of power lines. The passenger stated that there were no further communications from the pilot of the accident airplane.

Prior to the two airplanes departing from BVU, a pilot from a flight of 6 military helicopters reported that they were inbound for landing at the airport. After the mayday call was issued by the pilot in the lead airplane, one of the crews of the inbound helicopters reported that they would locate the accident site and land, and render assistance to the pilot and passenger until rescue personnel arrived on-scene. The military pilot reported that he observed the accident airplane on its belly and the engine was still running at full thrust. The pilot in the circling jet was giving instructions on how to get the canopy off and to shut down the engine. The military crew was able to take off the front canopy; however, they were unable to shut the engine down. The engine stopped after about 20 minutes.

Responding rescue personnel reported that upon their arrival they noted two military personnel and an individual from the airport, as well as, two people slumped over inside the airplane. They observed the three individuals attempting to shut down the engine, which they were not able to do. Eventually the engine began to misfire and discharged flames from the rear of the airplane prior to the engine shutting itself down. The front canopy was open rendering the front seat pilot accessible to rescue crews. The rear canopy appeared to be latched on the left side, with the right side of the canopy slightly raised from the fuselage. The canopy had to be forced up and to the left by first responder/emergency personnel in order to gain access to the rear seat passenger.

According to the individual responding from the airport, he noted that when he attempted to idle the engine to shut it down, the throttle appeared to be broken as it had no tension to the control, but the engine sounded as if it was still running at 100 percent power.

According to Boulder City Police Department, they dispatched an officer at 1218. The officer arrived at 1245. The detective reported that the engine was still running upon his arrival at the accident site, and shortly thereafter started to sputter.

Witness Statement

Four of the eight birthday party members were interviewed by the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) and Federal Aviation Administration (FAA) inspectors; they stated that they were driven by bus from their hotel to the Boulder City Municipal Airport. Once they arrived at BVU, they made their way to a Fixed Based Operator (FBO) and were told by FBO personnel that the two airplanes were en route from Van Nuys. While they waited for the airplanes to arrive, the group discussed the order in which they would fly since only one passenger could fly in each airplane at a time. After the airplanes arrived, the group reported seeing two people exit each airplane; pilots and film technicians. The group talked to the pilots and took pictures of themselves with the airplanes. They met inside the FBO in a conference room where they received a briefing of what to expect. Members of the group indicated that there would be four flights; two flights would occur before lunch, the airplanes would be refueled, and then they would have the final two flights.

The passengers did not report any mechanical problems or anomalies during the first two flights. The accident flight occurred on the third flight of the day after the lunch break.

PERSONNEL INFORMATION

The pilot, age 65, held an airline transport pilot certificate (ATP) that was issued February 28, 2011. He also held a flight instructor certificate with ratings for airplane single engine and multiengine, and instrument airplane that was issued on June 8, 2011. The pilot held a second-class medical certificate issued on December 01, 2011. It held the restriction that the pilot must wear corrective lenses. The pilot's logbook was not available for review. On the pilot's most recent FAA medical application dated December 01, 2011, he reported a total time of 5,900 hours with 80 hours accrued in the past 6 months.

According to FAA records, the pilot's ATP certificate was subject to an emergency revocation in September 2009, and the ruling was upheld on November 25, 2009. The revocation was for a period of 1 year, and the pilot was eligible to reapply for his pilot certificate after September 28, 2010. The certificate was reissued on February 28, 2011. He received his initial airline transport pilot certificate on August 31, 1973.

The pilot in the lead airplane, as well as the birthday party group that were flying that day, reported that the pilot appeared to be in good health and was in good spirits.

AIRCRAFT INFORMATION

The two-seat (tandem) low-wing, retractable-gear airplane was an experimental Aero Vodochody L-39 Albatross, serial number 132127. It was a high-performance jet trainer manufactured by Czechoslovakia in 1981. It was powered by an all metal turbofan Ivchenko AI-25-TL engine.

The fuel log and final fuel receipt were obtained from BFE Aviation at Boulder City Airport. The fuel log revealed that the accident airplane had received Jet A fuel two times the day of the accident; once at 0900 for a total of 92 gallons, and again at 1120 for a total of 180 gallons.

Airplane Maintenance

A review of the airplane's logbooks revealed that a 50-hour/6-month inspection had been signed off on January 12, 2012, at an airframe total time of 2,459.8 hours. The last entry in the airplane's logbook was dated January 17, 2012, at an airframe total time of 2,459.8 hours, where the airplane had been signed off for a 100-hour condition inspection. Maintenance records showed that a 50-hour engine inspection was completed on January 12, 2012, at a recorded engine time of 570.3 hours.

The airplane was purchased on December 10, 2009, at an engine total time of 550 hours and an airframe time of 2,440 hours. According to paperwork found in the airplane, the accident pilot had been given authorization to operate the airplane by the airplane's owner.

COMMUNICATIONS

Boulder City Municipal Airport was a non-towered airport; however, it did have an active UNICOM radio frequency, which pilots could announce their intent. The UNICOM radio communications were recorded and a review of the recordings indicated the lead pilot in airplane N139CK, announced over UNICOM that N139CK was a flight of two Albatross fighters and they would be taking the active runway 27L, with a southbound departure followed by a left turn to proceed southeast. The lead pilot then radioed that "139CK flight of two Albatross fighters taking the active 27L making a left turn out." About 2 minutes later on the audio track, the lead pilot radioed "dash two come around," then "dash two you ok?" The accident pilot radioed "canopy canopy," and the lead pilot replied "roger, what are you heading back?" The next radio call overheard on UNICOM was "Mayday Mayday Mayday, we got an airplane down, Mayday Mayday." The entire UNICOM audio track is located in the public docket for this case.

WRECKAGE AND IMPACT INFORMATION

The accident site was approximately 1/2 mile northwest of the airport in flat desert terrain. The airplane came to rest intact between two sets of power lines next to an access road. The first identified point of impact (FIPC) was a flat area adjacent to a berm alongside the road; an impression of the airplane fuselage and wings were observed in the dirt at the FIPC. The debris field from the FIPC to the main wreckage was about 480 feet long. Undercarriage and a gear door were found about 100 feet from the main wreckage. A 25-pound ballast weight was found on the other side of the access road, a 4-foot-deep by 20-feet-wide crater was noted just behind the engine.

MEDICAL AND PATHOLOGICAL

The medical records for the pilot and passenger were reviewed by the NTSB's Chief medical officer. The medical officer reported no evidence of a medical event having occurred by either occupant at the time of the accident.

Pilot

The pilot was recovered from the front seat of the airplane. He was secured by his safety harness.

The Clark County Coroner completed an autopsy on May 18, 2012. The cause of death was listed as multiple blunt force trauma due to an aircraft collision with ground.

The FAA Bioaeronautical Sciences Research Laboratory Civil Aeromedical Institute (CAMI), Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot. Analysis of the specimens contained no findings for carbon monoxide, cyanide, volatiles, and tested drugs.

Passenger

The passenger was recovered from the rear seat of the airplane. He was secured by his safety harness.

The Clark County Coroner completed an autopsy on the passenger on May 19, 2012. The cause of death was listed as multiple blunt force trauma due to aircraft collision with ground.

The Bioaeronautical Sciences Research Laboratory CAMI, Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot. Analysis of the specimens contained no findings for carbon monoxide or cyanide; an analysis of the specimens for volatiles, and tested drugs were not performed.

TEST AND RESEARCH

The wreckage was inspected on December 11, 2012, at Air Transport in Phoenix, Arizona. The inspection revealed no mechanical anomalies that would have precluded normal operation of the airplane or engine. Flight control continuity was established.

Airframe

The accident airplane was originally manufactured with ejection seats. In a letter dated February 8, 2010, to the FAA from the airplane owner, the owner reported that both of the ejection seats had been rendered nonfunctional; deactivated.

There were two canopies; one for the front seated pilot, and one for the rear seated passenger. Examination of the wreckage revealed that the pilot's canopy handle lever was selected to the OPEN position. The Plexiglas canopy for the pilot remained intact. The canopy seal tube remained mostly continuous with about 6 inches of the aft portion of the seal missing. The four retaining bolts for the canopy were in place and not deformed. On the left side of the canopy there were two vertical hinge points that were also intact and not deformed. When the release for the canopy was manipulated, the pilot's canopy functioned normally.

The passenger canopy (rear seat), the seal was fully intact for the entire canopy. The forward left portion of the canopy was broken with both pieces found at the accident site. The aft left side of the canopy was deformed. All four retaining bolts and the two hinge pin attachment points were undamaged. The rear canopy release handle was in the locked position and was not movable due to damage to the fuselage. It was noted that the canopy tube inflation system for both canopies had been disconnected, and it was determined that this system was disabled by recovery personnel to facilitate the removal of the canopy.

The airplanes' original pressurization systems had been modified to accommodate United States (U.S.) Nitrogen and oxygen bottles. The nitrogen valve was in the OPEN position, and all of the fittings were in place and secured. The oxygen system was also intact with all fittings in place and secured.

The wings and flap system on the accident airplane was examined. The hydraulic flap actuator was extended indicating flaps at 25 degrees, which was set to the takeoff position. The yellow manual flap indicator pin located about midspan of the top of the wing and visible to the pilot, was extended verifying that the gear was down. The flap sensor is connected to the pitot tube and once a specific airspeed has been achieved, will automatically raise the flaps; the landing gear was found in the up (retracted) position.

Engine

Examination of the engine revealed extensive damage throughout the entire engine as a result of the accident sequence and postcrash engine fire. Rock and debris were located in the engine inlet. Approximately 4 compressor blades (12 o'clock to 1 o'clock position) were noticeably damaged, with minimal damage to the remainder of the blades. Tip damage was noted to the turbine blades. The engine was manually rotated from the turbine section with no binding evident and the compressor blades were observed to move in proper rotating order. The gearbox magnetic plug was removed and did not have any debris on the tip. The throttle position indicator on the fuel control was at 86 percent. An inspection of the airplane and engine identified no mechanical anomalies that would have precluded normal operation. A detailed examination report is attached to the public docket for this accident.

Instrument panel

The following items were retained and shipped to the NTSB materials and vehicle recorder laboratories for further examination in Washington, D.C.:

Forward and Rear annunciator panels (4)

Dynon Avionics EFIS-65

G-meter

JPI 450

TS EFIS AP III-DC

Aspen Avionics EFD1000

GARMIN GPS Map 96C

The four annunciator panels and G-meter gauge we

NTSB Probable Cause

An in-flight emergency followed by a collision with terrain for reasons that could not be determined because postaccident examination of the airframe, engine, and forward and aft canopies revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.