NTSB Factual Report

HISTORY OF FLIGHT

On May 4, 2014, about 1359 Pacific daylight time, a Boeing E75, N68828, was destroyed when it impacted runway 21R during an aerial demonstration flight at Travis Air Force Base (SUU), Fairfield, California. The commercial pilot/owner received fatal injuries. The exhibition flight was operated under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the flight.

The pilot was one of several civilian aerial demonstration pilots who performed at the 2-day SUU "Thunder Over Solano" open house, which included both static (ground) and aerial (flight) displays. According to United States Air Force (USAF) and Federal Aviation Administration (FAA) information, Friday, May 2, was the practice day, while the public event took place on Saturday and Sunday, May 3 and 4. The pilot flew two flight demonstration airplanes at the event; a North American P-51, and the accident airplane. All his flights preceding the accident flight were uneventful.

The accident occurred during a "ribbon-cut maneuver," whereby a ribbon was suspended transversely across the runway, between two poles held by ground crew personnel, and situated about 20 feet above the runway. The planned maneuver consisted of a total of three passes. The first two passes were to be conducted with the airplane upright, and were not planned to contact the ribbon. The final pass was to be conducted inverted, and the airplane would cut the ribbon with its vertical stabilizer. The first two passes were successful, but on the third (inverted, ribbon-cut) pass, the airplane was too high, and did not cut the ribbon. The pilot then initiated a fourth pass, and rolled the airplane inverted after aligning with the runway. The airplane contacted the runway prior to reaching the ribbon, slid inverted between the ground crew personnel holding the ribbon poles, and came to a stop a few hundred feet beyond them. A fire began as the airplane stopped. The pilot did not exit the airplane, and was fatally injured.

PERSONNEL INFORMATION

The 77-year-old pilot was a well known air show performer in the western United States. FAA records indicated that the pilot held a commercial pilot certificate, with single- and multi-engine airplane, and instrument airplane ratings, and was authorized to fly several experimental airplanes. His most recent FAA second-class medical certificate was issued in June 2013; on that application the pilot indicated that he had a total civilian flight experience of 11,400 hours.

AIRCRAFT INFORMATION

FAA information indicated that the airplane was manufactured in 1944, and was first registered to the pilot in 1982. The airplane was equipped with a Pratt & Whitney R-985 series engine. The fuselage and empennage consisted of a synthetic-fabric covered steel tube structure, while the wings were primarily wood structure covered with the same type of fabric. The airplane was equipped with two tandem cockpits enclosed by a single canopy; the pilot flew the airplane from the aft cockpit.

The canopy consisted of a light metal frame (aluminum and steel) and plastic transparencies. The canopy was not part of the original airplane design or configuration. According to maintenance record information, and information provided by the pilot's family, the canopy was designed by the pilot with help from Serv Aero in Salinas, California. It was a modified version of the canopy from a "Varga" airplane, and had been installed on the accident airplane in November 1985. The canopy was intended to "improve air flow over the elevator and rudder for better flight control," and to provide additional cockpit comfort, in terms of reduced noise and wind blast.

The longitudinal section of the canopy consisted of one fixed panel (right side) and two movable panels (top and left side). The top panel was longitudinally hinged to the fixed right panel and the movable left panel, and the forward and aft bottom corners of the left panel rode in transverse tracks at the forward and aft ends of the cockpit. That design allowed cockpit entry and egress by operating the top and left canopy panels in a manner similar to a bi-fold door; which required approximately 18 inches of clearance above the canopy for the canopy to be opened.

The 47-gallon aluminum fuel tank was mounted in the center section of the upper wing, just forward of the cockpit. The main fuel tank was equipped with a central filler neck with a cap that protruded about 1.5 inches above the tank upper mold line. Four non-metallic flexible fuel lines, one near each lower corner of the main tank, enabled fuel to be supplied from the main tank.

An aluminum header fuel tank, of approximately 3 gallons capacity, was mounted in the fuselage forward of the cockpit. An oil tank for smoke generation was mounted below and slightly aft of the header tank.

METEOROLOGICAL INFORMATION

The SUU 1358 automated weather observation included wind from 240 degrees at 15 knots gusting to 21, visibility 10 miles, few clouds at 18,000 feet, temperature 22 degrees C, dew point 12 degrees C, and an altimeter setting of 29.99 inches of mercury.

COMMUNICATIONS

SUU was equipped with an air traffic control tower (ATCT) that remained staffed and operational during the air show. However, during certain portions of the show, the ATCT ceded control of some of its designated airspace (and the aircraft within) to the air show "air boss." The Air Boss was defined by the FAA as the "individual who has the primary responsibility for air show operations on the active taxiways, runways, and the surrounding air show demonstration area." For this particular event, the Air Boss was a civilian who was well acquainted with the performers, performances, and overall show schedule. The Air Boss and pilots communicate directly with one another via radio. The ATCT and air boss coordinate closely to ensure continuous control of the airspace before, during, and after the show.

In response to an NTSB question, the USAF stated that the "Air Boss turned over control of the airspace to tower and RAPCON [radar approach control] once airborne traffic was assigned to designated holding area behind the crowd. Tower/ground control managed access into the controlled movement area during the emergency response period via existing protocols. This was briefed at every safety brief before each day of flight, and the actual execution after the mishap followed the briefed plan."

According to the transcript of radio communications between the ATCT, the Air Boss, and aircraft, the first indication of the accident was at 1357:56, when the Air Boss transmitted "Tower, tower, tower, we need to, emergency trucks, roll em out, roll em, roll em, roll the emergency trucks." At 1358:02, an unknown person transmitted "alright," which was followed at 1358:04 by the Air Boss transmitting that he had the "airspace closed for the fire." The transcript did not include any communications regarding that reported closure.

At 1358:14, the ATCT controller transmitted "Tower's got the airspace," followed by the Air Boss 1358:15 transmission of "you got the airspace, you got the field, they are up and moving." At 1358:18, the ATCT transmitted "Roger, we got em rolling."

At 1359:01, the Air Boss asked "tower we got the trucks rolling?" to which the ATCT responded "affirmative and they're coming out to you on the runway now." At 1359:02, an unidentified person transmitted "Air Boss we need fire immediately he is trapped in the airplane and on fire." That discussion continued almost another minute.

At 1401:41, the ATCT transmitted to the Air Boss, who was attempting to land one of the airborne performers, to have that airplane go around, because "responder vehicles just turned on [to runway] two one left." At 1401:57, the ATCT informed the Air Boss that they would advise him when the runway was clear. No further communications regarding the ARFF vehicles or their clearance of the runway were included in the transcript, which ended at 1402:53.

Based on this transcript, the first ARFF vehicles entered the runway about 3 minutes 45 seconds after the first radio transmission announcing the accident.

AIRPORT INFORMATION

The airport was equipped with two primary runways. The two runways, designated 3/21R and 3R/21L were staggered such that the approach end of 3R was adjacent to the approach end of 21R. Runway 3l/21R was the primary air show performance runway, and measured 150 by 11,001 feet.

The static displays and spectator areas were situated on the northeast ramp area, northwest of runway 21R. The spectator area was situated about 1,000 feet from the northwest edge of runway 21R.

The air show "performance (or aerobatic) box" measured about 3,000 by 12,000 feet, and was situated on the northeast section of 3L/21R. Air show center was located approximately 1,200 feet beyond the threshold of runway 21R.

WRECKAGE AND IMPACT INFORMATION

The airplane impacted runway 21R. Ground scars consisted of rudder/ vertical stabilizer ("tail") and upper wing contact (metal and wood scrapes, and paint transfer) with the runway, as well as propeller "slash marks" approximately perpendicular to the direction of travel. Review of image and ground scar data indicated that the airplane first contacted the runway with its right wing, followed by the tail, the left wing, and then the propeller.

The upper outboard right wing initial scar was followed about 7 feet later by the tail strike, and then a few feet later by the upper left wing. The initial tail strike was located about 45 feet right (northeast) of the runway centerline, about 380 feet beyond the runway threshold. The initial direction of travel was aligned approximately 5 degrees to the right (divergent from) the runway axis. The propeller slash marks began about 100 feet beyond the initial tail strike, and continued to the final resting location of the airplane. The slash marks described an arc, which curved to the left. The airplane slid inverted, and traveled a total distance of about 740 feet. It came to a stop near the left (southwest) edge of the runway, on a magnetic heading of about 140 degrees. Review of still and video imagery revealed that the airplane came to a stop about 13 seconds after it contacted the runway.

Examination of the wreckage indicated that most of the fabric covering on the fuselage was damaged or consumed by fire. The right wing and cockpit furnishings were almost completely consumed by fire, as were some of the aluminum flight control tubes. The left wing and rudder /vertical stabilizer sustained impact deformation, but the cockpit occupiable volume was not compromised by deformation of any surrounding structure.

The fuel lines and the main fuel tank were fire damaged, and at least two thermal penetrations of the main fuel tank were observed; both were consistent with an on-ground fire. The main tank fuel cap was found installed and latched. The cap/neck and surrounding tank skin appeared to be depressed slightly into the tank, but it could not be determined whether the cap and neck leaked fuel after the impact. No evidence of any provisions for increased crashworthiness of the fuel system, such as frangible, self-sealing line couplings, was observed in the wreckage. Due to the level of damage, the investigation was unable to determine the initial source(s) of the fuel that resulted in the rapid growth of the fire.

Still and video images of the accident sequence, combined with on-scene observations, revealed that partial collapses of both the upper wing and the vertical stabilizer and rudder assembly, due to ground contact, resulted in the clearance between the top of the canopy and the runway surface being too small to allow the canopy to be fully opened. The canopy opening geometry was such that the relationship between the vertical travel of the canopy top and the actual opening provided was not linear; a small reduction in the vertical travel capability of the canopy top would result in a significant reduction in the size of the opening it afforded for cockpit egress. The canopy was not equipped with any emergency egress provisions, such as quick-release hinge pins.

All components, with the exception those consumed by fire, were accounted for. No evidence of any pre-impact engine or flight control problems was noted, and no evidence consistent with any pre-impact abnormalities or deficiencies that would have precluded continued flight was observed.

MEDICAL AND PATHOLOGICAL INFORMATION

In response to NTSB questions, the pilot's family reported that they were "not aware of any unusual or abnormal issues with either the pilot's sleep patterns before the accident or with the aircraft or the aircraft's maintenance or condition. The pilot was not ill and the family is not aware of any stressors." The family reported that his physical health and mobility was "good," and that he "was quite capable of climbing in and out of both the Stearman and the P-51." They described his mental acuity and awareness as "excellent."

In his most recent application for an FAA second-class medical certificate, the pilot reported high blood pressure, treated with amlodipine and hydrochlorothiazide. The pilot was issued that certificate with unrelated limitations regarding corrective lenses for vision.

The Solano County California County Coroner determined that the cause of death was extensive thermal injury. The pathologist did not identify evidence of blunt force trauma.

Toxicology testing performed by the FAA's Civil Aerospace Medical Institute did not identify levels of carbon monoxide above 10%. Testing identified amlodipine in heart blood and liver tissue. Cetirizine was detected in the heart blood, but below quantifiable levels. Cetirizine is a sedating antihistamine used to treat allergy symptoms, marketed under the brand name Zyrtec.

Toxicology testing also detected Diphenhydramine in the heart blood and urine. Diphenhydramine is a sedating antihistamine used to treat allergies, cold symptoms, and as a sleep aid. It is available over the counter under various names such as Benadryl and Unisom. Diphenhydramine undergoes postmortem redistribution to the heart blood. As a result, postmortem heart blood diphenhydramine levels may be increased by about a factor of three. The measured diphenhydramine level, when divided by three, was still within the therapeutic range.

FIRE

Review of video and still images revealed that fire became visible just as the airplane stopped moving, and some patches of fire were visible on the ground along an apparent fuel trail aft of the airplane. Once the airplane came to a stop, the fire appearance was initially consistent with a "pool fire," which is the combustion of a liquid pooled on the ground. However, the fire enlarged quickly, and within about 50 seconds, the fire encompassed most of the right (downwind) side of the airplane. The airplane was completely engulfed by the fire about 1 minute and 32 seconds after the airplane stopped.

Review of the still and video imagery, and the wreckage, indicated that at first the fire was consistent with liberated gasoline spilled on the ground, but the fire developed rapidly thereafter. It began consuming the airplane skin and structure, and damaged the fuel lines and tanks, which permitted the liberation of additional onboard flammable fluids, including gasoline and oil.

Review of photographic and other documentation indicated that the flames were no longer visible about 5 minutes and 17 seconds after impact, or about 15 seconds after truck-provided fire fighting agent began contacting the fire. USAF information indicated that the fire was "knocked down" (significantly reduced) about 6 minutes and 38 seconds after it started, and that it was extinguished about 9 minutes after it started. The fire-fighting activities are detailed in a separate section below.

ADDITIONAL INFORMATION

Survival Aspects

According to information provided by first responders, after the fire was extinguished, the pilot was observed to be within the cockpit, lying on his back on the upper canopy frame, with his head towards the tail. The airplane fuselage had settl

NTSB Probable Cause

The pilot’s failure to maintain clearance from the runway during a low-level aerobatic maneuver due to his impairment by an over-the-counter antihistamine. Contributing to the severity of the pilot’s injuries were the pilot’s lack of fire protective clothing, his inability to egress the cockpit, the rapid spread of the fire, and the decision of the air show’s organizers not to have the airport rescue and firefighting services at their highest level of readiness, which delayed arrival of fire suppression equipment.