The Dassault Falcon 50 registered as N114TD was manufactured by Dassault-Breguet in 1984 and was 34 years old at the time of the fatal accident at Greenville Downtown Airport (KGMU) on Sept. 27, 2018. The airplane had 14,013 total hours and 7,541 cycles prior to the accident. According to the operator's director of maintenance (DOM), the airplane had been kept in storage in a hangar for about four years. In June 2018, three months before the accident, the operator began a plan to return the airplane to airworthy condition. Because of the length of time the airplane had been out of service, the work to be done was extensive.

Except for an avionics check conducted the month before the accident, no required checks had been done since 2014, and some were last done in 2007. A required 72-month inspection of the landing gear had not been done since 2012, and the last overhaul of the landing gear, which is required every 12 years, had not been done since 2002.

The initial work order created to return the airplane to service listed 103 discrepancies or inspections to be addressed. The DOM said he thought about 60% of those items had been completed at the time of the accident. An item to send out an anti-skid control valve for overhaul had not been accomplished.

The operator of the accident flight, Air America Flight Services, held an FAR Part 135 Air Carrier certificate for on-demand operation issued by the FAA in 2000 and amended in 2005. Three airplanes were listed in the operations specifications: a Beechcraft Super King Air BE-200-200, a Dassault Falcon AMD-50-50 and a Piper Aircraft Chieftain PA-31-350. The operator was authorized to use a minimum equipment list (MEL). Inoperative systems permitted under an MEL are typically brought to the attention of the pilot by a logbook entry and a colored sticker placed near the activating switch of the affected system.

In an interview, the DOM said the FAA principal maintenance inspector (PMI) for Air America Flight Services had not been on the premises since 2017.

The 49-year-old PIC had an Airline Transport Pilot (ATP) certificate for single-engine and multiengine land and reported having 11,650 total flight hours. He had type ratings in Learjet and Westwind models. His type rating in the Falcon 50 was limited to second-in-command (SIC) only. His recent flight experience and experience on type was not reported.

The copilot, who was 66 years old, held a private pilot certificate with ratings for airplane single-engine and multiengine land. He did not hold any type ratings or an instrument rating. He had 5,500 hr., but his recent experience was not reported. He was also the owner of Air America Flight Services. Two of his sons worked for the company, and one was the DOM.

Based on their pilot certificates, neither pilot was qualified to be at the controls in their respective seats on the accident flight.

An investigator interviewed a pilot who had flown N114TD as PIC four times in the month before the accident. He said he had flown maintenance test flights at St. Pete-Clearwater International Airport (KPIE), Florida, in the airplane at the end of August and again in early September. In both cases the normal brakes would work at 15- to 20-kt. taxi speed but would not work above that speed. The emergency brake system did work when the brake switch was set to “#2/OFF.”

Informed that the brake issue had been repaired, the pilot flew the airplane from KPIE to Cleveland-Hopkins International Airport (KCLE) on Sept. 22 and back to KPIE on Sept. 23, 2018. On both flights, he had again experienced no braking with the normal system during landing and he had switched to emergency brakes to stop the airplane.

On all four flights, his copilot was the owner of Air America Flight Services. The pilot said he was not aware that his copilot was not qualified in the airplane.

Conclusions
The NTSB determined that the probable cause of the accident was “the operator's decision to allow a flight in an airplane with known, unresolved maintenance discrepancies, and the flight crew's failure to properly configure the airplane in a way that would have allowed the emergency or parking brake systems to stop the airplane during landing.”

Safety board investigators did a good job of finding out the technical reasons for the brake malfunction and they properly found operator decisions and crew actions to be the cause of the accident. They did not quite penetrate the personal and family dynamic going on between the pilots and mechanics involved. For example, the DOM said the fact that his father took the airplane without consulting him “was a source of friction between us.” The reasons the pilots took the actions they did aren’t clear, and we are left with some unanswered questions.

Why did the company owner believe that the normal brakes would work despite all evidence to the contrary? Why did he not move the brake system switch to “#2/OFF” after landing when it became apparent the normal brakes were not working? Why did the pilot who flew the last four flights before the accident decide not to fly on the date of the accident? Why did the new PIC accept the inversion of the normal command gradient between the pilot-in-command and his copilot? Why did that pilot not ask pointed questions about the MEL sticker on the brake switch, and why did he not just request an ILS approach to the other runway at Greenville when he found out the airplane was not RNAV-capable?

We can guess at the answers to these questions, but we don’t know for sure.

A friend of the company owner was quoted in a local newspaper as saying that the owner loved aviation and wanted to leave his charter company as a legacy to his sons. Unfortunately, as a result of his actions, the company had to surrender its Part 135 certificate a few days after the accident.

When the NTSB finds new safety issues, it writes recommendations to address them. The board wrote no new recommendations in this case. The requirement for PICs to ensure the airworthiness of their aircraft and to be familiar with all available information about their planned flights is already stated in FAR Part 91.7 and 91.103. The fact that the PIC of a turbojet aircraft must be fully type=rated is already a requirement under Part 61.31.

The two people who are entirely free of culpability for this imminently avoidable accident are the severely injured passengers. They had a right to believe that when the FAA certified the operator for Part 135 operation, they could expect the company to observe all the rules put in place to ensure their safety. They found out that sometimes the FAA does not remove a Part 135 certificate until after an accident happens.

If there is a lesson to be learned from this accident, it is one for charter passengers. Careful due diligence is a must before they choose a charter operator.

See Unable To Stop, Part 1, Falcon 50 Brake Malfunction, at https://aviationweek.com/business-aviation/unable-stop-part-1-falcon-50-brake-malfunction