Left unspoken

When National Transportation Safety Board investigators investigated a crash that killed 10 people, they were confronted by a terrible silence.

About 11 minutes after 9 on a Sunday morning, the 9-1-1 emergency line in Dallas, Texas began receiving a flurry of calls. The first call, less than 20 seconds after the event, on 30 June 2019, was from the control tower at Addison airport, a business aviation facility in the city’s northern suburbs. The controller had already alerted the airport fire service. He gave a calm description of an appalling sight: a Beechcraft King Air, which the controller was able to identify precisely as a 350 series, had crashed on take-off into a hangar near the runway.

As the controller spoke, black smoke billowed in the air, forming a mushroom-shaped cloud. When asked by the operator if he knew how many ‘souls were on board’ the aircraft, the controller replied, ‘I do not.’ A cascade of calls followed over the next two minutes as public-spirited Texans reported from hotels, driveways and passing cars.

Security and vehicle cameras around the airport captured the crash from several angles. The aircraft had yawed left immediately after take-off and sideslipped before rolling inverted and diving into a hangar. The two pilots and eight passengers were killed.

Despite the number of passengers, the flight was, in official terms, private. The King Air was owned and operated by a subsidiary of a family-owned business and was taking family members and friends to Florida. ‘Since the airplane was operated exclusively under Part 91, oversight by a Federal Aviation Administration principal operations inspector was not required,’ the NTSB report noted.

The pilot-in-command was aged 71, held airline transport, commercial and instructor certificates and had accumulated 16,450 hours, including 1100 hours on the King Air. He had completed recurrent training on the King Air 350 just over two months earlier, including a simulated engine failure (which was flown at a safe altitude). The instructor remembered him as professional and ‘super strong’ on his knowledge of aircraft systems. If he had a relative weakness, it was in avionics, the instructor recalled. They had spent extra time, with the aircraft connected to external power, going over avionic features.

The co-pilot was aged 28. Colleagues and acquaintances described him as ‘very, very particular’ and ‘by the book’. ‘A mutual acquaintance of the accident pilot and co-pilot stated that the co-pilot did “a great job in the right seat” and was “like a sponge” with “great flying habits”,’ the NTSB said. It emerged he was not licensed on the 300 series King Air and handled radio calls and other duties while the pilot flew.

Wreckage of the aircraft told a distinct story, mostly in the things it did not show. Positive evidence of operation at impact was found inside both engines and there was no evidence of catastrophic mechanical failure. Both aileron trim and rudder trim knobs were found, but no trim position indications could be determined for either knob. (A King Air crash in Australia in 2017 was attributed to the pilot having left the rudder trim knob in the nose-left position). It was impossible to say whether the rudder boost system had been active. And the wreckage provided no clues as to whether the autofeather system, which feathers the propeller of a failed engine to reduce drag caused by engine failure, was armed or activated during the brief flight.

Likewise, the cockpit voice recorder revealed more in its silences than words. Audio quality was excellent, despite heat and impact damage but nowhere in the period between master switch on and impact was there any recitation of a checklist. Moreover, there was no briefing on what the crew would do in case of engine failure, or any other emergency procedure. The co-pilot noted ‘airspeed’s alive,’ but, ‘the pilots did not verbalise any V speeds before or during the take-off roll,’ the NTSB found.

Among the words on the recording are the pilot’s ‘what in the world?’ just after rotation, followed by the young co-pilot’s ‘you just lost your left engine.’ The only other voices on the CVR were an exclamation by the co-pilot at the time the aircraft rolled upside-down, and an electronic intonation, repeated several times, of the words ‘bank angle!’.

The word picture provided by the pilot’s friends had in fact been frank and nuanced. A pilot friend said the accident pilot ‘was not strong on using checklists.’ Another mutual acquaintance said the accident pilot did not like to use a checklist and ‘just jumped in the airplane and went’. ‘The business partner of the accident pilot reported that he was “bad about using checklists” and that he would not use checklists as much if he was familiar with the airplane,’ the NTSB reported.

A prominent item on the before engine start and before take-off (run-up) King Air checklists is checking and setting the friction locks for the power, propellor and condition levers. There was no way to know whether this was not done, or done in silence on the doomed flight.

But thrust asymmetry, whether caused by power lever rollback or some other reason apart from engine failure, was not sufficient to explain the 20 degrees of sideslip just before the final roll began.

The NTSB concluded the pilot had responded to the emergency with left rudder input, the opposite what he should have done. After a few seconds the pilot applied right rudder but by then the King Air was rolling over and there was insufficient altitude for recovery. The NTSB determined that had the pilot initially applied right rudder input, the aeroplane would have been controllable. Instead, having slowed from 114 kt to 85 kt in its asymmetric state, the aircraft fell into the hangar.