Obsession with a waypoint

Six passengers—two adults and four teenagers—had just returned from a hunting trip and were comfortably settled in the cabin. The commercially certificated, instrument-rated pilot was accompanied in the cockpit by his 28-year-old son, who was a student pilot sitting in the right seat.

As the pilot’s son updated aircraft performance and navigation information into the flight management system, the pilot asked him to insert W95, a waypoint to avoid restricted airspace. But his son had trouble entering it, and the pilot shrugged it off. “We’ll get that later.”

At 1:34 p.m., the single-engine, turboprop airplane took off from Hyde County and climbed on autopilot, heading southwest along the North Carolina coastline.

Soon after takeoff, the son struggled again to insert the waypoint. W95—Ocracoke Island Airport located on one of the barrier islands in the Pamlico Sound—was southeast of their current flight path and just east of the restricted area. When the pilot also struggled to insert the waypoint he became irritated with the navigation system.

The weather along the flight’s route was at best marginal. An airmet issued at 1:19 p.m. was in effect for instrument flight rules (IFR) conditions with ceilings below 1,000 feet agl and visibility below 3 statute miles in precipitation and mist. These conditions were expected to continue beyond 4 p.m.

Although not on an IFR flight plan, N79NX had now entered instrument meteorological conditions (IMC). The flight was level at 3,500 feet when the pilot contacted Cherry Point Approach saying they were en route to W95, bound for MRH. He requested VFR flight following and an IFR clearance to MRH when ATC advised that the nearby restricted airspace was active.

Again, the pilot attempted to insert W95 into the flight plan but to no avail. At one point the dismayed pilot sighed, “I don’t know what I need to do. I almost want to take it all out and start from scratch.” He then added, “I’ll tell you what, we are going to have to navigate, that’s what we’re going to need to do.”

It was 1:41 p.m. when the controller warned that the flight was about to enter restricted airspace and to confirm they would stay clear. But there was no response from N79NX. The pilot was completely preoccupied with the avionics, unsure which direction to turn away from the restricted area. But it was too late. The PC–12 entered the area’s northeast corner and the pilot’s aggravation was palpable, as he exclaimed, “What in the [expletive] am I doing?”

Instead of asking ATC for vectors to exit the area, the pilot obsessed over programming, deleting, reprogramming, and activating a flight plan in the avionics. During that time, the autopilot’s selected altitude decreased to 3,000 feet and the pitch control mode changed from altitude hold to vertical speed. N79NX began to descend, its airspeed accelerated to 240 knots, and an overspeed alert sounded twice while the pilot continued trying to enter waypoints into the navigation system. The airspeed finally stabilized at 147 knots once power was reduced.

The pilot exclaimed, “I have, I have got to get a frickin’ flight plan in this thing.” Finally, he succeeded entering W95 into the system and N79NX navigated directly to the waypoint.

Automated weather at the destination was overcast conditions at 1,000 feet, 7 miles visibility with light rain and winds out of 020 degrees at 10 knots gusting to 20. When the pilot contacted ATC and requested the RNAV Runway 26 instrument approach into Beaufort, he learned the restricted airspace was still active and the controller suggested the RNAV Runway 3 or 8 approach.

The pilot opted for Runway 8 and the controller asked, “Nine-November-X-ray, did you hear me talking to you earlier? You were in the restricted area.” The pilot apologized, explaining he was trying to exit and couldn’t receive the transmission.

It’s easy to become distracted with a task that seems important. Sadly, the pilot’s fixation on a problem he could not resolve led him to ignore his duty to aviate.Planning the approach, the pilot looked for his iPad but couldn’t locate it. “This is not good. I’m way behind the eight ball....I hate it when that happens.” His son then brought up the Runway 8 approach procedure in the navigation system. But the pilot had trouble viewing the screen, as he didn’t have his glasses. Meanwhile, the restricted area had gone cold and ATC offered Runway 26’s RNAV approach, which the pilot accepted.

Moments later, the controller cleared the flight direct to the initial approach fix for Runway 26. But the pilot failed to program the fix into the flight management system, and he uttered, “I can’t get nothing on this thing that I want.” Then, there was confusion about the waypoint’s name. The pilot’s son thought it was CIGOR but the pilot thought it was CIBAG, and he asked the controller for clarification.

N79NX’s pilot still tried to program the approach when ATC asked him to verify he was direct CIGOR. He confirmed, and ATC cleared N79NX for the approach with instructions to cross CIGOR at or above 1,900 feet msl.

The agitated pilot, distracted and obsessed with programming, deleting, and activating waypoints, finally succeeded in loading CIGOR.

He did not notice that he had descended to 1,800 feet msl and the engine torque had reduced slightly from its previous setting. After capturing the altitude, airspeed began to decrease at a rate of about 1 knot per second and the pitch gradually increased about 0.1 degrees per second.

Just before 1:59 p.m., ATC asked the pilot to verify the altimeter setting as the airplane was below the minimum crossing altitude for CIGOR. The pilot adjusted the barometric pressure and read back the altimeter setting. It was N79NX’s last transmission.

Two minutes later, the airplane’s automated stall warning system activated, the autopilot disconnected, and the airplane began climbing. N79NX then turned to the right and left, rolled into a 90-degree right-banked turn, and pitched 50 degrees nose down, descending into the Atlantic Ocean’s dark depths about three miles from the coast. Sadly, everyone perished.

Analysis 

About eight months prior to the accident, the pilot reported 3,000 hours total flight time on his last medical exam and his son at that time reported 97.4 hours total flight time—of which 21 hours was in the PC–12—on his last medical exam.

Although the pilot did not obtain a weather briefing from flight service, an account with ForeFlight, associated with the airplane, viewed both departure and destination airport information. Those pages included METARs, TAFs, and other forecasts.

When the pilot and his son flew N79NX to pick up the passengers at Hyde County Airport, his son had commented, “We’re in the soup.” After landing, the pilot remarked, “All right, so...I am going to file.”

But in spite of what he had said, he did not file an IFR flight plan before departing 7W6, and N79NX climbed into IMC before it leveled off at 3,500 feet msl. At that time, visibility was 10 miles with an overcast ceiling at 2,100 feet agl.

The PC–12’s automatic flight control system is designed to activate the stick shaker warning of an imminent stall. It then automatically disengages the autopilot to provide full stick pusher activation authority to avoid the stall. The autopilot can be manually engaged after the angle of attack is reduced and the stick shaker ceases operation.

Soon after the pilot corrected the altimeter setting, the airplane’s pitch increased to 10 degrees nose up and the airspeed dropped to 109 knots. About 15 seconds later, the stall warning alert sounded, followed by the airplane’s stick shaker activating and the autopilot disengaging automatically.

The airspeed then reached a low of 93 knots, the autopilot remained disconnected, and engine power increased. All the while, the autopilot-disconnect warning sounded continuously as the pilot still fixated on programming the navigation system.

In the final seconds of the flight, the stick shaker activated again, the engine power increased to nearly full power, and the stall warning alert continued to sound. The airspeed then dropped to 83 knots, the pitch increased to 31.7 degrees, and the stick shaker and pusher activated but could not salvage the doomed flight.

It’s easy to become distracted with a task that seems important. Sadly, the pilot’s fixation on a problem he could not seem to resolve led him to ignore his duty to aviate.

Perhaps he over relied on the autopilot’s interaction with the avionics that, if properly set up, would have made the flight easy. All it would have taken was a brief delay before departure to ensure they successfully loaded the flight plan and critical waypoint into the flight management system to complete the preflight.

Because of his obsession with programming and trying to reprogram the avionics all the way to the end, the pilot didn’t notice the decaying airspeed that ultimately activated the airplane’s stall protection.

The resulting autopilot’s sudden deactivation likely startled him, and combined with his inattention to the airplane’s attitude while in IMC, the pilot finally succumbed to spatial disorientation—a gripping disconnect from reality—that resulted in his losing control of the airplane.

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