Among the three weather phenomena that get my greatest attention, thunderstorms occupy the top two slots (icing gets the third). It’s not that I’m scared of thunderstorms; rather, it’s that I respect them. I’ve been in them—on the ground—and close enough to them in the air that I understand their power and unpredictable nature. One of the last places I want to be is in an airplane in the middle of one.
My main tactic when dealing with thunderstorms is to remain in VMC. I’ll enter IMC, but only if I know what’s on the other side, based mostly on my Mk. I, Mod 1 eyeball. When approaching a group of storms, I’ll maneuver the airplane to ensure what I’m looking at is clear sky and not just some sky-colored cloud hiding an angrier one. I’ll also use my trusty Garmin 396 and its XM Wx capability to keep track of the big picture, as well as the storms’ trends: Which way are they moving, how fast, and are they growing in intensity or dissipating?
But mostly, my Plan A is avoidance. I’ve scrubbed trips when they promised several hours of nothing but dodging thunderstorms, especially at night, when I can’t see them until it’s too late. On one occasion, I left the airplane in its hangar and delayed my departure to let a squall line pass through. I used the time to catch up on my sleep and launched with crisp, clear skies all the way to my destination.
The point is thunderstorms aren’t to be trifled with, no matter what equipment we’re flying. Anyone who’s monitored a center ATC frequency when storms are about knows the airline guys do everything they can to avoid them, too, and that’s really all you need to know. Still, on those occasions when we have to deal with them, ATC is supposed to help us out when we ask for it. Usually controllers are happy to assist. As we will see, bad things happen when they don’t.
Background
On October 26, 2009, at approximately 1143 Central time, a Beech B100 King Air impacted terrain after encountering severe weather near Benavides, Texas. An IFR flight plan was filed and instrument conditions prevailed. The private pilot and three passengers received fatal injuries; the airplane was destroyed. The flight departed Uvalde, Texas, with Leesburg, Fla., as its intended destination.
Prior to departure, the pilot expressed concern about severe thunderstorms along his intended route of flight and altered to the south his planned to maneuver around the weather. During initial climb and in response to the pilot’s query, ATC told the flight, “…there is a very significant squall line between you and your destination. Not sure how you’ll get through, but we’ll work on it somehow.” The pilot responded, “All right—I sure appreciate the help.”
At 1122:23, the pilot requested a 150-deg. heading for weather. The controller subsequently cleared him to fly 120 degrees. At 1140:43, ATC asked the King Air pilot to verify his altitude of FL250. The pilot admitted getting into “some pretty good turbulence” and being at FL240, and was cleared back to FL250. At 1142:07, an expletive and propeller noise were heard on the frequency and for the next 35 seconds there was sound similar to that made by a stuck microphone.
A review of recorded radar data revealed the airplane entered a right turn toward the northwest and started to descend at 1140. The last radar return was received at 1141:46 at an altitude of 22,200 feet. The radar track went into “coast” status at 1142:55, indicating the radar system had lost track of the aircraft.
Investigation
The aircraft was found in two general areas, situated about 0.8 nm from each other. The main wreckage included the cockpit, both engines, inboard sections of each wing, both propeller systems, the fuselage, all three landing gear and the upper portion of the right outboard wing. The second area of wreckage was scattered south of the main wreckage and included the left wing’s outboard section, portions of the upper right wing, sections of the vertical stabilizer, both horizontal stabilizers, both elevators and the rudder.
The wreckage distribution was consistent with an in-flight break-up. All airframe fractures found in the second wreckage area exhibited signs consistent with overstress failure.
The aircraft’s enhanced ground proximity warning system memory module was retrieved and its data correlated with the accident sequence. At 1142:07, when the expletive and stuck microphone were heard, the airplane’s approximate groundspeed was 139.61 knots and it was descending at 3794.7 fpm. Over the next 26 seconds, the airplane’s descent rate increased to 24,111 fpm before it reached a peak descent rate of 40,398.8 fpm. The data ended at 1143:31.
National Weather Service radar data revealed the airplane entered a line very heavy to intense echoes before it began to lose altitude and reverse course. The FAA’s definition of such weather includes severe turbulence, lightning, hail likely, and organized surface wind gusts.
Upon completing its investigation, the NTSB concluded ATC services provided the accident flight were not in compliance with FAA requirements. Although the pilot requested assistance in avoiding the “squall line” noted by the controller, he did not provide the pilot with the information as required. The controller’s subsequent statement that he saw a clear area ahead of the aircraft on the 120-deg. heading was contradicted by both the recorded data and a second controller working the D-position at the time of the accident.
Probable Cause
The NTSB determined the probable cause(s) of this accident to include, “The pilot’s failure to avoid severe weather, and the air traffic controller’s failure to provide adverse weather avoidance assistance, as required by Federal Aviation Administration directives, both of which led to the airplane’s encounter with a severe thunderstorm and the subsequent loss of control and in-flight breakup of the airplane.”
There’s not much to add, except to note this accident—like so many—simply didn’t have to happen. Delaying the flight, demanding a different, more-southerly heading, and a plethora of other options were available to the pilot, including a 180-deg. turn. It’s easy to point to the controller as being the bad guy in this instance, but pilots can’t let someone fly the airplane for them. They can’t see what we’re seeing, for one. Yes, there’s a shared responsibility, but both sides failed to do their jobs.
