Not all that long ago, flying in thunderstorm weather was more of an art than a science. Weather radar hadn’t been invented; the only real technology available was to use the ADF and avoid areas to which its needle pointed. Grizzled veterans with years of experience flogging DC-3s across the Great Plains had developed their personal methods for dealing with them. Too often, those methods allowed penetration—sometimes at low levels, maybe at higher ones—and didn’t stress avoidance.
These days, a pilot with a fraction of the experience those captains had is favored with many more tools with which to locate and avoid convective weather. In heavy-iron operations—and even smaller ones—extremely capable airborne weather radar is the norm. Even flivver drivers can access satellite- or ground-based Nexrad weather radar imagery for not much in the way of expensive hardware or subscriptions. The Nexrad option also affords pilots the ability to scroll well beyond an airborne radar’s range to look at conditions they won’t encounter for hours, if ever, in near-real-time.
As with any tool, however, there’s a right way and a wrong way to use airborne Nexrad and other weather-finding options. Even those pre-war DC-3 captains knew enough to circumnavigate thunderstorms while some pilots today seem to think having all the bells and whistles in their cockpits makes them bulletproof. It ain’t so, and Nexrad’s characteristics—including what can be a lengthy lag between the observed weather and when the radar imagery appears in the cockpit—recently were highlighted by the NTSB as a factor in at least two fatal general aviation accidents. This is not one of them.
History
On October 26, 2010, at about 0954 Central time, a Beech Model B36TC Turbocharged Bonanza was destroyed following an in-flight break-up and collision with terrain while in cruise flight near Rienzi, Miss. The instrument-rated private pilot and passenger were killed. Instrument conditions prevailed; the airplane was operating on an IFR clearance.
An hour earlier, at about 0900, the pilot called Flight Service to file an IFR flight plan. During the conversation, the briefer asked the pilot if he needed the latest adverse weather conditions. The pilot replied, “No, that’s why we are getting out of here.”
Radar data depicted the accident airplane climbing to 14,800 feet. The last three radar targets—each of which were 10 seconds apart—displayed altitudes of 14,800, 14,700, and 13,900 feet. At this point, radar contact was lost. Interpolation of the last two radar targets suggested a 4800-fpm descent rate. At the time the radar target was lost, the airplane was in an area of depicted extreme-intensity precipitation.
Investigation
It took three days of air and ground searches to find the wreckage, which was scattered over an area approximately 15 miles in length. Parts not located included the right aileron, vertical stabilizer, rudder, horizontal stabilizers, left elevator and the outboard portion of the right elevator.
All fractures and failures were consistent with overload failure induced by air-load or impact. All control cable, chain, bellcrank and pulley failures were consistent with overload. The right wing leading edge contained diagonal compression buckling in the upward direction. The fuselage structure was not attached to the aft cabin floor, and skin tearing signatures were visible on both lower longitudinal skin lap joints (left and right side) throughout its length.
According to records dated July 14, 2007, repairs “due to stress” were completed on the accident airplane. Some of the parts replaced included left and right-hand stabilizer assemblies, the left and right-hand wing skins, and belly skin. According to the repair facility, this was the second airplane the pilot/owner had brought to him for repair after flying through “heavy” weather. The first airplane wasn’t repairable; the second airplane was brought to the facility no more than 30 days later. When the pilot arrived with the second, accident airplane for repair, he announced, “I did it again.”
At 0959, weather conditions reported 13 miles northeast of the accident site included scattered clouds at 600 feet, a broken ceiling at 2600 feet, and an overcast ceiling at 3900 feet, with two miles’ visibility. Temperature was 26 deg. C, dewpoint 23 deg. C and an altimeter setting of 29.66 inches of mercury. Winds were from 210 degrees at 14 knots.
The pilot subscribed to a satellite weather service, which could display Nexrad weather imagery on panel-mounted avionics. At the time of the accident, radar data depicted a line of thunderstorms crossing the airplane’s route of flight in the vicinity of the crash site. Level 5 and 6 radar echoes—intense and extreme—were recorded in the area at the time of the accident.
A review of recorded ATC radar track and precipitation information showed the aircraft’s flight path approached and entered an area depicted as heavy to extreme precipitation. The controller passed along a Pirep to the accident flight noting light turbulence and about a minute’s heavy rain provided 20 minutes earlier, 5000 feet lower and several miles north of the point where radar contact was lost. No other information was provided to the pilot about the precipitation depicted on the controller’s display.
Probable Cause
The NTSB determined the probable cause(s) of this accident to include: “The pilot’s continued flight into known adverse weather conditions. Contributing to the accident was the air traffic controller’s failure to provide precipitation information to the pilot as required.”
It’s difficult to determine what was going on in this pilot’s mind when it came to penetrating intense thunderstorms. Not only did the pilot fly this airplane into known heavy weather, he had a habit of it, as the two previous examples demonstrate. Since the second time merely resulted in a replacing major airframe components instead of a totaled airplane, we’re left to wonder if he thought he was getting the hang of it.
No airplane is fully armored against extreme weather and piston singles are perhaps least capable of penetrating thunderstorms. But despite all his history and apparent full knowledge of the weather he was about to fly into, this pilot did it anyway. Most of us would never have gotten close to that storm system. For the rest of us, once would have been enough. But three times, that we know of?
