Thunderstorm avoidance is a perennial topic among GA pilots. There are all kinds of tips and equipment recommendations thrown about, including suggestions on how to use and interpret both airborne and data-linked Nexrad weather radar, plus sferic devices and, we suppose, animal entrails, powdered unicorn horns and coin flipping. All methods pretty much depend on a pilot actively seeking information, processing it and reacting to what is learned. As we detailed in last months feature article,
One of the first keys to thunderstorm avoidance is actively seeking out all available information. This can include querying controllers about what they may know about the weather, what their radar indicates, what other aircraft are doing. Once all available information is retrieved-and well be the first to suggest “all available information” may not add up to much-then and only then can a decision be made to proceed into an area of weather.
Too often, though, pilots either dont seek ATCs input or, since controllers are supposed to inform pilots about convective weather, presume no news is good news. We dont know exactly what occurred before aviation legend Scott Crossfield died after flying into a thunderstorm, but we do know the NTSB, in part, faulted the controller for failing “to provide adverse weather avoidance assistance” on April 19, 2006, less than a month before a similar accident.
BACKGROUND
On May 10, 2006, at 0921 Central time, a Piper PA60-602P broke up in flight in the vicinity of Camp Hill, Ala., while maneuvering to reverse its flight path in an intense thunderstorm. Instrument conditions prevailed. The airplane was destroyed. The private pilot and one passenger received fatal injuries. The flight originated about an hour earlier from Habersham County Airport, Cornelia, Ga., on May 10, 2006, at 0919 Eastern time.
A person identifying himself as the accident pilot telephoned Macon Automated Flight Service Station (AFSS) earlier to request a weather briefing. He was provided information on a line of embedded thunderstorm activity along his proposed route to Mobile, Ala., which included SIGMETs. Instead of filing to Mobile, the pilot filed a flight plan for Pensacola, probably with the intent to land and wait out the storms. The pilot departed without an IFR clearance and contacted Atlanta ARTCC at 0929 Eastern time.
Almost 45 minutes later, the Atlanta ARTCC broadcast Center Weather Advisory 101, which concerned a line of thunderstorms 40 nm wide, moving from 280 degrees at 35 knots. The weather alerts included the accident aircrafts route of flight.
Radar data revealed the airplane was at 16,000 feet msl, heading southwest at 09:19:48 Central time. At 09:20:38, it began a continuous left turn to the northwest at 15,700 feet. The last radar return was at 09:20:59; the airplane was at 15,600 feet.
Investigation
A weather study conducted by the NTSB Meteorology Resource Specialist revealed the pilot penetrated an intense to extreme VIP level 5 to level 6 weather radar echo containing a thunderstorm.
Examination of the crash site revealed the airplane collided with trees and the ground in a vertical, nose-down attitude. The airplane came to rest on a heading of 355 degrees magnetic. No crash debris line was noted. Among other structural damage, the outboard right wing panel had separated 9 feet 2 inches from the wing root. The deformation patterns were consistent with upward bending overstress of the right wing. The separated outboard section of the right wing was not recovered. Both engines were buried three feet in the ground.
Examination of the airplanes radar ground track revealed no course deviations until the pilots attempt to turn around. The recorded weather display data showed the storm was straight ahead of the airplane for several minutes before the pilot told ATC he needed to reverse course. The three controllers did not provide any radar weather information to the pilot as required.
Probable Cause
The National Transportation Safety Board determined the probable cause(s) of this accident to include, “The pilots continued flight into known thunderstorms resulting in an in-flight break up. A factor in the accident was air traffic controllers failure to issue extreme weather radar echo intensity information displayed on the controllers radar to the pilot.” The NTSBs probable cause statement is remarkably similar to the one associated with Scott Crossfield.
Both the accident pilot and ATC knew there were thunderstorms along the Aerostars route of flight. Why there was no discussion of them-regardless of who initiated it-is a mystery, especially since its likely anyone listening to the ATC frequency and the probable deviation requests would have been aware there was significant weather in the area. To make it official, a Center Weather Advisory also was broadcast.
We dont know how the accident aircraft was equipped; did it have airborne weather radar? Was datalinked Nexrad available in the cockpit? Did the pilot intend to avoid the storms by landing at Pensacola? Why didnt he query ATC about the storms position, ask for vectors, seek information on what other flights in his vicinity were doing or whether a clear route was available? Was he counting on ATC to keep him out of the bad stuff? Well likely never know.
What we do know is neither side of the mic requested or provided information that might have resulted in a timely deviation or 180-degree turn. Either both sides were waiting on the other to offer up something, or neither was clear on the roles to be played. That a pilot would knowingly launch toward an area of thunderstorms and then not display any inquisitiveness about them is disturbing. So is ATCs failure in this instance.
Also disturbing is the track record the Atlanta ARTCC established in the spring of 2006 on advising pilots about to fly into intense weather. Lets hope theyre better at it now, and pilots know not to wait for ATC to tell them about thunderstorms.
