Famed pilot Scott Crossfield’s last words on 19 April 2006 were mundane. “Atlanta, this is seven niner x-ray, I’d like to deviate south weather,” he transmitted. The controller replied, “Six five seven niner x-ray, roger, we’ll show you deviating south for weather, and your Mode C [transponder] indicates one one thousand five hundred.”

Crossfield did not respond. The wreckage of his Cessna 210A was found the next day in remote mountainous terrain.

Before departure from Prattville, Alabama, Crossfield discussed the weather with an acquaintance and mentioned that he “might have to work his way around some weather [during the flight to Manassas, Va.], but it did not look serious.”
The air traffic controller was interviewed after he crash by National Transportation Safety Board (NTSB) investigators. According to the report of investigation:

"[The] controller acknowledged that adverse weather was present ‘all over’ his sector with varying intensities. The controller stated that northbound departure … were encountering adverse weather and were ‘picking their way through holes in the weather.’ He acknowledged that controllers are required to issue known adverse weather to pilots. The controller also stated that his scope depicted adverse weather in the airplane’s projected flight path. The displayed weather included all three levels of precipitation (moderate, heavy, and extreme). The controller said that, even though the adverse weather was throughout the area, he did not issue the information to the pilot because he felt that the weather conditions displayed on his radar scope were unreliable. The controller believed that the displayed weather can be between 6 and 15 minutes old and is widely viewed as being unreliable. He stated that pilots have a better idea of where adverse weather is and that he expects them to inform him on what actions they need to take to avoid it. By not issuing weather reports to the pilot, the controller violated several paragraphs in FAA Order 7110.65, ‘Air Traffic Control.’ ”

As a consequence, the NTSB issued a dual finding of blame in the probable cause of the accident:

“The pilot’s failure to obtain updated en route weather information, which resulted in his continued instrument flight into a widespread area of severe convective activity, 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 subsequent loss of control.”

A lookalike Cessna 337 crash in 2005 prefigures the Crossfield tragedy, and in that case the NTSB issued a probable cause that similarly faulted the inaction of the air traffic controller:

“The pilot’s continued flight into an area of known convective weather, resulting in loss of aircraft control. Contributing factors were the failure of the FAA center controller to provide information on depicted severe weather to the pilot and the controller’s delay in providing requested navigational assistance until it was too late to provide the pilot with effective assistance in avoiding severe weather.”

In October 2006, six months after the Crossfield accident, the NTSB issued a Safety Alert on “Thunderstorm Encounters” advising that “IFR [instrument flight rules] pilots need to actively maintain awareness of severe weather along their route of flight.”

Although waxing eloquent for three pages about what pilots should do, the alert had precious little to say to controllers, other than, “ATC training and briefing to controllers have not been sufficient to ensure that pilots receive the weather advisories needed to support good in-flight weather avoidance decisions.”

Well and good, but it would seem appropriate for the NTSB to say more to controllers, given that they play a central role in IMC weather avoidance. (For the Crossfield accident report, see www.ntsb.gov/ntsb/brief.asp?ev_id=20060501X00494&key=1; for the earlier accident, see www.ntsb.gov/ntsb/brief2.asp?ev_id=20051028X01748&ntsbno+MIA06FA008&akey=1; for the Safety Alert, see www.ntsb.gov/alerts/SA_011.pdf)