NTSB: Controller "should have recognized that the adverse
weather represented an immediate safety hazard"
The NTSB has released the final report on the tragic accident
that killed famed Aviator Scott Crossfield. The report summary is
attached below...
NTSB Identification: CHI06MA115
14 CFR Part 91: General Aviation
Accident occurred Wednesday, April 19, 2006 in Ludville, GA
Probable Cause Approval Date: 9/27/2007
Aircraft: Cessna 210A, registration: N6579X
Injuries: 1 Fatal.
The airplane flew into
an area of severe thunderstorms identified as a mesoscale
convective system (or "MCS") with intense to extreme intensities
during cruise flight at 11,000 feet then descended rapidly and
impacted the terrain. The on-scene investigation revealed no
preimpact mechanical malfunctions or anomalies that would have
prevented the normal operation of the airplane or its systems.
The airplane entered the severe convective weather; the pilot
then requested and received clearance from the air traffic
controller to initiate a turn to escape the weather. The airplane
was lost from radar about 30 seconds after the pilot initiated the
turn. Before the airplane entered the weather, the controller's
radar scope depicted a band of moderate to extreme weather along
the accident airplane's projected flightpath that was consistent
with an embedded, heavy-precipitation, supercell-type thunderstorm;
however, the controller did not provide the pilot with any severe
weather advisories and did not advise the pilot of the weather
depicted on his radar scope.
Although Federal Aviation Administration directives state that
controllers should give first priority to separating aircraft and
issuing safety alerts, the directives further state that
controllers should use good judgment and first perform the action
that is most critical from a safety standpoint. Review of air
traffic communications and radar data identified no air traffic
control (ATC) radar limitations, no excessive traffic, no radio
frequency congestion, and no controller workload issues that would
have prevented the controller from issuing pertinent weather
information to the accident pilot. On the basis of the controller's
workload and available resources, he should have recognized that
the adverse weather represented an immediate safety hazard to the
accident flight and should have provided appropriate advisories to
the pilot.
The pilot obtained
several weather briefings before departure. At that time, the
current weather along the route of flight showed significant
convective activity and a moving squall line, and the forecast
predicted significant thunderstorm activity along the planned route
of flight. The pilot also discussed the weather with an
acquaintance, mentioning that he might need to work his way around
some weather. On the basis of the weather information obtained by
the pilot and his comments regarding the weather, the pilot was
aware before departure that he would likely encounter adverse
weather along the planned route of flight; however, by the time the
airplane encountered the weather, the pilot had been airborne for
over an hour and had not requested any updated weather information
from air traffic controllers. The airplane was equipped with a BF
Goodrich WX-950 Stormscope, which has some ability to depict the
location and frequency of lightning strikes in the vicinity of the
airplane; however, the investigation could not determine if and how
this equipment may have been used during the flight. The airplane
was not configured to display satellite weather information on its
global positioning systems.
In October 2006, the National Transportation Safety Board issued
Safety Alert SA-11, "Thunderstorm Encounters," as a result of this
accident and three other fatal accidents that involved in-flight
encounters with severe weather. The safety alert addresses ATC
involvement in these accidents. The alert also states that IFR
pilots need to actively maintain awareness of severe weather along
their route of flight, and it provides suggestions to assist pilots
in avoiding involvement in similar accidents.
The National Transportation Safety Board determines the
probable cause(s) of this accident as follows:
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.