Ice accumulation blamed in Montrose Challenger crash

 - September 20, 2006, 7:02 AM

The chartered Bombardier Challenger 600 sat on the ramp at Montrose Regional Airport in Colorado for 40 to 45 minutes on Nov. 28, 2004. Snow was falling and the temperature was below freezing. The jet had flown from Van Nuys, Calif., to Montrose, where actress Susan St. James got off the airplane. Her husband, NBC Sports chairman Dick Ebersol, and two sons were continuing on to Indiana.

When the Challenger took off from Montrose, Ebersol saw slush flying from the top of the fuselage. After the accident, other witnesses came forward to say they had spotted ice and snow on the Challenger. The crew had not de-iced the airplane.

Sixteen minutes before takeoff, the captain and the first officer discussed whether the wings looked clear. FAR 135.227 requires, however, that a pre-takeoff contamination check must be completed within five minutes before takeoff if conditions are conducive to such contamination. (The NTSB concluded that
the crew’s pre-takeoff discussions also revealed several crew resource management [CRM] deficiencies as well.)

The jet stalled and lost roll control shortly after liftoff. The airplane did not climb, said the NTSB, but rolled violently left and right several times before it hit the ground. The Safety Board released its determination of probable cause May 2, blaming the accident on the pilot’s failure to detect and remove ice and snow on the wings of the jet.

The upper-wing contamination, said the Board, caused the subsequent stall and crash. A factor was the crew’s lack of experience in winter weather conditions. The captain, the flight attendant and one passenger–Ebersol’s teenage son–were killed. Ebersol, the copilot and another passenger–Ebersol’s other son–were seriously injured. The airplane was destroyed by the impact and subsequent fire.

As a result of its investigation into the Montrose accident, the NTSB recommended that the FAA develop visual and tactile training aids showing small amounts of contamination on upper wing surfaces, then require all commercial operators to incorporate the aids into their training programs. The Board repeated its recommendation that the FAA require Part 135 on-demand charter operators that use two pilots to develop and implement an FAA-approved crew resource management training program.

Just after the Challenger accident, the Safety Board warned, “Research has shown that small amounts of ice accumulation on the upper surface of a wing can result in aerodynamic degradation as severe as that caused by much larger (and more visible) ice accumulations.”

On Feb. 17, 2005, the FAA issued AD 2005-04-07 for all CL-600-series Challengers and CL-600-2B19 CRJs requiring the revision of airplane flight manuals to include a new cold-weather operations limitation–a tactile check, as well as a visual check, must be done to determine that the wing is free from frost, ice, snow or slush when certain weather conditions exist.

The agency reiterated the Safety Board’s alert about accumulation and reminded operators that even small amounts could cause “an adverse change in the stall speeds, stall characteristics and the protection provided by the stall-protection system.”

The Board also recommended that the Department of Transportation require that operators of air-taxi flights inform customers and passengers of the name of the company with operational control, including any “doing business as” (dba) names used, the aircraft owner and the name(s) of any brokers arranging the flight. The Challenger involved in the Montrose accident was registered to Hop-a-Jet and operated by Air Castle, dba Global Aviation as Glo-Air Flight 73.