Contributor - Business Aviation

Rob Finfrock

Improper crew response to an off-center nosegear orientation was the primary factor in the July 2012 fatal runway excursion of a Gulfstream IV at Le Castellet Airport on the French Riviera, according to a<a href="http://www.bea.aero/docspa/2012/n-ga120713.en/pdf/n-ga120713.en.pdf"> final report</a> released last month by the French Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA). The aircraft was operated by Universal Jet Aviation of Boca Raton, Fla. The accident claimed the lives of all three people on board–the two pilots and one cabin attendant.

 


According to the report, the crew of N823GA flew a visual approach to Runway 13 (5,741 feet by 98 feet) at Le Castellet Airport, with the airport reporting a light crosswind from the right. The aircraft’s main gear first touched down about 1,200 feet from the approach threshold, with the nosewheel first alighting 2,525 feet down the runway. The aircraft’s nose then pitched up and veered slightly right of centerline. The pilots corrected with left rudder input and applied “strong nose-down input” to return the nosewheel to the pavement.

 


Investigators noted that after the second touchdown sensors on the nosegear recorded “unusually heavy loading” on the assembly for less than a second, followed by a nosewheel orientation to the left that exceeded the seven-degree maximum available through use of the rudder pedals. Investigators could not determine if the left-seat pilot attempted to use the tiller to command greater steering control, although they noted the switch to engage the tiller remained in the off position throughout the accident sequence.

 


Despite the crew’s efforts to recapture the runway centerline through use of rudder steering and differential braking, the aircraft departed the left side of the runway at high speed, approximately 1,263 feet from the departure end. The aircraft collided with the Runway 31 PAPI assembly, a high-strength metal boundary fence and trees. The three crewmembers asphyxiated in the ensuing fire.

 


Investigators also determined the accident pilots failed to arm the aircraft’s ground spoiler system while on approach to Le Castellet on a short repositioning flight from Nice-Côte d’Azur Airport. This caused the Eicas (engine indication and crew alerting system) to display the message gnd spoiler unarm throughout the landing sequence, but it apparently went unnoticed by the crew. Without the spoilers, the Gulfstream also briefly registered a loss of “on-ground” indications from the main-gear weight sensors, causing the thrust reversers to stow.

 


The BEA’s final report issued several recommendations aimed at improving operational procedures, including better training on how to recover from uncommanded nosewheel steering on the GIV. Investigators concluded that lack of training for the condition contributed to the crew’s improper response. Although it could not be determined if the left nosegear orientation cited in the report occurred without any crew input, or whether it was linked to stress on the nosewheel assembly, investigators noted that this accident was not the first in which uncommanded nosegear steering on the GIV was identified as a possibility.

 


Following a 2004 incident in Eagle, Colo., Gulfstream issued a “Maintenance and Operations Letter” to GIV operators about how to address sudden control issues with the nosewheel steering system, many of which are undetectable before touchdown. Several operators, Universal Jet Aviation among them, told investigators they were not aware of the letter, which was dated Dec. 14, 2004.

 


The BEA report also faulted the pilots for “inadequate preflight preparation” and for failing to use and follow the pre-landing checklist to detect the unarmed ground spoiler system. Investigators also noted that a standby emergency response firefighter was not present at the airport at the time of the crash, leaving the initial response to a single firefighter who was unable to douse the flames.

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