The company's shares fell around 3.22 per cent to 261.5p after it said current chief financial officer, Simon Nicholls, is leaving to take up the same role at plumbing supplies group Wolseley.
Nicholls, who will stay in his current role until a successor has been identified, is expected to leave Cobham towards the end of this year. The search for a replacement is already underway.
"This move places Simon among the top 40 FTSE financial leaders and offers an exciting opportunity for him to further his career," Cobham said in a statement to the London Stock Exchange.
"We thank Simon for the leadership contribution he has made at Cobham over the past three years and although we'll miss him, we are also very pleased, wishing him every success in his new role."
In November, market headwinds and delayed orders in its US business forced Cobham to warn full year profits would be at the lower end of forecasts.