The US Federal Aviation Administration (FAA) will order operators to replace and change the routing of an oxygen hose in the cockpits of hundreds of Bombardier CRJ100 and CRJ440 regional jets.
An airworthiness directive will be published in the Federal Register on 28 June that mandates the changes on 588 aircraft in the US registry.
The FAA estimates the costs of the changes will be about $1,210 per product, including $108 for parts and 13h of labour.
The airworthiness directive was ordered after a ground fire was reported in the Bombardier aircraft. The fire was fed by oxygen escaping from a damaged oxygen line supporting a third crewmember sitting in the jump seat, the FAA says.
To avoid similar incidents, the directive will require the operators to replace the flexible oxygen hose and re-route the hose so it cannot be damaged.
The changes must be made within 4,000 flight hours after the effective date of the directive, which comes 35 days after it is published in the Federal Register.
The FAA rejected a request by the Air Line Pilots Association to force operators to make the compliance window shorter than 4,000 flight hours. Canada's airworthiness authority has already issued an identical airworthiness directive.