America's air safety regulator has ordered what's known as an "airworthiness directive" for all 737 planes that fly in U.S. airspace to replace tail plane fixing pins that can corrode and become defective. The concern stems from how the tail plane fixing pins were coated with a protective surface. The horizontal stabilizers govern up-and-down movement in the plane's nose.
"We are issuing this AD to prevent premature failure of the attach pins, which could cause reduced structural integrity of the horizontal stabilizer to fuselage attachment, resulting in loss of control of the airplane," the FAA said in a release.
The order was "prompted by reports of an incorrect procedure used to apply the wear and corrosion protective surface coating to attach pins of the horizontal stabilizer rear spar."
The order does not ground the plane, but asks airlines to inspect and change their 737s as needed with the affected part by May 20.
The total cost of replacement parts is expected to be just over $10 million across the entire fleet, which suggests a cost of roughly $9,600 per aircraft.
The order encompasses 1,050 U.S.-domiciled planes, but planes that fly into U.S. airspace would also be included. According to Transport Canada, there are 176 Boeing 737s registered to fly in Canada, tha largest number of which are owned by Calgary-based WestJet.
Asked for comment on the FAA order, a spokesman for Calgary-based WestJet told CBC News the company was still "digging into" the issue, and had yet to "find out if it applies."
Through direct flights and code-sharing agreements with other airlines, WestJet flies to dozens of U.S. destinations.