By Conor Shine
The Dallas Morning News
DALLAS — The Federal Aviation Administration is calling for more frequent, ongoing inspections of tens of thousands of engine fan blades in airline fleets across the U.S. to check for “unsafe conditions” in the wake of the fatal April 17 Southwest accident.
The agency cited the “risk to the flying public” in calling for more frequent inspections on 3,716 CFM56-7B engines installed on U.S. airplanes — each engine has 24 fan blades.
The latest regulatory move comes about 20 months after a similar mid-air engine failure forced another emergency landing.
The agency released an updated airworthiness directive, scheduled to be published Wednesday, that supplements an emergency order put out days after the accident, when a fan blade broke off a Southwest engine aircraft, sending debris into the plane and causing a window to blow out. A passenger sitting next to the window later died from her injuries.
The National Transportation Safety Board said in the hours after the accident that the broken fan blade showed signs of interior cracking, known as metal fatigue. A similar incident occurred in 2016 when a fan blade broke off an engine on a Southwest flight from New Orleans to Orlando.
“This (airworthiness directive) addresses the unsafe condition affecting CFM56-7B engines by requiring initial and repetitive inspections of fan blades based on accumulated fan blade cycles,” the directive said. “This condition, if not addressed, could result in fan blade failure due to cracking, which could lead to in an engine in-flight shutdown, uncontained release of debris, damage to the airplane, and possible airplane decompression.”
The CFM56-7B engine involved in the accident is one of the most common types used to power 6,700 aircraft worldwide. It’s manufactured by CFM International, a joint company of General Electric and France’s Safran Aircraft Engines.
The FAA’s emergency directive issued April 20 called for ultrasonic inspections of fan blades in engines with more than 30,000 takeoffs and landings within 20 days. The updated advisory is expected to go into effect at or near the end of that 20 day-window, the FAA said.
It will add new requirements for the initial inspection of engines not affected by the emergency directive and recurring inspections for all engines.
The new directive requires all engine fan blades to be inspected when they have undergone 20,000 takeoff and landing cycles, or by Aug. 31 if already past that threshold. Inspections will then be repeated after every 3,000 cycles, typically 1.5 to 2 years of service, according to CFM International.
Southwest said last Thursday it had inspected about 25,000 of the 35,000 fan blades in its fleet. Of those inspections, only one fan blade in 2017 showed signs of cracking and was replaced, the company said.
Southwest’s current maintenance program already calls for the fan blades to be inspected every 3,000 cycles, a change put into place late last year in response to the 2016 incident, CEO Gary Kelly said last week. The fan blade that broke off during Flight 1380 was scheduled to be inspected by the end of 2018, but hadn’t been recently checked prior to the accident because of the engine’s age.
Online tracking portal FlightAware logs show that the plane involved in the April 17 accident was flown Monday from Philadelphia to Everett, Wash., where Boeing has one of its largest aircraft manufacturing facilities.
The directive came the same day President Donald Trump met with the Flight 1380 flight crew and several passengers at the White House.
