FAA to order inspections of older Boeing 737s
Southwest incident prompts directive, which covers 3 models
DALLAS – The Federal Aviation Administration today will order operators of older Boeing 737 airplanes to inspect them for cracks similar to the one that opened up a hole on a Southwest Airlines jet on Friday.
The FAA said Monday that the emergency directive will initially cover about 175 airplanes worldwide, including 80 in the United States – the majority flown by Southwest. It covers “high-cycle” aircraft, ones with more than 30,000 takeoffs and landings.
The order will cover three models from the so-called “classic” Boeing 737 generation – the Boeing 737-300s like the one that developed the gaping hole, the larger 737-400s and the smaller 737-500s. However, it does not cover all aircraft from those three models.
It will apply to “certain Boeing 737 in the -300, -400 and -500 series that have accumulated more than 30,000 flight cycles.” After the initial inspection, the directive will require “repetitive inspections at regular intervals,” the FAA said.
Dallas-based Southwest grounded 79 aircraft after one of its Boeing 737-300s developed a hole in its fuselage as the airplane was flying Friday afternoon from Phoenix to Sacramento, Calif. Pilots made an emergency descent and diverted the airplane to Yuma, Ariz.
The airplane’s fuselage lost a five-foot length on the roof, along a lap joint where one section of the fuselage’s skin overlaps an adjoining piece of skin.
The airline, the FAA and the National Transportation Safety Board have been inspecting the airplane. On Sunday, Southwest mechanics removed the portion of the fuselage around the missing section so it can be inspected further at NTSB offices in Washington, D.C.
Southwest said 64 of the 79 grounded aircraft had been inspected for cracks and returned to regular service. Three remained grounded after maintenance personnel found subsurface cracks on the aircraft, all built about the same time as the damaged airplane, which was delivered in mid-1996.
Southwest said its inspections done since Saturday should satisfy the FAA’s emergency directive. Its 25 Boeing 737-500s don’t come under the directive, it said.
After canceling 600 flights over the weekend, Southwest canceled about 70 flights Monday. Spokeswoman Brandy King said the airline hopes to get its schedule mostly back to normal today as it wraps up the remaining inspections.
Media representatives from Southwest told Spokane airport officials on Monday that none of its flights in or out of Spokane use Boeing 737-300 aircraft.
It’s not clear what might happen if the FAA requires Southwest and other airlines to extend mandatory inspections to other, newer versions of the Boeing 737, said airport spokesman Todd Woodard.
As of Dec. 31, Southwest operated 171 of the Boeing 737-300s, but it doesn’t plan to inspect aircraft beyond the 79 singled out after the Friday incident.
“We worked alongside Boeing to identify the 79 aircraft that required additional inspections,” King said.
“The remainder of the -300 fleet have undergone a lap joint modification – a skin replacement in a certain area of the airplane – which removed the requirement for certain required AD (airworthiness directive) inspections for skin fatigue,” she said.
King said the problem on Friday’s flight “was a new and unknown event. Prior to the depressurization event, there was not an inspection protocol for this area of the aircraft where the rupture occurred.”
The incident isn’t likely unique to Southwest, according to analysts. But the carrier reaches lifetime-cycle rates for its aircraft more quickly than its peers because of its high number of short-haul hops between regional airports.
Where other airlines may fly their jets two or three times a day for longer periods of time, Southwest flies its jets nearly seven times a day, on average.
That equates to 14 takeoffs and landings, which is when an aircraft comes under the most stress as the fuselage is pressurized and depressurized, expanding and contracting the plane’s skin and joints.
So far, other airlines have not grounded any of their 737-300s.
Friday’s incident raises concern that the 737 aircraft is not being inspected enough by operators, said Teal Group analyst Richard Aboulafia, noting that the lifetime of the popular single-aisle jetliner should be 25 to 30 years.
“At the end of the day, there’s no reason why a plane like the 737 should suffer any structural problems if they are properly inspected,” Aboulafia said. “Given the number of cycles, are the number of inspections adequate?”