Southwest Halts More Flights

Southwest Airlines Co. canceled more than 60 flights Monday as safety personnel continued inspections for fuselage cracks in its fleet of Boeing 737-300 jetliners, days after one of the planes sustained a ruptured hull while in flight.

Shares of Southwest /quotes/comstock/13*!luv/quotes/nls/luv (LUV 12.35, -0.32, -2.53%) fell 3% to $12.31 in early trading. For the year to date, the stock is down about 7.6%, versus a 5% climb in the benchmark Standard & Poor’s 500 Index /quotes/comstock/21z!i1:in\x (SPX 1,334, +1.42, +0.11%).

Altogether the Dallas-based carrier is expected to cancel some 100 flights on Monday, according to a late Sunday news release, following the grounding of about 300 flights over the weekend. FlightAware, a travel service Web site, showed Southwest had canceled 64 flights as of early Monday.

Cracks have been found in at least three 737-300 jets since safety checks began, according to the National Transportation Safety Board, which is supervising the inspections. Boeing Co. /quotes/comstock/13*!ba/quotes/nls/ba (BA 73.93, -0.08, -0.11%) manufactured the 737-300s.

Of 79 of the jets pulled for inspection, more than 30 have been returned to service, said Southwest spokesperson Whitney Eichinger. Inspections should be completed by Tuesday afternoon.

On Friday, a Southwest flight made an emergency landing after the 737-300 fuselage ruptured 36,000 feet above Arizona, ripping open a yard-long hole. The plane landed safely with only minor injuries reported.

The damaged fuselage skin from that plane was sent to the Safety Board headquarters in Washington, D.C., for in-depth analysis.

“Boeing has since identified an inspection program for this section of the aircraft,” said Mike Van de Ven, Southwest’s chief operating officer, in a Sunday statement. “Based on this incident and the additional findings, we expect further action from Boeing and the [Federal Aviation Administration] for operators of the 737-300 fleet worldwide.”

Southwest owns one of the largest 737-300 fleets flying, along with International Lease Finance Corp., Ireland’s GPA Group, and United Airlines, now a part of United Continental Holdings Inc. /quotes/comstock/13*!ual/quotes/nls/ual (UAL 22.59, -0.35, -1.53%)

Chicago-based Boeing is expected to soon draft a service bulletin, based on the analysis to date, to describe inspection techniques recommended for similar airplanes that are flown nearly as frequently, the NTSB said.

Southwest aircraft have one of the highest utilization rates in the industry, with short turnaround times at airport gates. It’s fleet of 737-300 jets were delivered to the company form 1984 through 1997.

This is at least the second time Southwest has had to contend with fuselage cracks. In July, 2009, the airline inspected all its 737-300 jets after a one-foot hole opened up at the top of its fuselage in mid-flight.

The FAA later called for stepped-up inspections of Boeing 737 planes for undetected cracks that “could result in sudden fracture and failure of the fuselage skin panels, and consequent rapid decompression.”

Southwest, which operates 181 Boeing 737-300 jets, said Friday’s incident was not related to the one in 2009. No one from NTSB was immediately available to comment.

The FAA said it wasn’t yet known whether the incidents were related, but a recent NTSB report on the incident focused on the so-called chem-milled lines of the fuselage skin, which are used to help make the skin lighter. For the Friday incident, the NTSB is focusing on the “left- and right-lap joints.”

“The issue in 2009 was in a different location and affected a different portion of the aircraft,” said Southwest’s Eichinger.