The Federal Aviation Administration immediately grounded 179 old Boeing 737s for inspections Sunday after finding damage to fuel-pump wiring in some planes, issuing a rare order that disrupted travel at some of the nation’s airports.
The agency also ordered the inspection of some middle-aged Boeing 737s but gave airlines two weeks to complete the reviews without grounding those planes.
The agency grounded the older models after discovering that a majority of 13 planes inspected since Thursday, when the FAA first identified the problem, had some worn wire insulation. Blaming engine vibration as the probable culprit, agency officials said they feared that frayed insulation could lead to a spark from the 110-volt wires that could cause a fire or explosion.
With planes grounded in some places that had no mechanics or equipment to complete the inspections Sunday, up to 100,000 passengers a day across the country could find their flights canceled or delayed this week, a top agency official predicted. The official, Thomas McSweeny, predicted that the disruption might last for days because of a shortage of parts to make repairs.
However, at O’Hare International and Midway airports, problems were minimal.
United Airlines officials said they did not know how many flights had been canceled or delayed at O’Hare. But, by Sunday afternoon, of the 152 flights scheduled to depart, only six had been canceled and four had been postponed.
“A snowstorm at O’Hare would cause problems that are three or four times worse than what we are experiencing today,” said United spokeswoman Mary Jo Holland.
Holland said the FAA’s initial directive targeted 31 of United’s 600 planes. By Sunday, 18 of those planes still had not been inspected.
“We’re going to spend the rest of the day and night inspecting these planes and, if all goes well, they will be ready to go tomorrow,” said Joe Hopkins, a United spokesman based in Chicago.
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United ticket agents quickly placated passengers with rebookings and a coupon good for a free round-trip anywhere in the United States.
Heather Conely, who was booked on a 3:25 p.m. flight home to Minneapolis after visiting her parents in Chicago, said, “I really can’t complain with the deal I’ve got.”
Her mother and father were coming out to O’Hare for dinner, she said, and United had booked her on a 9 p.m. flight.
Miriam Bonkowski had come to Chicago to visit her daughter and a new grandchild and was booked on the same flight to Minneapolis. “It’s an inconvenience, sure, but you expect this kind of thing, especially during holiday travel,” she said, referring to Mother’s Day.
A spokeswoman with Southwest Airlines–the main server at Midway–said the company accelerated its inspection program last week in anticipation of Sunday’s announcement. Of the 35 Southwest aircraft covered by the grounding, only two had not been inspected by Sunday. Those two will be inspected by Monday morning.
“We had no delays and no cancellations due to this issue,” said Melanie Jones, a Southwest spokeswoman.
Other airports, including Atlanta and New York’s LaGuardia, reported some delays.
“While we are concerned about that and the disruption it has in the system, the No. 1 priority we have is safety,” McSweeny said. Until now, the wiring and insulation for the fuel pumps was expected to last the lifetime of a plane and did not require any sort of regular inspection. But the potential hazard is prompting federal aviation officials to consider mandating regular reviews of fuel-pump wiring.
The grounding order covers about 15 percent of the 737s in use in the U.S., those that have logged 50,000 hours of use and are at least 20 years old. The other inspection order issued Sunday affects 737 models with 40,000 to 50,000 hours of use.
The 737 is the world’s most popular jetliner. According to Boeing, 2,975 have been delivered, with most of them still flying, and more than 900 more have been ordered.
Boeing said it supported the FAA’s decision and was sending out repair kits as quickly as possible.
The agency’s decision to ground the jets is the first such order since the FAA acted against McDonnell Douglas DC-10s in 1979, after a crash in Chicago. This time, however, the order is precautionary, following the discovery by mechanics at Continental Airlines late last month that fuel was leaking into a wiring conduit in the wing tank of one of their 737s.
Since the explosion of a TWA Boeing 747 nearly two years ago off the coast of Long Island, the FAA and the National Transportation Safety Board have been studying the possibility that a fire in a wing tank could have spread through a vent line to the wing tank and then back to the center fuel tank. There is no hard evidence, they caution, to prove this scenario, although faulty wiring has long been mentioned as one of the most likely causes of the 747 explosion.
In the case of the Continental jet last week, Boeing engineers, working with FAA inspectors, determined that the leaking fuel came through small holes in the conduit, holes that were burned into the aluminum by sparks from the wires.
After first learning of the mechanical problem Thursday, the FAA allowed the planes to continue flying but ordered airlines to inspect them within seven days.
But Saturday, mechanics at United Airlines, complying with the order, found a wire on an old 737 that had been rubbed raw in at least three areas, with signs of sparking in at least one area. In addition, most of the other planes that had been inspected by Saturday morning had wires that showed some signs of fraying, officials said, prompting the grounding order.