SEATTLE -- Alaska Airlines has completed 12 of an expected 17 inspections of MD-80 aircraft, one day after announcing that a tool used to measure stresses on the jets' tail sections may have given the wrong readings.
Alaska said the tool in question, made by the airline itself, could give incorrect measurements of stresses on the jackscrews in the MD-80s' horizontal stabilizers. The same part has been implicated in the Jan. 31 crash of Alaska Flight 261 off the California coast, which killed all 88 people aboard.
Alaska spokesman Jack Evans said Friday that of the 12 aircraft inspected overnight, the stress measurements were correct and did not show any additional wear and tear. The company was expected to inspect five more MD-80s later in the day.
Originally, the company said 18 jets would be grounded for the inspections, but Evans said one of those was found to have been inspected with a different tool -- made by plane manufacturer McDonnell Douglas -- and was released back into service.
Airline officials told the Federal Aviation Administration on Thursday that its tool used to check jackscrews may have produced incorrect readings. The assembly consists of a nut that rides up and down a screw as it is turned to raise and lower the stabilizer, a wing-like part of the tail that is used to raise or lower the nose of the plane in flight.
There are no indications of problems, but other airlines also have been told to check MD-80 and DC-9 planes, according to an FAA statement.
The scramble resulted in cancellation of 18 Alaska Airlines flights late Thursday, including eight from the company's principal hub at Seattle-Tacoma International Airport. Another 29 flights would be canceled Friday, far below the 72 flights the company had estimated Thursday night, Evans told The Associated Press.
Neither Evans nor other Alaska Airlines spokesmen returned calls to the Juneau Empire on Friday morning, so the effect of the inspections on Juneau passengers is not clear.
Juneau Airport Manager Allan Hesse said the airline does not normally fly MD-80s in and out of Juneau. He had not heard whether any Juneau flights had been canceled or delayed due to the groundings.
Alaska, the dominant carrier on north-south routes along the West Coast, normally operates about 500 flights a day with a fleet of 90 planes, including 34 MD-80s. The company was providing meal vouchers, rebooking some passengers and offering others hotel rooms overnight.
``Whatever we need to do for them, we're trying to do for them,'' Evans said.
Kip Leach, an oil production operator in Alaska, was given dinner, breakfast and hotel vouchers after his connecting flight to Phoenix was canceled Thursday night. He told The Seattle Times he also would demand a free flight in the future.
``Me and Alaska's consumer affairs will be talking,'' Leach said.
Michael Abrams, at Sea-Tac on Friday morning to pick up a friend who'd been scheduled to arrive Thursday evening, said he plans to write a letter to Alaska, complaining about the carrier's refusal to book his friend on another airline.
``Airline officials said that was not Alaska's policy,'' said Abrams, 42, a Seattle engineer. ``And it's very frustrating.''
But most flights were on schedule.
The Boeing Co. took over production of the MD-80, which is based on the DC-9 airframe, after absorbing McDonnell Douglas in a $16.3 billion merger in 1997. Out of about 2,000 MD-80-series and DC-9 jetliners worldwide, more than 1,100 are flown by U.S. carriers.
In the wake of the Alaska Flight 261 crash, the FAA conducted a ``white-glove'' inspection of the airline's maintenance facilities and found more than 150 instances of improper or missing paperwork. The probe found that maintenance had been done correctly, however.
In June, the FAA announced that Alaska Airlines had made sufficient improvements to continue doing its own airplane maintenance. Previously, the agency had threatened to strip the airline of the right to do maintenance, which could have eventually grounded all its planes.
A criminal investigation into the crash has focused on a mechanic's decision not to replace a jackscrew assembly. The jackscrew had been tested repeatedly and found to be nearly worn out but was returned to service after a second crew retested it a few days later. Two Alaska Airlines mechanics from that second crew insisted in an interview with the Times that they were not at fault.
The tool in question measures the amount of space between the thread on the jackscrew and the nut that holds it in place.
Airline tests, part of the National Transportation Safety Board's crash investigation, indicated jackscrew ``endplay'' measurement could vary. According to the MD-80 maintenance manual, airlines can measure endplay with a tool made by the aircraft manufacturer or an equivalent substitute.
Alaska owns tools made by the manufacturer but also uses several that were made in its own machine shop.
In side-by-side tests, the tools produced the same results, ``but we found that the results could vary if the Alaska-made tool is incorrectly positioned,'' said Bill Ayer, Alaska's president and chief operating officer.
``We know that the tool used on Flight 261 was a tool we manufactured,'' he said. ``It is up to the U.S. Attorney's Office and the NTSB to determine if this tool is a problem in their investigation.''
National Transportation Safety Board spokesman Paul Schlamm confirmed Friday that questions about Alaska's measurement tools would be included in its investigation of Flight 261.
Once Alaska officials verified that the manufacturer's tool was used to measure the jackscrews on 16 of its 34 MD-80s, the decision was made to reinspect the remaining 18.
Ayer said airlines often make their own maintenance tools and declared the MD-80s safe.
``There's no more inspected airplane in the world than the MD-80, especially the Alaska MD-80s.'' he said.