By Steve Miletich

Seattle Times staff reporter

Federal safety investigators have concluded that risky maintenance practices permitted by the Federal Aviation Administration, combined with a design flaw in a key airplane mechanism, led to the fatal crash of Alaska Airlines Flight 261 in January 2000.

In a draft report nearing its final stages, the staff of the National Transportation Safety Board says "insufficient lubrication" led to the failure of the jet's jackscrew mechanism, a key component in the plane's tail. It portrays Alaska as an airline that operated on a thin margin of error, with serious flaws in its maintenance operations.

But the report also faults the design of the plane, an MD-80 built by McDonnell Douglas before its 1997 merger with Boeing. That represents a setback for Boeing, which has argued that the crash wouldn't have occurred if the jackscrew mechanism had been properly maintained.

Flight 261: Key recommendations

A draft report by the staff of the National Transportation Safety Board

recommends:

Design changes to Boeing MD-80 series and 717 jets to prevent the kind of catastrophic failure that led to the Flight 261 crash.

More direct Federal Aviation Administration oversight of airlines' maintenance practices; less reliance on airlines to govern themselves.

Another top-to-bottom inspection of Alaska Airlines' maintenance operations to ensure that changes promised in the wake of Flight 261 have been carried out.

If upheld by the safety board and the FAA, the finding could lead to an order for modifications to MD-80-series planes as well as the 717, a cousin of the MD-80 that is still built by Boeing at a former McDonnell-Douglas plant in California. More than 1,400 jets could be affected.

The report will be submitted to the safety board's four appointed members before a public hearing tentatively set for Dec. 10 in Washington, D.C. Key portions of the draft were read to The Seattle Times by an official close to the investigation.

Alaska, Boeing and the FAA declined to comment pending the release of the findings.

Ted Lopatkiewicz, chief spokesman for the safety board, said yesterday that board members had not seen the draft report and could make "substantial revisions" in it.

Flight 261 crashed Jan. 31, 2000, off Southern California, killing all 88 passengers and crewmembers as the plane was en route from Puerto Vallarta, Mexico, to San Francisco and Seattle.

The report, as expected, concludes that the probable cause of the crash was failure of the jackscrew mechanism, which sent the MD-83 into a dive into the Pacific.

The jackscrew is a 2-foot-long, 1-1/2-inch-diameter threaded shaft that moves up and down, raising and lowering the leading edge of the stabilizer, the winglike structure on the tail that controls the plane's angle of flight.

The report says a lack of grease in critical areas of the jackscrew assembly caused excessive wear, stripping threads from the mechanism's stationary gimbal nut. The jackscrew moved beyond its limits, causing the stabilizer to fail.

While the report doesn't pinpoint the reason for the lack of grease, it states that Alaska, with the FAA's approval, reduced the frequency with which it lubricated the mechanism, increasing the likelihood of excessive wear.

Alaska, also with the FAA's assent, increased the inspection time to detect wear on the mechanism, the report says.

Since the crash, Alaska has completely revamped its procedures under pressure from the FAA. The FAA, itself under scrutiny, has bolstered its oversight of the carrier.

For Boeing, the most significant part of the report is its conclusion that the MD-80's design is faulty because it doesn't account for the "catastrophic effects" of complete thread loss on the jackscrew mechanism.

Without a required backup system, the pilots had no way to regain control of the plane when the jackscrew mechanism failed.

The MD-80 series was manufactured beginning in 1980 by McDonnell Douglas and discontinued by Boeing in 2000. It is based on the Douglas DC-9, which dates to the mid-1960s.

In addition to the findings regarding the cause of the crash, the safety-board report recommends that the FAA:

* Take more control over changes to maintenance intervals, instead of leaving the decision in the hands of airlines' internal-review boards.

* Order airlines to follow stricter protocols for lubricating aircraft components, including requiring that airline safety inspectors personally sign task cards to assure that lubrications have been done properly. The board's staff, after discussion, decided not to require that jackscrews be automatically replaced at regular intervals instead of when they wear out. But it did recommend the FAA establish training requirements specifically for mechanics who inspect and overhaul jackscrew mechanisms.

* Require Boeing to modify MD-80-series planes still in use, as well as 717s, to add backup systems. Boeing has indicated to the board that it could make two or three such changes. About 1,190 MD-80s, 115 MD-90s and 106 717s could be affected. The cost has not been determined.

* Issue a bulletin to pilots instructing them not to try to fix jackscrew problems in flight, but to land at the nearest airport. The two pilots aboard Flight 261 fought problems for at least 30 minutes before the crash.

* Conduct another major inspection of Alaska's maintenance operations, as it did in April 2000, to make sure the carrier has fully adopted changes stemming from that review.

Some board investigators still have concerns about the airline's practices, a senior official said.

The April 2000 inspection prompted the FAA to threaten to shut down Alaska's major-repair facilities. The airline averted the action by making sweeping changes in its maintenance program, including the hiring of hundreds of mechanics.

The new inspection should go beyond a review of paperwork and include visual inspections of Alaska's procedures, the report says.

The jackscrew that failed during Flight 261 had been found to be at its maximum allowable wear limit during a September 1997 test, but flew for 25 months without another inspection before the crash.

Even though a senior Alaska mechanic called for replacement of the component after the 1997 test, other mechanics re-checked it, found it to be well within limits and decided not to replace it as the plane was nearing its release date.

Safety-board investigators have found that some Alaska maintenance logs that were supposed to be kept at the time of those tests are missing, said the official close to the investigation.

The report's finding regarding insufficient lubrication followed a fierce internal debate among the safety board's staff about whether to allege the jackscrew assembly had not been greased at all, the official said.

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But because task cards were filled out stating lubrications had occurred, there was no way to prove they weren't done, the official said. Alaska has asserted that a jammed fitting possibly obscured a lack of grease.

Just in the past two months, Alaska sharply increased how often it lubricates all components in its MD-80-series jetliners when problems were found.

The safety board's findings will be closely reviewed by lawyers representing dozens of families with wrongful-death suits against Alaska and Boeing, as well as attorneys defending the companies.

A federal trial that could cost the companies millions of dollars in damages is set to begin in April in San Francisco. Boeing is liable for potentially huge punitive damages; Alaska is not because of an international aviation treaty protecting carriers.

"The findings of the NTSB have been long-awaited by the families," said Jamie Lebovitz, a Cleveland attorney representing 18 families, "and will certainly be of value in the civil proceedings."

Lebovitz said the plaintiffs have gathered evidence showing McDonnell Douglas knew years ago that jackscrew mechanisms were vulnerable to wear, but never instructed pilots how to deal with a jammed stabilizer.

On Flight 261, the "pilots were turned into test pilots," he said.

Steve Miletich: 206-464-3302 or smiletich@seattletimes.com.

Anarudh V. Prasad