Alaska Airlines' all clear for grounded jets

MD-80s are under scrutiny following the crash

Alaska Airlines has cleared 17 of its Boeing MD-80 jets for a return to service one day after grounding them for fresh inspections following a crash off the California coast in January.

The airline earlier said a company-made tool used to check the jackscrew, which control the plane's stabiliser, may have produced incorrect readings.

Faulty jackscrews are suspected of causing the 31 January crash of Flight 261, which plunged into the ocean off southern California on a flight from Mexico to San Francisco killing 88 people.

The faulty jackscrew assembly is suspected of causing the crash

The crew had reported that the stabiliser had jammed.

Alaska officials said measurements on all 17 aircraft inspected on Friday were correct and did not show any additional wear and tear.

'Equivalent substitute'

The tool in question measures the amount of space between the thread on the jackscrew and the nut that holds it in place.

According to the MD-80 maintenance manual, airlines can measure jackscrew "endplay" using a tool made by the aircraft manufacturer or an equivalent substitute.

Alaska Airlines' Scott Patterson explains the problem with the company-made tool

However, the airline's tests, conducted in the course of the National Transportation Safety Board investigation into the crash, indicated that "endplay" measurement could vary if the company-made tool was improperly positioned.

"It is up to the US Attorney's Office to determine if this tool is a problem in their investigation," Mr Ayer said.

The company, which runs 500 flights a day, has 34 MD-80s airplanes in its fleet. Sixteen of them have been already checked with Boeing's tool to measure the stabiliser mechanics.

Disruption

In June, the Federal Aviation Authority announced that Alaska Airlines had made sufficient improvements to continue doing maintenance on its planes.

The US aviation authority alerted companies to check MD-80s and DC-9s

Previously, the agency had threatened to strip the airline of the right to carry out maintenance - a step that could have eventually grounded all its planes - unless its programmes were improved.

Investigations following January's crash included the discovery of nearly 150 cases in which scheduled heavy maintenance had been carried out but not documented and the use of maintenance procedures which had not been approved by the FAA.

Alaska Airlines then acknowledged that its record-keeping was less than perfect. However, the company said additional staff had been employed and the airline would do whatever it takes to continue to be a quality airline.