Jetliner in Azores Crash Had Instrument Problems in 1987

The Boeing 707 jetliner that slammed into a mountainside Wednesday in the Azores after apparently straying off course was forced in July, 1987, to make an unscheduled landing in Atlanta when its altimeter and airspeed indicators gave off erroneous readings, federal records show.

Since 1980, the aircraft has had 13 incidents that were serious enough to merit reporting to the Federal Aviation Administration by its owner and operator, Independent Air Corp. of Smyrna, Tenn.

The records also show incidents of cracks, corrosion and a series of problems with landing gears. In theory, the service difficulty report system was set up to call attention to problems that are not supposed to occur on aircraft, but in practice, some of the problems are not that rare.

A. L. Pittman, president of Independent Air Corp., said the 707 did not have a history of mechanical or structural problems. He added that he had no information about the incident involving the altimeter and airspeed indicator, but he assumed that the problem was fixed.

“I don’t recall that, but I bet it was fixed,” he said.

Altimeters, which provide a pilot with the altitude of the aircraft, operate by measuring air pressure, which drops as altitude increases. Accurate readings are important, especially when flying around mountainous areas.

The incident was described in a computerized data base of service difficulty reports, which The Times obtained from the FAA. Independent Air filed the report with the FAA.

Pittman said the aircraft was in good condition and in December had passed a major structural integrity inspection, known in the industry as a “D” check.

Boeing said the 707 jetliner was delivered in March, 1968, to TWA, the original owner. Neither Boeing nor Pittman could say when the aircraft was sold by TWA or whether there were other owners before Independent Air acquired it.

The four-engine 707s, which first began passenger service in 1962, are now widely considered out of date and uneconomical. They are no long used by any scheduled airlines in the United States, but 450 of the aircraft are still in use by foreign airlines and charter operators.

Boeing has produced 891 of the aircraft and still builds limited numbers of them for the military, which uses them for airborne communications and radar posts. Independent Air’s 707 was the 687th 707 built by Boeing.

The 20-year old aircraft, one of two 707s owned by the company, had made 12,500 sets of takeoffs and landings and logged 45,000 hours in the air, Pittman said in a telephone interview. Boeing and FAA officials said that those figures are not unusually high for an aircraft that age.