NASA gathered the information under an $8.5 million safety project, through telephone interviews with roughly 24,000 commercial and general aviation pilots over nearly four years. Since ending the interviews at the beginning of 2005 and shutting down the project completely more than one year ago, the space agency has refused to divulge the results publicly.
Just last week, NASA ordered the contractor that conducted the survey to purge all related data from its computers.
The Associated Press learned about the NASA results from one person familiar with the survey who spoke on condition of anonymity because this person was not authorized to discuss them.
The AP sought to obtain the survey data over 14 months under the U.S. Freedom of Information Act.
"Release of the requested data, which are sensitive and safety-related, could materially affect the public confidence in, and the commercial welfare of, the air carriers and general aviation companies whose pilots participated in the survey," Luedtke wrote in a final denial letter to the AP. NASA also cited pilot confidentiality as a reason, although no airlines were identified in the survey, nor were the identities of pilots, all of whom were promised anonymity.
The survey also revealed higher-than-expected numbers of pilots who experienced "in-close approach changes" _ potentially dangerous, last-minute instructions to alter landing plans.
Officials at the NASA Ames Research Center in California have said they want to publish their own report on the project by year's end.
"If the airlines aren't safe I want to know about it," said Rep. Brad Miller, R-N.C., chairman of the House Science and Technology investigations and oversight subcommittee. "I would rather not feel a false sense of security because they don't tell us."
Discussing NASA's decision not to release the survey data, the congressman said: "There is a faint odor about it all."
Miller asked NASA last week to provide his oversight committee with information on the survey and the decision to withhold data.