NASA astronauts have flown jets dangerously close to other airplanes at least three times since May 1989, the National Transportation Safety Board (NTSB) said Tuesday. The NTSB, in a report to NASA administrator Richard Truly, said NASA's jet fleet has aged and has substandard communications equipment and the agency should correct problems "before other dangerous situations are created."
The board said the three near-collisions were among seven incidents since 1986 in which astronauts flew jets below assigned altitudes.
In the closest encounter, veteran Navy Capt. David M. Walker on May 15, 1989, flew his T38 jet within 100 feet vertically and 700 feet horizontally of a Pan Am jetliner with 176 people on board.
The Walker incident happened near Dulles International Airport as the shuttle commander arrived in the Washington area to be congratulated the next day by President Bush for completing a successful mission, Walker's second.
The Pan Am crew "could make out the tail number on the airplane," Tim Borson, an NTSB investigator told the board members at a hearing Tuesday.
None of the NASA pilots was identified in the NTSB report to Truly. Walker's involvement was known at the time. He was suspended in July along with Navy Cmdr. Robert L. Gibson, who was being disciplined in an unrelated matter. Walker was also replaced as commander of a space shuttle mission scheduled for next year.
Borson said during the third quarter of 1990 alone, astronauts flew NASA's 28 T38s an average of 843 times a month and that the planes were used for 697 cross-country flights. The T38 is a high performance jet capable of flying at 1.6 times the speed of sound.
The safety board was critical of the T38s and said NASA's communications equipment was "outdated and far from state-of-the-art."
It recommended astronauts fly with an additional crew member when landing or taking off in busy airports and urged that NASA instruct its pilots to write down flight controllers' instructions.
All three incidents discussed at the NTSB meeting could have been averted if a second crew member had been flying in the T38, the NTSB said.
The board also recommended that the equipment on board the jets be modernized to include more safety features.
The changes are needed, NTSB said in a letter to Truly, "to reduce the potential for human error."
Truly called the NTSB report "thorough and constructive" and said NASA would consider all of the recommendations.