KEY POINTS:
Experts now doubt that the fiery fragments that narrowly missed an Auckland-bound aircraft were the remains of a Russian satellite.
The fragments thundered past the Lan Chile Airbus 340, which was carrying up to 300 people from Santiago, Chile, about 10pm on Tuesday.
The pilot reportedly saw the objects and heard a boom as they entered the atmosphere, about 10km in front of and behind the aircraft.
Captain Steven Anderson, assistant secretary of the Australian and International Pilots Association, said the objects must have been very large to be heard.
"To hear it over the noise of the aircraft [it] would have to be exceptionally loud. If it was a sonic boom and a large piece of debris, if that had hit the aeroplane it would have been quite catastrophic."
The aircraft completed its flight without incident and Lan Chile reported what had happened to aviation authorities in New Zealand and Chile.
Captain Anderson said it was unlikely the object was a satellite as most space debris burned up by the time it reached cruising altitude of about 35,000 feet (10,668m).
"I would imagine that a satellite, by the time it reached the aircraft, would have been completely destroyed," said Captain Anderson, who has 27 years' international flying experience.
The chance of colliding with a meteorite in mid-flight was practically zero, he said.
The pilot's initial reports were that he saw a man-made object. Space agencies are required to track space debris and publish when and where it might re-enter the atmosphere.
The process has been described as reliable, prompting speculation that the fragments were from a meteorite.
Debris from a Russian satellite was scheduled to re-enter the atmosphere about 12 hours after the near-miss, and the US space agency, Nasa, said yesterday that the debris came through at the expected time.
Questions also remain over where the incident occurred. It was initially reported that it happened just after the Auckland-bound aircraft entered New Zealand airspace.
But Lan Chile said yesterday the flaming object was seen a few minutes before reaching New Zealand airspace.
"The captain reported to have had visual contact with incandescent fragments several kilometres from the aircraft. The aircraft landed safely at Auckland Airport and continued flying to Australia as scheduled," the airline said.
Lan Chile would not comment on the number of people on board, but it is understood there were 250 to 300 passengers and crew - nearly a full load.
Authorities and pilots the Herald spoke to said they had not heard of any occasion when a pilot had seen and heard debris passing by an aircraft.
Civil Aviation Authority spokesman Bill Sommer said dumping space junk took place on a fairly regular basis, though it was not frequent.
"Space agencies track satellites, and if they're coming down they can predict when and where reasonably accurately. Airlines will then have that information and make sure they don't fly through those areas.
"It's a large chunk of ocean where there's no people, no islands in the area, and it's used to bring satellites back down and put them into the sea."
The system was reliable and "if I was a betting person, I would bet on a meteorite rather than space debris".
Airways New Zealand, which manages air traffic in New Zealand's airspace, has not ruled out the possibility of a meteorite, spokesman Ken Mitchell said, even though "the pilot's initial assessment was that he was encountering space debris of a man-made nature".
The Civil Aviation Authority investigation is expected to be complete within a month.
