A former air accident investigator campaigning for a new probe into the 1996 crash of TWA Flight 800 said Monday that US authorities appear to be taking his request seriously.

The National Transportation Safety Board (NTSB) maintains that a fuel tank explosion, possibly ignited by faulty wiring, brought down the Paris-bound Boeing 747 soon after takeoff from New York, killing all 230 people on board.

A 90-minute documentary, "TWA 800," which premieres on the Epix cable channel on Wednesday, the 17th anniversary of the disaster, argues that the jumbo jet was downed by missiles and alleges a high-level cover-up.

At a screening Monday in Washington, former NTSB investigator Hank Hughes, a central figure in the film, said the petition he filed on June 19 for the case to be reopened is making headway.

"My understanding is that they are in the process of selecting the individuals" who will review the petition, he told AFP, referring to the NTSB, a federal government agency.

"Hopefully they won't be people who were involved in the original investigation, so they can take a clean look at it... I think, from what I have been hearing, that they are taking it seriously."

The NTSB, which spent four years investigating the disaster, must respond to Hughes' petition within a 90-day period that would end September 17.

Virtually forgotten since the 9/11 attacks in 2001, the loss of TWA 800 was first thought to have been an act of terror, before the focus of the investigation veered toward the fuel tank beneath the passenger cabin.

Empty of fuel, the garage-sized tank was nevertheless filled with explosive vapor that the NTSB concluded was "most likely" ignited by a short circuit relating to the electrical fuel gauge sensors.

"I'm totally convinced there was no bomb or missile," retired NTSB investigator Jim Wildey, who oversaw a detailed analysis of the sequence of events surrounding the disaster, told a NTSB media briefing on July 3.

"TWA 800" cites radar data from the instant of the disaster as the "smoking gun" that suggests the flight might have been the victim of surface-launched proximity fuse missiles.

Such weapons are designed to go off within a few yards (meters) of a target, without actually hitting it, said physicist Tom Stalcup, the film's co-producer, who has spent years delving into the disaster.

The film also quotes some of the hundreds of witnesses interviewed by FBI agents, but never summoned before the NTSB, who say they saw what appeared to be a missile soaring into the evening sky, followed by an explosion.

"It looked like a flare going up," one witness says in the film, while another described a streak of light "going straight up."

The NTSB's view is that the Boeing 747 broke in half upon exploding. What people on the ground saw was the rear part, with wings intact, ascending briefly in flames before plunging nearly 15,000 feet (5,000 meters) into the sea.

Stalcup, who in his film names then-president Bill Clinton among those who declined to be interviewed, refrained from speculating about who might have downed Flight 800, and no group as ever claimed responsibility.

But at Monday's screening he said "not one fact" in the petition to reopen the investigation has so far been challenged, and that the NTSB "hasn't addressed the evidence" set out in his film.

The remains of TWA Flight 800 were largely recovered from the waters off Long Island. Most of the fuselage is now reassembled at the NTSB academy outside Washington, where it is used to train accident investigators.

Besides Hughes, who oversaw the hanger on Long Island where the wreckage was first gathered, "TWA Flight 800" features two others closely involved in the case -- Bob Young, chief accident investigator for now-defunct TWA, and James Speer, who held down a similar position at the Air Line Pilot Association.