Research on deadly collision at the end of January in Washington between a plane and a American army helicopter highlighted several tens of meters at the altitude shown by the instruments of the military apparatus, according to audiences held in Washington.
The American Transportation Security Agency (NTSB) held research hearings from Wednesday to Friday, with advanced interrogations of experts and representatives of the various parts (companies, regulators, air controllers, etc.) concerned about this accident.
The collision, which left 67 dead in total, occurred on January 29 near Ronald’s airport -they watered in the US capital between a Sikorsky Black Black Hawk military helicopter, which carried out a training flight, and a CRJ700 bomber operated by a subsidiary of American Aíneas.
Questions of last February
As of February 14, trusting the data of the flight recorders, the NTSB had reported a “divergence” with respect to the altitude of the helicopter.
Jennifer Homendy, director of the agency, had revealed that, shortly before the collision, the helicopter pilot had reported an altitude of 300 feet, while its pilot instructor indicated 400 feet.
“None of the pilots made a comment about the divergence of altitude,” he said. “At this point, we don’t know why there was a divergence between the two.”
“At the time of collision, Black Hawk was 278 feet. But I want to notice that this does not mean (…) This is what the Black Hawk crew saw in the barometric altimeters in the cabin,” he said, evoking “conflicting information in the data.”
Tests performed
As part of the investigation, they revealed this week’s audience, the tests were held with three copies of the same Sikorsky Black Hawk Lima model, belonging to the same battalion.
They highlighted the differences between the altitude shown by the altimeter by the radar and the barometric altimeter, installed in this device.
In a “controlled environment, the gap was at the tolerated limit of 20 to 55 feet (but), once the rotors were working and produced an elevation and a thrust, the indications of the altimeter (barometric) fell significantly and remained during the entire flight time,” said Marie Moler, one of the researchers, specifying that a “difference of 80 to 130 feet” had not been noticed.
A “very important” gap said
It is a “very important” gap in this case, he insisted Jennifer Homendy with journalists.
“A difference of 100 feet is important,” he added. In fact, in the section where the collision occurred, the helicopters had to fly to 200 feet above sea level.
“I am worried. There is the possibility that what the crew saw was very different from what altitude was actually,” he continued. “This is something we will continue examining,” he said.
Critics aimed at aerial controller
In addition, the criticisms were presented after the accident, when it seemed that the same controller handled helicopter traffic and part of the aircraft traffic in the tower.
According to Clark Allen, an employee of the FAA air regulator who worked until recently in this control tower, this accumulation, authorized by the regulations, was “probably more frequent” than a dissociation of the roles.
He also responded by the question of whether the hierarchical supervision of the tower staff was sufficient that night, he also agreed that the workforce was quite numerous if it had been necessary to dissociate helicopter management.
Source: BFM TV
