I don't have the full English text yet of the report on the Sept. 29 mid-air disaster that ExcelAire sent to Brazilian authorities to summarize its case that the 2 American pilots did not cause the accident. (The full PDF text in Portuguese is linked in yesterday's post).
But thanks today to our man in Sao Paulo, Richard Pedicini, who's been assiduously translating it, here are highlights of documentation ExcelAire can cite and charges it will make in its own defense as Brazilian authorities continue their campaign to scapegoat the Americans:
- As has long been known, air traffic control at departure in San Jose dos Campos authorized the Legacy to fly at 37,000 feet all the way to its destination Manaus (which involved passing through Brasilia ATC space)
- Air traffic control in Brasilia was negligent in not contacting the Legacy pilots to tell them to descend to 36,000 feet, or to acknowledge that the jet was at 37,000 feet.
- Air traffic control in Brasilia was negligent in not adopting "standard procedures" to notify the Legacy pilots that their transponder was not signaling, even though they [the controllers] were aware of this fact.
- Even after the "total loss" of the Legacy signal on both primary and secondary radars, air traffic control in Brasilia negligently failed to secure a 2,000-foot minimum separation between the Legacy and the oncoming Gol Airlines 737.
- Air traffic control in both the Brasilia and Amazonas centers made errors during the coordination of handover of the Legacy from one region to the other.
"Analysis of the air traffic control transmissions and the Legacy's cockpit recorder confirm that both of the aircraft had been cleared by Air Traffic Control to fly at the same altitude and in the same airway, in opposite directions. As demonstrated, though this collision course had been established more than an hour before the accident, a series of failures in the air traffic control system impeded the controllers responsible for these two aircraft [in] noting the error in time to avoid the tragedy," the ExcelAire report says.
The report also addresses the flight plan that was, as is normal procedure in international aviation, superseded when ATC issued different orders:
"Besides the problems with the Legacy's avionics components, determining failures by Air Traffic Control were pointed out. This accident occurred under instrument flight rules (IFR) in controlled air space. Under those conditions, aircraft movement, both horizontal and vertical, is subject to the authorizations of air traffic controllers. An authorization is an obligatory instruction for an aircraft, which must be followed, except in case of an emergency.
"In this specific case, before takeoff, Embraer transmitted the Legacy's flight plan electronically to air traffic control, supplying, among other data, the proposed flight route and the altitudes for the trip from São José dos Campos (SBSJ) to Manaus. The plan proposed: (a) cruise altitude of 37.000 feet from SBSJ to Brasilia; (b) after Brasilia, descent to 36,000 feet to point Teres, approximately 228 nautical miles northwest of Brasilia; (c) at Teres, ascent to a cruise altitude of 38,000 feet to Manaus. Soon after takeoff, however, air traffic control authorized the Legacy to ascend and maintain 37,000 feet, and, after this, there were no other authorizations for change of altitude.
"The Legacy's position was monitored by means of secondary signals from radar surveillance, which uses information supplied by transponder mode C to identify the aircraft on the air traffic control radar and inform its altitude. That information appears in a data block on the screens of air traffic control ("data block"), where the planned altitudes for the distinct flight segments also appear.
"About two minutes before the Legacy reached Brasilia, although the data block indicated that an altitude change had been planned, the controller did not alter its authorization for the Legacy to maintain a cruising altitude of 37,000 feet.
"Approximately 5 minutes after passing Brasilia, and 55 minutes before the accident, air traffic control stopped receiving the Legacy's mode C transponder signal. The loss of the Legacy's signal appeared on air traffic control's data block, but, in violation of the basic rules of aviation, the controller responsible did not communicate that fact to the pilots, so that they could verify their transponder or switch to the other transponder. The controller also erred in failing to communicate the transponder's inoperative state to another controller, and in failing to coordinate a non-radar separation of the Legacy along its planned flight route."
The report stresses ExcelAire's determination not to assign guilt but to fully document the chain of causes of the accident "in order to prevent similar occurrences in the future."
Among recommendations, some of which that have already been made by international investigators looking into the fiasco, the report suggests:
- Greater English-language proficiency by Brazilian air traffic controllers
- Better training in crisis management, including procedures to follow when a transponder of an aircraft being handled stops signaling
- "Modification of [Brazilian] air traffic control displays to eliminate confusing and unnecessary data" that can cause operators to misread a plane's actual altitude
- ATC center equipment that more clearly displays the loss of "secondary radar signals" from the screens that determine actual altitude
- Better training of controllers on taking "decisive action" to locate an aircraft during a loss of radio and/or radar contact
The Legacy pilots, the report says, "did not receive through the flight instruments located on the aircraft any indication of problems related to avionics components." [My note: That's a reference to the malfunctioning transponder unit]
"At no time during the flight did the TCAS collision-avoidance signal appear on the control panel. The safety investigation also confirmed that the Air Traffic Control Center [in Brasilia] received various radio calls made by the Legacy, but did not answer."
The report goes on to address in detail what ExcelAire considers defects in avionics equipment on the Legacy, including faulty connections between the antenna and the transponder. It also asserts that the Radio Management Unit (RMU) and the Communications Unit (RCZ) "were not new components" and that the RMU, which is key to a functioning transponder, "had already presented failures in two other aircraft before being installed in the new aircraft sold to ExcelAire by Embraer."
"The RCZ, which includes the Mode C transponder, had also been rejected in another aircraft before being installed in the Legacy," the report asserts.
***
Suddenly, it seems, the ball is in another court. When response is available from Embraer and Honeywell -- the transponder manufacturer -- I'll post it.
Meanwhile, I'm still hoping to post an English link soon to the whole 20,000-word text for those of you, including so many pilots who have remained in touch with me over this sad event, who want to know just precisely how one sorry mistake after another on the ground added up to cause the worst aviation disaster in Brazil's history.
--end
No comments:
Post a Comment