Editor's Note:
The National Transportation Safety Board has issued its latest
update on the board's investigation of the September 29 midair
collision over the Amazon Jungle of a Gol Airlines Boeing 737 and
an Embraer Legacy 600 business jet.
In the update, which follows below, the NTSB says both the
Legacy and the airliner were cleared to FL370. According to the
flight plan filed by the Legacy's pilots, however, the bizjet was
supposed to descend to FL360, and then climb to FL380, before it
crossed paths with the Brazilian plane. The pilots did not request
either altitude change... and ATC did not direct the pilots to move
to a different altitude.
The board also found that communications between Brazilian
controllers and the Legacy became increasingly erratic; at one
point, the Embraer's pilots tried to contact ATC 12 times, without
success. Controllers also stopped receiving the Legacy's
transponder code before the collision.
The government of Brazil has asked the National Transportation
Safety Board to disseminate the following factual information on
the progress of its investigation into a midair collision over the
Brazilian Amazon jungle on September 29, 2006, between a Boeing
737-800 (PR-GTD) operated by Gol Airlines of Brazil, and an Embraer
Legacy 600 business jet (N600XL) owned and operated by Excelaire of
Long Island, New York.
The accident investigation is being conducted under the
authority of the Brazilian Aeronautical Accident Prevention and
Investigation Center (DIPAA). Under the provisions of ICAO Annex
13, the United States, as state of registry and operator of the
Excelaire Legacy, and state of manufacture of the Boeing 737 and
Honeywell avionics equipment in both airplanes, has provided an
accredited representative and technical advisors for the
investigation. The U.S. team includes the accredited representative
from the major aviation accident investigations division of the
NTSB, as well as technical advisors in operations, systems, air
traffic control, flight recorders, and aircraft performance.
Additional technical advisors from Boeing, Excelaire, Honeywell,
and FAA have also been included.
The accident occurred about 4:57 pm Brasilia standard time.
The Boeing 737 was destroyed by in-flight breakup and impact
forces; all 154 occupants were fatally injured. The wreckage of the
737 was located in remote jungle terrain with very difficult
access. Brazilian military search and rescue personnel have located
the flight recorders and all significant portions of the wreckage
except the outer portion of the left wing. The Legacy N600XL
experienced damage to its left wing and left horizontal stabilizer
and performed an emergency landing at the Cachimbo Air Base,
approximately 60 miles northwest of the collision site. There was
no further damage to the airplane, and the 2 crew members and 5
passengers were not injured. The airplane remained at the base and
significant components have been tested and recovered from the
aircraft.
Visual meteorological conditions prevailed in the area of the
accident. Both aircraft were operating on instrument flight rules,
on instrument flight plans and clearances.
The Boeing 737 was a scheduled domestic air carrier flight
enroute from the Eduardo Gomes International Airport, Manaus,
Brazil; to the Presidente Juscelino Kubitschek Airport, Brasilia.
The Legacy N600XL was enroute from the Prof. Urbano Ernesto Stumpf
airport, San Jose dos Campos, Brazil (SBSJ), to a stopover in
Manaus, and eventually enroute back to the U.S. This was
Excelaire's initial flight with this aircraft, taking delivery from
the Embraer factory and a planned flight to Excelaire's home base
in New York.
History of flights:
The Legacy N600XL departed SBSJ at about 2:51 pm. The filed
flight plan included a routing via the OREN departure procedure to
Pocos beacon, then airway UW2 to Brasilia VOR (BRS), airway UZ6 to
Manaus. The cruise altitude was filed as FL370, with a planned
change to FL360 at BRS, and to FL380 at the TERES navigational fix,
approximately 282 miles north of BRS.
After takeoff, N600XL was issued a number of interim altitudes
during climb, all of which were read back. The flight was cleared
to proceed direct to Araxa VOR (on airway UW2), and at 3:11 pm was
cleared to climb to FL370. At 3:33 pm, the airplane leveled at
FL370.
At 3:35 pm, the Boeing 737 departed Eduardo Gomes airport,
requesting FL370 as a cruise altitude, and a routing via UZ6 to
BRS. The airplane reached FL370 at 3:58 pm. There were no anomalies
in communications with or radar surveillance of the Boeing 737
throughout the flight.
At 3:51 pm, an air traffic controller in the Brasilia ACC
(CINDACTA 1) instructed N600XL to change frequencies to the next
controller's sector. The crew of N600XL reported in on the assigned
frequency that the flight was level at FL370. ATC acknowledged and
instructed the crew to "ident" (flash their transponder). Radar
indicates that the ident was observed. This was the last two-way
communication between N600XL and ATC. At this time the airplane was
approximately 40 nautical miles south of BRS.
At 3:56pm the Legacy N600XL passed BRS level at FL370. There is
no record of a request from N600XL to the control agencies to
conduct a change of altitude, after reaching flight level 370. The
airplane made calls, but there is no communication in which it
requested a change of flight level. There is also no record of any
instruction from air traffic controllers at Brasilia Center to the
aircraft, directing a change of altitude.
When the airplane was about 30 miles north-northwest of BRS, at
4:02 pm, the transponder of N600XL was no longer being received by
ATC radar. A transponder reports a unique code, aiding radar
identification, and provides an accurate indication of the
airplane's altitude. Additionally, the transponder is a required
component for the operation of Traffic Collision Avoidance System
equipment, commonly called the TCAS system.
Between 3:51 pm and 4:26 pm, there were no attempts to establish
radio communications from either the crew of N600XL or ATC. At 4:26
pm the CINDACTA 1 controller made a "blind call" to N600XL.
Subsequently until 4:53 pm, the controller made an additional 6
radio calls attempting to establish contact. The 4:53 call
instructed the crew to change to frequencies 123.32 or 126.45. No
replies were received.
There is no indication that the crew of N600XL performed any
abnormal maneuvers during the flight. Flight Data Recorder
information indicates that the airplane was level at FL370, on
course along UZ6, and at a steady speed, until the collision.
Primary (non-transponder) radar returns were received corresponding
to the estimated position of N600XL until about 4:30 pm. For 2
minutes, no returns were received, then returns reappeared until
4:38 pm. After that time, radar returns were sporadic.
Beginning at 4:48 pm, the crew of N600XL made a series of 12
radio calls to ATC attempting to make contact. At 4:53, the crew
heard the call instructing them to change frequencies, but the
pilot did not understand all of the digits, and requested a repeat.
No reply from ATC was received. The pilot made 7 more attempts to
establish contact.
At 4:56:54 pm the collision occurred at FL370, at a point about
460 nautical miles north-northwest of BRS, on airway UZ6.
There was no indication of any TCAS alert on board either
airplane, no evidence of pre-collision visual acquisition by any
flight crew member on either aircraft, and no evidence of evasive
action by either crew.
Wreckage and damage examination indicates that it is likely the
left winglet of the Legacy (which includes a metal spar) contacted
the left wing leading edge of the Boeing 737. The impact resulted
in damage to a major portion of the left wing structure and lower
skin, ultimately rendering the 737 uncontrollable. Flight recorder
information ceased at an approximate altitude of 7,887 feet.
After the collision, the crew of N600XL made numerous further
calls to ATC declaring an emergency and their intent to make a
landing at the Cachimbo air base.
At 5:02 pm, the transponder returns from N600XL were received by
ATC.
At 5:13 pm, an uninvolved flight crew assisted in relaying
communications between N600XL and ATC until the airplane
established communication with Cachimbo tower.
Investigative activities completed to date:
Flight recorders from both airplanes were recovered and
downloaded at the Transportation Safety Board of Canada (TSB)
laboratories. Transcriptions of the cockpit voice recorders (CVRs)
were prepared (the transcript of the Legacy's CVR was produced at
the NTSB's laboratory in Washington, D.C.) and data from flight
data recorders obtained.
Initial interviews and medical examinations were conducted with
the crew of the Legacy. Air Traffic Control data was gathered.
Preliminary tests of the avionics equipment on the Legacy were
performed. Wreckage of the 737 was examined.
Future investigative activity:
Additional investigative work will include laboratory tests of
the avionics components removed from the Legacy, an examination of
the operating procedures of the avionics, interviews with ATC
personnel, examination of ATC practices and comparison between
Brazilian and FAA procedures, a technical examination of ATC
communication and surveillance systems, and further examination of
the training provided to the operators.
The Investigator in Charge estimates a 10-month timeline for the
investigation. The first phase, data gathering is estimated to take
approximately 45 days, although some further data gathering remains
to be completed. Analysis of the data is estimated to take 90 days
followed by a preliminary report with conclusions 120 days
afterward.
Preparation of the final report and review by involved parties
and States is estimated at a further 30 days each.