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ASN Wikibase Occurrence # 232459
Last updated: 26 January 2020
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Date:06-APR-2018
Time:22:40 UTC
Type:Silhouette image of generic B738 model; specific model in this crash may look slightly different
Boeing 737-8EH (WL)
Owner/operator:GOL Transportes Aéreos
Registration: PR-GGE
C/n / msn: 35851/3745
Fatalities:Fatalities: 0 / Occupants: 173
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:Rio de Janeiro - Belo Horizonte -   Brazil
Phase: En route
Nature:Domestic Scheduled Passenger
Departure airport:Rio de Janeiro-Santos Dumont Airport, RJ (SDU/SBRJ)
Destination airport:Belo Horizonte-Tancredo Neves International Airport, MG (CNF/SBCF)
Investigating agency: CENIPA
Narrative:
The aircraft, a Boeing 737-800, was prepared to perform a regular service from the Santos Dumont Airport (SBRJ), Rio de Janeiro, Brazil, to the Tancredo Neves International Airport near Belo Horizonte.
During the previous flight, problems were noted with the bleed air system. After a maintenance check the aircraft was released for service. However, during taxi, the DUAL BLEED light illuminated. The aircraft returned to the stand and was again attended by maintenance. After 70 minutes the aircraft was dispatched with Bleed 1 inoperative, according to the MEL. During the time on the ground the air conditioning was not working, causing the temperature in the cabin to rise considerably.
At about 22:30 UTC the flight took off with 6 crew members and 167 passengers on board. The take-off was performed with Bleeds 1 and 2 in OFF; the APU Bleed in ON; Packs 1 and 2 in AUTO and the Isolation Valve in OPEN.
After take-off, the crew put Bleed 2 ON; Pack 2 OFF; the Isolation Valve in CLOSE and the APU Bleed in OFF. This configuration prevented Pack 1 from receiving bleed air from Bleed 2 and the aircraft pressurization. The aircraft slowly depressurized.
At about 1 minute and 33 seconds after reaching FL250, the cabin altitude alert sounded, indicating that the atmospheric pressure inside the aircraft had reached values compatible with altitudes above 10,000ft.
The crew began the descent to the FL100 (10,000ft), during which the oxygen masks of the passengers’ cabin fell down automatically. Upon reaching FL100, the situation was normalized. The crew continued the descent to FL090 and the flight continued on that level up to the destination. The aircraft landed safely.

Contributing factors.
- Attention – a contributor.
The attention of the pilots was fixed only on a few parameters to determine whether the aircraft was being pressurized, which, together with the lack of knowledge of the system, prevented them from broadening the analysis of the situation and taking the necessary actions to correct the problem.
- Attitude – a contributor.
The performance of the commander in functions that competed to the copilot (Pilot Monitoring), in some moments of the flight, as in the configuration of the pressurization panel, even without consulting the MEL, indicated an attitude of nonobservance regarding the procedures prevised in the operation manual, which interfered with the cabin coordination for the problem management.
- Communication – a contributor.
There was no effective communication between the pilots, which affected the crew's ability to identify and correct the problem in a timely manner to avoid depressurizing the aircraft.
Interventions made by the copilot with the commander about the correct operation of the pressurization system were not sufficiently assertive to the point where the commander was doubtful of the procedures they performed. In contrast, the commander, in this interaction, remained convinced about the actions taken, generating compliance in the copilot.
- Crew Resource Management – a contributor.
Tasks related to the pressurization panel configuration were associated with the Pilot Monitoring function (copilot at that time). However, the Pilot Flying (commander at that time) took the initiative to set the panel shortly after take-off. The configuration was performed from memory without consulting the MEL. This fact denied the division of tasks and contributed to the pilots not realizing the error they were making in the configuration. During the moments of doubt in the flight, the Pilot Flying was the one who read the MEL, a task that should be performed by the Pilot Monitoring.
- Team dynamics – undetermined.
The way in which the collaboration and cooperation took place in flight, although subtly, led to an informal climate, which failed to consider the responsibilities formally established for the crew, allowing the commander (Pilot Flying on this flight) to execute actions related to the Pilot Monitoring function, in addition to performing procedures based from memory.
This dynamic of the crew may have made it difficult to identify the real problem of the aircraft pressurization system.
- Emotional state – undetermined.
The flight delay, with the organizational implications and the special aircraft dispatch condition, generated a work overload, which may have increased the level of stress in the cabin to the point of confusion in the reading of the MEL procedure, as well as it may have affected the performance of the pilots in the management and configuration of the aircraft pressurization system.

Sources:

CENIPA

Accident investigation:
cover
  
Investigating agency: CENIPA
Status: Investigation completed
Duration: 1 year and 9 months
Download report: Final report


Revision history:

Date/timeContributorUpdates
26-Jan-2020 13:21 harro Added

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