B757 first officer reported troubleshooting an environmental control system problem that caused the ...

Attributes
ACN	1554689
Time
Date	201806
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Cooling Fan any cooling fan
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 198 Flight Crew Total 5571 Flight Crew Type 1557
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Procedural Weight And Balance

Narrative:

Brief; preflight; push; and taxi were uneventful. Crossing the hold-short for takeoff; the cockpit began to feel warm and there was a slight but noticeable loss of airflow. No abnormal EICAS or status messages were present; and I have experienced ecs (environmental control system)-related anomalies similar to this in the past; so I did not feel uncomfortable taking the airplane flying. During the takeoff roll; the normal sound of cockpit cooling air and equipment cooling air largely disappeared; and the smell of fuel fumes was present. It was abnormally quiet on the takeoff roll and I started this at around 50 knots; but again; with no malfunctions present on EICAS; we elected to continue the takeoff roll. Climbing through approximately 6000 ft.; the captain cycled both recirculation fan switches. Had I known that he was going to cycle the left recirculation fan switch I would have objected; because cycling that switch opens the overboard exhaust valve. With no ability to close the overboard exhaust valve while airborne; we were unable to pressurize the aircraft; limiting us to 10000 ft. MSL and requiring an air return. We coordinated with ATC; dispatch; maintenance; operations; and our in-flight crew for a return and [had] an overweight landing.

Original NASA ASRS Text

Title: B757 First Officer reported troubleshooting an environmental control system problem that caused the aircraft to lose its ability to pressurize; resulting in an overweight landing at the departure airport.

Narrative: Brief; preflight; push; and taxi were uneventful. Crossing the hold-short for takeoff; the cockpit began to feel warm and there was a slight but noticeable loss of airflow. No abnormal EICAS or status messages were present; and I have experienced ECS (Environmental Control System)-related anomalies similar to this in the past; so I did not feel uncomfortable taking the airplane flying. During the takeoff roll; the normal sound of cockpit cooling air and equipment cooling air largely disappeared; and the smell of fuel fumes was present. It was abnormally quiet on the takeoff roll and I started this at around 50 knots; but again; with no malfunctions present on EICAS; we elected to continue the takeoff roll. Climbing through approximately 6000 ft.; the Captain cycled both recirculation fan switches. Had I known that he was going to cycle the left recirculation fan switch I would have objected; because cycling that switch opens the overboard exhaust valve. With no ability to close the overboard exhaust valve while airborne; we were unable to pressurize the aircraft; limiting us to 10000 ft. MSL and requiring an air return. We coordinated with ATC; dispatch; maintenance; operations; and our in-flight crew for a return and [had] an overweight landing.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

B757 first officer reported troubleshooting an environmental control system problem that caused the aircraft to lose its ability to pressurize; resulting in an overweight landing at the departure airport.