Date: 202009
Location: ZZZ.ARTCC, US
Aircraft: B787-900
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Air Conditioning and Pressurization Pack
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Relief Pilot; First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Physiological - Other
Second reporter function: Pilot Not Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Attendant; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Aircraft Equipment Problem Dissipated; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; Flight Crew Overcame Equipment Problem; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Cruising at FL 410 and Pack L EICAS message annunciation. Left pack cycled on and off and resulted in a burning rubber smell as reported by cockpit and cabin crew. Notified ATC and conferred with Maintenance Control and turned left pack off. Smell subsided and made a precautionary landing at ZZZ. Airport Fire Department followed aircraft to the gate and aircraft taken out of service. Numerous headaches reported by crew. The Captain stated that he smelled something after engine start up but the First Officer and First Officer #2 did not. If we had better olfactory senses maybe we would have.


Second narrative: On engine start Captain noticed a very faint burning smell. He asked his 2 FO's (First Officers) if they smelled a burning smell; they responded 'no' to burning and 'yes' to musty odor. Smell went away on taxi and all operations normal until cruise at FL 410. First indications were separate L1 and L2 status messages followed by a rumbling sensation and noise felt throughout the entire aircraft by all crew; next L Pack EICAS message. Immediately requested FL 240 in case we lost other pack and started the Emergency Checklist. At the same time we noticed a burning smell in both cockpit and cabin. I was surrounded by emergency airport options. We asked ATC to return to ZZZ. Due to increasing burning smell; Captain notified ATC. Cockpit began working the problem. The plan was to proceed to ZZZ but we were overflying ZZZ1 on that route and we would land ZZZ1 if unable to gain control over burning odor. When the left pack was inoperative the smell would subside. The problem was that the L Pack Emergency checklist entailed a reset procedure which would command the system to try resets of the L pack. When the L pack would reset (for about 30 seconds before it tripped again) the strong burning smell would reappear. Captain realized he would have to physically turn off the left pack; contrary to the L pack checklist procedure. Captain placed Sat Com with Maintenance through Dispatch and they confirmed manually taking the pack off line (All of this occurred within minutes). FO was flying and working the checklist and Captain had the [other] First Officer talk to ATC and the flight attendants. Captain made P/A to passengers informing them that we were returning to ZZZ since the aircraft could not cross the Atlantic single Pack. Captain informed the flight attendants we would be making a precautionary landing in ZZZ. Although we were working the problem and headed to ZZZ we were not sure if we would be landing ZZZ1 or ZZZ. Pulled up both airports and did landing analysis on both airports. Once we physically turned off the left pack the burning smell dissipated completely and we told Dispatch and ATC we would be landing ZZZ. Landed uneventfully in ZZZ and taxied aircraft to the gate. Captain's compliments to the entire crew and specifically the 2 F/O's for their professionalism and skills.


Synopsis: B787 flight crew reported a fumes event at cruise flight level resulting in a return to the departure airport.