Date: 201907
Local time of day: 0601-1200
Location: ZZZZ.Airport, FO
Light: Daylight
Aircraft: B777 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: Relief Pilot; Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown
Anomaly: Deviation / Discrepancy - Procedural Hazardous Material Violation; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Passenger Electronic Device
Detector: Person Flight Crew
When detected: Routine Inspection; Pre-flight
Result: General Maintenance Action; General Work Refused; General Flight Cancelled / Delayed
Contributing factors: Procedure; Human Factors
Primary problem: Procedure

Narrative: I was one of the Relief Pilots on Flight XXX. During our preflight paperwork review; all four pilots noted a strange Carry Forward write up in the [Deferred Items List]. The write up read:----------------------------------------Passenger at seat XXL lost mobile phone under the seat. Mobile phone rang but couldn't [be] located.----------------------------------------Our discussion centered on the potential safety concerns with flying with a lost phone in the aircraft; and in this case; lost under/near a business class seat; with all of the moving parts that could damage the phone and start a thermal runaway.The Captain asked each pilot if they were comfortable flying the aircraft with this issue; and the consensus was that we were not comfortable; and that the phone had to be found before we would take the aircraft on a 10 hour; 138 minute ETOPS overwater segment.The Captain initiated a phone call with Dispatch; informing them of our intent to refuse the aircraft until the phone was found. I was not present for the entire phone call; but the Captain relayed that there was a conference call with Dispatch; [Maintenance Control] and the [Chief Pilot] to discuss the write up and our concerns about operating the aircraft with this potential hazard. At the end of the call the Captain confirmed with all parties that we would refuse to operate the aircraft until the phone could be located.The Pilot Monitoring entered the appropriate [Fault Reporting Manual] code for aircraft refusal into the Electronic Logbook and sent it to [Maintenance Control].The aircraft was de-boarded and Maintenance commenced a search for the phone. This included taking apart the [cabin] compartment at seat XXL; as well as removing cargo from the Forward Cargo Compartment to prepare to search the ceiling area near the seat location. Approximately 2 hours and 30 minutes after our original push time the phone was located in the area under the seat; and it took another 10-15 minutes to actually retrieve the phone. The phone was still powered on when it was found!The [Maintenance Release] was cleared to reflect the resolution of the maintenance item and we departed ZZZ1 approximately 3 hours late.There are a couple of very important additional details to discuss regarding this event:First; during our investigation into the Carry Forward write up; we discovered that the phone was lost on a previous flight to ZZZ. The Carry Forward was added to the maintenance history in ZZZ. That aircraft subsequently flew a segment from ZZZ to ZZZ1; where it remained overnight prior to our flight.It is very concerning to consider the huge risk that was introduced into our Safety Management System by allowing an aircraft to fly an ETOPS segment with this potential hazard on board. The fact that [Maintenance Control] categorized it as a Carry Forward had the potential of normalizing a very hazardous situation. We looked at the [Maintenance Release] for the inbound flight to ZZZ1 and discovered the Carry Forward in their [Deferred Items List] as well; which meant that the crew either questioned the write up and concluded that it was ok; or they didn't notice/realize the hazard.Second; this aircraft was on the ground for 4.5 hours in ZZZ after the original write up; and it was on the ground in ZZZ1 for nearly 14 hours before our flight. ZZZ1 Maintenance confirmed to us that they had not taken any actions to locate the phone prior to our refusal to operate the aircraft.Third; the Captain told the rest of the Flight Deck crew that during his conference call; he was frustrated that [Maintenance Control] did not see a safety hazard from the cell phone missing in the aircraft. This lack of concern from a safety standpoint is confirmed by the simple fact that the original write up was classified as a Carry Forward; with no action taken by Maintenance after the initial search. There were several hours in ZZZ before the flight to ZZZ1 and over 12hours in ZZZ1 where maintenance personnel could have undertaken a search to find it. The Captain replayed that the [Maintenance Control] participant on the call stated that they had 3 days to find the phone; so he was not concerned yet that it was missing. When the Captain queried him as to the reason for giving Maintenance 3 days to find it; [Maintenance Control] said that the 3-day limit was in order to satisfy Customer Service metrics on returning the phone to the customer; and had nothing to do with a potential hazard to flight from a lithium ion battery device missing underneath the passenger cabin in the aircraft.I am deeply--deeply concerned by [Maintenance Control]'s complete lack of awareness that this missing phone constituted a potential catastrophic hazard to flight. The fact that the write up was classified as a Carry Forward and a new [Maintenance Release] issued for the [previous] flight scares me to the core. [The company] accepted a huge and unnecessary risk to passenger and crew safety by operating Flight XXY. Until this event happened to us I would have never considered that [the company] would knowingly accept such an unnecessary risk.There are far too many examples of lithium ion battery hazards to flight for this to have happened on these flights. It is completely unacceptable to me as a professional pilot.




Synopsis: B777 First Officer reported Captain refused assigned aircraft citing safety concerns regarding a lost mobile phone in the passenger cabin.