Date: 202006
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Weather elements / visibility: Rain; 10
Light: Night
Aircraft: B767 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Fire/Overheat Warning
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Aircraft Aircraft Damaged; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Procedure; Aircraft
Primary problem: Aircraft

Narrative: We were on a cargo flight from ZZZ to ZZZ1. About 10 minutes after reaching cruise altitude; we got a 'Cargo Fire' EICAS message. We notified ATC and immediately headed back to ZZZ. I was Pilot Flying in the left seat doing Captain OE training. The Check Airman was in the right seat; a third pilot (IRO) was in the jumpseat.  The Check Airman was working the radio and handed the QRH to the IRO. They started to run the checklist and I was paying attention to flying the airplane so I was not fully aware of what they were doing. Initially we elected to stay at FL330. We realized later; we had run the wrong checklist. We should have run the Main Cargo Fire checklist. We actually ran the Cargo Fire checklist; which is for the belly cargo area. We realized after the flight; the problem that lead us to do that was there; the EICAS message that was displayed said; 'CARGO FIRE' and that is the name of the checklist we ran. However; there is another checklist called 'MAIN CARGO FIRE'; which is the one for the main cargo deck. but there is no EICAS message that says Main Cabin Fire because that is a system that was added to the plane when it was converted to a freighter.We we heading back to ZZZ and the Check Airman was talking with ATC and the Company. At about that point; we got a Cabin Altitude high warning. We put on the O2 masks and initiated the emergency descent procedure. We descended to 10;000 ft. At this point the Check Airman took over as flying pilot. I looked down at the center console panel and saw that the Main Deck Cargo fire light was on and the Cargo Fire light was on; these were on the Main Deck Cargo Fire Panel. At that point the IRO said he thought we ran the wrong check list; so we ran the Main Cargo Fire checklist. This checklist has you press the CARGO FIRE DEPR switch. We also had a load-master; a mechanic and another IRO on the flight deck. We asked them to look in the main deck cargo compartment door window and see if they see any indication of fire or smoke. They said they did not.About 100 miles from the airport the Check Airman decided to be the flying pilot. I took over the radios and getting the airplane configured and setup to land on RWY 27 in ZZZ. The Wx in ZZZ was SCT clouds with BKN035 at ZZZ. wind was about 160 at 8 kts. The Check Airman decided to land on RWY 27 with a visual approach since that would be the quickest way to get on the ground. As we got close to the airport; we still could not make visual contact because of the low SCT clouds. We got in the clear about 4 miles from the runway. We realized we were too high to make a stabilized approach; so we did a 360 turn to the North to stay clear of the clouds. We made the turn at about 800ft AGL; the Tower gave us an altitude alert; we confirmed we were in visual conditions and had the airport in sight and were staying clear of clouds. ( there was rain in the area moving in). We climbed a few 100ft in the turn and then lined up with the final of RWY 27. We landed on Rwy 27; on short final I noticed we were 15 kts above Vref and called it out. We touched down about 10 kts fast; and we were over landing weight at about 360;000lbs. (max landing weight s 326;000) We rolled to the end of the runway as planned. We had advised the Tower that we wanted the emergency equipment to meet us at the end of the runway. We came to a stop and talked to the Fire Crew Chief. They inspected the airplane and saw no sign of fire and nothing on their IR equipment. We told them we wanted to taxi back to the gate since it was a short taxi and we had no way to safely get of the airplane quickly other than jumping with the inertial reels. As we taxied back; we got a LEFT Engine Fire warning message. We asked the fire chief if they saw any indication of a fire on the left engine. They said no; so he continued.As soon as we parked; we quickly all exited the airplane. The firemen inspected the plane and found no indication of fire. One of the fireman took the temperature of the brakes; he said they were at 1000 degrees. I told them the fuse plugs will probably blow; so people should stand clear. About 2 minutes after that; 4 tires blew their fuse plugs. After we debriefed; we went back to the cockpit to get our things. The mechanics had removed the Fire Control Panel in the center console. They said it;'had a bunch of water in it'. Thinking back after the incident; we did not follow the correct procedures. The checklist; (even the wrong one) said to land at the nearest suitable airport. We elected to go back to ZZZ; because we convinced ourselves there was not really a fire. The only thing we really based that on was that we did not see or smell smoke. But I believe that if a fire was in the main cargo area we probably would not smell anything; because the compartment is sealed. The Check Airman told me after he decided he did not want to go to ZZZZ which was closer than ZZZ because he had a previous experience when he made an emergency landing there and they arrested and held the crew and they don't have good fire fighting equipment. But ZZZ was 160 miles away. I think that fed into him wanted to fly as fast as possible back to ZZZ and then he misjudged the descent and slow down; so we ended up being high and fast close to the airport; and that forced us to make a 360; which just caused more time before landing.Using the wrong checklist probably was caused by us not having any training on the Main Deck Cargo fire emergency procedure in our training program. This is important because it is the one checklist that does not have an associated EICAS message. The pilot reading the checklist saw Cargo Fire on the EICAS and went to the Cargo Fire checklist. But feeding into this was the contradictory indications. We had the EICAS that said Cargo Fire; but that should have been for the lower cargo bays and there should have been a Fire light on that panel; but the MAIN Cargo light on the MAIN Deck panel was the one that was on. Even though none of the LEDs on that panel indicated amber which indicates smoke detected by that sensor. At some point I remember hearing the IRO say; ' this is not making sense; I think we ran the wrong checklist'.I am an electrical engineer and I worked in Flight Test for 8 years before coming back to commercial flying. I have a lot of experience testing aircraft systems. I'm sure that experience was influencing my judgment of the situation. When I started to see contradictory indications; like the MAIN fire light on; but the smoke detectors all showing green; I got the feeling that this was not a fire and was an indication problem. What fed into that; was this plane was known for having indication problems with no underlining failure. So when the Check Airman deiced not to land in ZZZZ which we were right over the top of and instead go back to ZZZ; I was ok with that decision because I was not convinced we had a fire. However; that goes against what we are trained to do and that is to believe your instruments. I believe all of the pilots on board thought it was ok to go back to ZZZ because none of us were convinced we had a real fire. But we were basing that on that we did not see or smell smoke. I guess this is a human performance issue; we don't want to believe a bad situation until we get some kind of proof of it. Also; after the flight the check airman told me when we got close to the airport and were making the visual approach; he still had his O2 mask on and was having trouble scanning the instruments and looking outside; so he took it off. I decided to take mine off when we descended below 10;000ft because there was no smoke in the cockpit and it seemed like ATC was having trouble hearing me. There should be extra training when flying a 767 freighter with a Main Cargo Fire detection system installed. to make it clear to pilots how this system differs from the other fire detection systems on the airplane and show what indication you will get andhow it differs if the fire is in the lower cargo holds.




Synopsis: First Officer reported error made during flight caused by a malfunctioning Fire Warning System; which caused an Air Turnback and Emergency Landing.