EMB ERJ 170/175 ER/LR
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Troubleshooting; Workload
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action
Aircraft; Human Factors; Procedure
On the approach into ZZZ; already cleared to land via Tower and under visual conditions; we got a blue message on EICAS that stated 'CRG FWD FIREX HI ARM'.  Me and the Captain discussed our options and decided that continuing to land would be our best option. I called the flight attendants in the back to make sure they didn't smell any smoke or realize any abnormalities which they both confirmed they hadn't! The blue Message on the EICAS actually was cleared away prior to our landing. Upon landing; we advised operations of what happened and told them to proceed with care.  once at the gate; the Captain wrote the event in the logbook for further inspection by maintenance.
We planned and briefed a visual approach to [Runway] XXL. About 20-25 miles from ZZZ; we were cleared by ATC for the visual approach to XXL. We immediately turned direct for the visual approach.Shortly after crossing the far (north) shoreline; at about 12 nm WNW of ZZZ; we were over the water; still on a heading to intercept final; when the following EICAS Advisory (cyan) message appeared: 'CRG FWD FIREX HI ARM'. Associated with this was the illumination (in red) of the FWD CARGO fire extinguisher pushbutton; which indicated that the high-rate cargo fire bottle had indeed armed.We were on the lookout for the EICAS Warning (red) message CRG FWD SMOKE; but this NEVER appeared. Because of the lack of any Warning (red) or Caution (yellow) EICAS message and because there was NO secondary abnormality or indication of ANY kind (no other system failure indication and neither the pilots nor the FAs smelled smoke); we did not press the illuminated FWD CARGO fire extinguisher button. We want to emphasize that if a SMOKE condition HAD been sensed- or if smoke or fire had been reasonably-suspected by the crew; we would have IMMEDIATELY pushed the illuminated FWD CARGO fire extinguisher button (to discharge the high-rate bottle immediately followed automatically by the low-rate bottle one minute later) per the Immediate Action Card (IAC); and then transitioned to the Quick Reference Handbook (QRH) checklist. But since there was no Smoke/Fire Condition sensed or reasonably-suspected; we did not go this route.Instead; the PF took the radios and instructed the PM to look in the QRH for anything related to the 'CRG FWD FIREX HI ARM' advisory (cyan) EICAS message; but there was zero guidance. There were also no cargo fire detection system failure messages on EICAS. The PM then called the FAs to inquire as to whether or not they smelled any odors or observed smoke of any kind. Neither the pilots; FAs; nor passengers; sensed nor observed any visible smoke or discernible abnormal odors (NOTE: only FAs were asked about odors; NOT the passengers; but we assume the passengers would have told the FAs if they had sensed something). Indeed; the Advisory (cyan) EICAS message disappeared about 30-40 seconds after it appeared; along with the FWD CARGO fire extinguisher push button ceasing to illuminate. This indicated to us that we had potentially made the right call and a SMOKE/FIRE Condition in the FWD CARGO BAY had indeed NOT BEEN DETECTED.The PM and PF discussed their options; and decided the safest option was to continue with the visual approach without pressing the illuminated FWD CARGO fire extinguisher button; BUT also BE READY TO PRESS that button; Declare Emergency; call for Fire Trucks; and continue for immediate landing IF either the Warning (red) EICAS message or ANY secondary indication were to appear. The existing clearance for visual approach was already the most expeditious landing clearance possible; and would get us on the ground the fastest if anything was to go wrong.After landing; as an additional measure of caution; we told Station to alert Ramp Agents to use extreme caution when opening the FWD Cargo Door; just in case there was somehow smoke; odors; or Halon in that bay. After Block-In and during the regular post-flight walk-around inspection; neither the CA nor any Rampers observed ANY signs of fire; smoke; nor odors in; nor discharged Halon extinguisher into; the Fwd Cargo Bay. After the flight; we debriefed with both Rampers and Flight Crew; called Maintenance Control and also warned the next flight crew (who was swapping into the aircraft) about what we had observed.  We planned and briefed a visual approach to XXL. About 20-25 miles from ZZZ; we were cleared by ATC for the visual approach to XXL. We immediately turned direct for the visual approach.After landing; as an additional measure of caution; we told Station to alert Ramp Agents to use extreme caution when opening the FWD Cargo Door; just in case there wassomehow smoke; odors; or Halon in that bay. After Block-In and during the regular post-flight walk-around inspection; neither the CA nor any Rampers observed ANY signs of fire; smoke; nor odors in; nor discharged Halon extinguisher into; the Fwd Cargo Bay. After the flight; we debriefed with both Rampers and Flight Crew; called Maintenance Control and also warned the next flight crew (who was swapping into the aircraft) about what we had observed.This was a tough judgement call.An argument could be made to press the illuminated FWD Cargo fire extinguisher push button; immediately; as soon as it illuminates; even WITHOUT ANY 'CRG FWD SMOKE' EICAS Warning (red) message; as the arming of the fire bottle may be the sole (or advance) indication of a SMOKE or Fire condition.However; the cargo fire protection system is designed so that if all sensors are operational; several sensors must independently sense smoke before the fire detection system determines that a SMOKE Condition exists (resulting in 'CRG FWD SMOKE' EICAS Warning [red] message). Indeed; the QRH has a checklist for EICAS-annunciated 'CRG FWD SMOKE' Warning [red] message; not for Advisory (cyan) or Caution (yellow) messages related to Cargo Smoke.In addition; blowing the fire extinguisher bottles unnecessarily comes with its own issues (albeit with less serious consequences); such as ruining loss of luggage; death of any live animals in FWD Cargo Bay; and small safety hazard to ground crew opening the FWD Cargo door (due to lingering extinguishing material in the bay); following an in-flight discharge of fire extinguisher(s) into that bay. After a call to Maintenance Control; they suspected some sort of fault in the system; but that is unconfirmed.We believe we made the right judgement call; and the entire fellow flight crew- both the FO and FAs- are to be commended for assisting the CA in making the best decisions for safety of flight and ground crew.
EMB-175 flight crew reported a forward cargo compartment fire extinguishing system armed light and elected to continue the approach to landing. There was no evidence of smoke or flames when the compartment was opened by ramp personnel.