Embraer Phenom 300
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Weather
I am captain qualified; but was the SIC on this flight. When starting the aircraft we experienced a STBY HTR FAIL message on the Pilot/Copilot PFD's. This was a repeat write-up and previously addressed by maintenance. I do not know the reason this system failed; from my limited experience in the Phenom 300 this aircraft does not perform well after sitting cold soaked overnight. This aircraft was in the hangar prior to our flight; but I believe it was left outside overnight on the original failure of the system. The Airplane Flight Manual says: NOTE: If the battery has been cold soaked for 2 hours or longer at ambient temperatures of -10C or lower ; it must be preheated to -10 or above prior to engine start.  The AOM Engine Start; operators are directed to start the engines with a GPU when OAT is at or below -10C. At the beginning of this trip I noticed the conflict between the Airplane Flight Manual and the AOM. Knowing I was going to a cold weather area I called the Assistant Chief Pilot for clarification on this procedure. He explained to me that we should get a hangar when possible when cold temperatures were expected; if the plane is to remain outside overnight; we should get a GPU as directed in the AOM. He also said there is no way to tell what temperature the battery is; as there is no indicator on the plane. So operationally; it wasn't feasible to comply with the NOTE in the AFM. This is one of two occurrences this trip having faults with cold soaked Phenom 300's. Always park the plane in a warm hangar if conditions indicate it will be cold soaked. Comply with the AFM NOTE when the plane becomes cold soaked. Develop a procedure for testing the temperature of the aircraft batteries so that the NOTE can be complied with. Maintenance should audit cold soaked Phenom aircraft maintenance faults. Complying with the AFM by parking aircraft inside a hangar and warming batteries will probably lead to less failures and a higher maintenance availability rate.
Phenom 300 First Officer describes problems that arise when the aircraft battery is cold soaked below -10 C.