INFLT ENCOUNTER WITH ICE NEARLY PRECIPITATES CFIT IN DESIGNATED MOUNTAINOUS TERRAIN AREA.

Narrative

WHILE ON A VFR FLT FROM MERRILL FIELD (MRI) TO MONTAGUE ISLAND; THE WX CAME DOWN TO BELOW TERRAIN HEIGHT (TERRAIN HEIGHT=6500 FT; CEILING CAME DOWN TO 4500 FT). I DECIDED TO TKOF FROM THE BEACH VFR AND FILE IFR ENRTE TO MAINTAIN POSITIVE TERRAIN CLRNC. THE AREA FOR 50 MI IN ANY DIRECTION WAS MOUNTAINOUS AND GLACIER COVERED; WITH NO LNDG SITES OR TOWNS WITHIN ABOUT 60 NM. THE NEAREST TOWN WAS SEWARD; AK; WITH NO INST APCH AVAILABLE IN SEWARD. FUEL AT THE TIME OF TKOF WAS ADEQUATE FOR THE EXPECTED DURATION OF THE FLT WITH APPROX 2 HRS OF RESERVE. TKOF WAS UNEVENTFUL AND CLB TO MEA OF 10000 FT MSL WAS BEGUN. DURING CLB WE FILED IFR WITH ZAN. AROUND 8000 FT MSL WE BEGAN TO ACCUMULATE LIGHT RIME ICE. WE CONTINUED CLBING TO AN ALT OF 9700 FT MSL; OUR HIGHEST OBTAINABLE ALT WITH THE ICING DEGRADING ACFT PERFORMANCE. OUR CLB FOR THE LAST 1500 FT WAS REDUCED TO A RATE BTWN 100 AND 25 FPM. I SHOULD HAVE RPTED INABILITY TO CLB TO CTR BUT NEGLECTED TO DO SO BECAUSE OF CONCENTRATING ON EXACTING THE BEST PERFORMANCE POSSIBLE FROM THE ACFT. I RPTED TO CTR OUR INABILITY TO MAINTAIN OUR ASSIGNED ALT; AT WHICH TIME CTR AMENDED OUR ALT TO 9000 FT (MOCA WAS 8500 FT). AFTER A TIME; I RPTED UNABLE TO MAINTAIN 9000 FT AND WAS GIVEN 8500 FT ASSIGNED ALT BY CTR. ICING AT 8500 FT WAS ACCUMULATING AT AN EXCITING RATE. WE THEN CANCELLED IFR AND DSNDED VFR TO 6500 FT MSL WHICH I KNEW TO BE ABOVE TERRAIN AT THIS POINT. WE WERE STILL CARRYING A LOT OF ICE AND WERE DODGING CLOUDS. ACFT PERFORMANCE WAS DEGENERATED TO THE POINT WHERE WE WERE ABLE TO MAINTAIN 80 MPH INDICATED IN LEVEL FLT AT 6500 FT MSL. WE THEN FOUND A POCKET OF 'GOOD' VFR AND DSNDED INTO A VALLEY AND CONTINUED THE FLT TO MRI UNEVENTFULLY. SUPPLEMENTAL INFO FROM ACN 251742: DECIDED TO FILE IFR FOR MORE DIRECT ROUTING. WE WANTED DIRECT BECAUSE FUEL WAS A FACTOR. EARLIER WX RPTS WERE EXCEEDINGLY INCORRECT; CALLING FOR MUCH BETTER WX THAN ACTUALLY EXISTED. MONTAGUE ISLAND HAS NO WX RPTING. IN FACT; THE CLOSEST IS ABOUT 50 NM AWAY. RCO'S ARE UNRELIABLE. WE SHOULD HAVE GOTTEN AN UPDATE ON THE RCO AS SOON AS WE HAD ENOUGH ALT; BUT AS YOU WILL SEE; WE WERE PRETTY BUSY. WHAT WE SHOULD HAVE DONE IS TURNED AROUND RIGHT THEN; AND WORRIED ABOUT GETTING ADDITIONAL FUEL LATER; ALTHOUGH WE PROBABLY WOULD HAVE HAD TO DSND BELOW MEA IN IMC. THE ICE CONTINUED BUILDING; UNTIL WE WERE NO LONGER ABLE TO CLB; OR MAINTAIN ALT. NOW; WITH OUR SECTIONALS TO FIND THE TOPS OF MOUNTAINS WE WERE ABLE TO DSND TO 6500 FT AND FIND A HOLE WE COULD GO DOWN INTO A VALLEY AND MELT THE REST OF THE ICE OFF. WE REALLY DIDN'T KNOW WHAT OUR FUEL REMAINING WAS AT THAT POINT. WE HAD USED FULL THROTTLE MOST OF THE FLT AND WERE CARRYING ENOUGH ICE TO PROBABLY PUT US AT OR ABOVE GROSS WT. SO FUEL BURN = ? IT TURNED OUT WE HAD ABOUT 1 HR OF FUEL LEFT WHEN WE LANDED (AT 'NORMAL' CRUISE) BUT IT IS WORRISOME TO SEE BOTH GAUGES ON 'E' WHILE YOU ARE FLYING -- IMC WITH ICE; IN MOUNTAINS. I AM VERY THANKFUL WE HAD SECTIONALS WITH US AND I WILL NOT FLY IMC WITHOUT THEM.