In-flight icing. Unable to maintain altitude.

Attributes
ACN	319433
Time
Date	199510
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : rbl
State Reference	CO
Altitude	msl bound lower : 14000 msl bound upper : 18000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zdv
Operator	common carrier : air taxi
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 135
Flight Phase	cruise other
Route In Use	enroute airway : zdv enroute other
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 110 flight time total : 7000 flight time type : 2000
ASRS Report	319433
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : exited adverse environment
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Level at 17000 ft wbound (low altitude setting) advised ATC I was picking up severe ice and needed FL190. ATC advised he would let me know. After several attempts (3 mins) I informed the frequency 128.65 that I was climbing to FL190. By this time the airspeed had deteriorated from 195 KIAS, to 160 KIAS (the minimum recommended IAS for climb in ice). I attempted a step climb to FL190, however, I could get to only FL180. (Still no response from ATC.) it became obvious I would not be able to maintain FL180, so I requested 16000 ft, no response. I initiated a descent to 16000 ft. After again informing the frequency 128.65 on my way down I got hold of ATC and he cleared me to 16000 ft, informing me there was some confusion on who was taking which sector (controllers) during their am shift change. Prior to reaching red table I informed ATC unable to maintain 16000 ft requested 14000 ft. ATC advised the MEA did not allow below 16000 ft for a few more mins. I was unable to keep 16000 ft, and allowed the aircraft to drift to 15000 ft. I then received a clearance to 14000 ft, then became VFR. All of the aircraft anti-ice and deice were operating correctly. I attribute the problem to: ATC was focused on their problems in house, I did not take emergency action fast enough after it became clear ATC was not aware of my problems, aircraft performance was affected by airframe ice, belly and cup of wing.

Original NASA ASRS Text

Title: INFLT ICING. UNABLE TO MAINTAIN ALT.

Narrative: LEVEL AT 17000 FT WBOUND (LOW ALT SETTING) ADVISED ATC I WAS PICKING UP SEVERE ICE AND NEEDED FL190. ATC ADVISED HE WOULD LET ME KNOW. AFTER SEVERAL ATTEMPTS (3 MINS) I INFORMED THE FREQ 128.65 THAT I WAS CLBING TO FL190. BY THIS TIME THE AIRSPD HAD DETERIORATED FROM 195 KIAS, TO 160 KIAS (THE MINIMUM RECOMMENDED IAS FOR CLB IN ICE). I ATTEMPTED A STEP CLB TO FL190, HOWEVER, I COULD GET TO ONLY FL180. (STILL NO RESPONSE FROM ATC.) IT BECAME OBVIOUS I WOULD NOT BE ABLE TO MAINTAIN FL180, SO I REQUESTED 16000 FT, NO RESPONSE. I INITIATED A DSCNT TO 16000 FT. AFTER AGAIN INFORMING THE FREQ 128.65 ON MY WAY DOWN I GOT HOLD OF ATC AND HE CLRED ME TO 16000 FT, INFORMING ME THERE WAS SOME CONFUSION ON WHO WAS TAKING WHICH SECTOR (CTLRS) DURING THEIR AM SHIFT CHANGE. PRIOR TO REACHING RED TABLE I INFORMED ATC UNABLE TO MAINTAIN 16000 FT REQUESTED 14000 FT. ATC ADVISED THE MEA DID NOT ALLOW BELOW 16000 FT FOR A FEW MORE MINS. I WAS UNABLE TO KEEP 16000 FT, AND ALLOWED THE ACFT TO DRIFT TO 15000 FT. I THEN RECEIVED A CLRNC TO 14000 FT, THEN BECAME VFR. ALL OF THE ACFT ANTI-ICE AND DEICE WERE OPERATING CORRECTLY. I ATTRIBUTE THE PROB TO: ATC WAS FOCUSED ON THEIR PROBS IN HOUSE, I DID NOT TAKE EMER ACTION FAST ENOUGH AFTER IT BECAME CLR ATC WAS NOT AWARE OF MY PROBS, ACFT PERFORMANCE WAS AFFECTED BY AIRFRAME ICE, BELLY AND CUP OF WING.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.