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Pilot of small transport encountered more icing than aircraft could maintain altitude with, started descent and finally obtained revised clearance from center.
| Attributes | |
| ACN | 186235 |
| Time | |
| Date | 199108 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : pmm |
| State Reference | MI |
| Altitude | msl bound lower : 15500 msl bound upper : 16000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zau |
| Operator | common carrier : air taxi |
| Make Model Name | Small Transport, Low Wing, 2 Turboprop Eng |
| Flight Phase | cruise other descent other |
| Route In Use | enroute airway : zau |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air taxi |
| Function | flight crew : single pilot |
| Qualification | pilot : commercial pilot : instrument |
| Experience | flight time last 90 days : 187 flight time total : 5800 flight time type : 280 |
| ASRS Report | 186235 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Events | |
| Anomaly | aircraft equipment problem : less severe inflight encounter : weather non adherence : clearance other anomaly |
| Independent Detector | other other : unspecified cockpit |
| Resolutory Action | flight crew : exited adverse environment flight crew : declared emergency |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
Aircraft was cruising at 16000 ft encountering light, to trace icing. All deice and anti-ice system were operating normally. Aircraft then entered area of moderate icing. I requested a lower altitude. Center advised unable due to traffic. Shortly after this aircraft entered area of severe icing. Due to frequency congestion, I was unable to advise center of the problem. Aircraft picked up a large load of ice, deicing equipment was unable to control the icing. Aircraft was soon unable to maintain altitude and started to descend. Aircraft had descended about 500 ft when center was advised as to the descent. They advised descent unable due to traffic. I replied we were coming down. The center then asked if we wanted to declare an emergency. I replied negative, as aircraft was in control and had exited severe icing at this time. Center then assigned us a heading and clearance to 10000 ft. Descending out of 12000 ft all ice was shed and center advised. Any traffic conflict is unknown to me. No other aircraft was advised to traffic conflict or asked to deviate, that I heard. I had been unable to advise center of problem, a lot of aircraft were trying to change altitudes, but no reports as to icing were given. Forecasts had only called for a chance of light icing. In retrospect, I should have insisted on descending sooner and have anticipated this type of situation sooner. Contributing factors I feel were the frequency congestion and ATC procedures putting all the traffic over 1 fix, leaving little room for possible deviations.
Original NASA ASRS Text
Title: PLT OF SMT ENCOUNTERED MORE ICING THAN ACFT COULD MAINTAIN ALT WITH, STARTED DSCNT AND FINALLY OBTAINED REVISED CLRNC FROM CENTER.
Narrative: ACFT WAS CRUISING AT 16000 FT ENCOUNTERING LIGHT, TO TRACE ICING. ALL DEICE AND ANTI-ICE SYS WERE OPERATING NORMALLY. ACFT THEN ENTERED AREA OF MODERATE ICING. I REQUESTED A LOWER ALT. CENTER ADVISED UNABLE DUE TO TFC. SHORTLY AFTER THIS ACFT ENTERED AREA OF SEVERE ICING. DUE TO FREQ CONGESTION, I WAS UNABLE TO ADVISE CENTER OF THE PROBLEM. ACFT PICKED UP A LARGE LOAD OF ICE, DEICING EQUIP WAS UNABLE TO CTL THE ICING. ACFT WAS SOON UNABLE TO MAINTAIN ALT AND STARTED TO DSND. ACFT HAD DSNDED ABOUT 500 FT WHEN CENTER WAS ADVISED AS TO THE DSCNT. THEY ADVISED DSCNT UNABLE DUE TO TFC. I REPLIED WE WERE COMING DOWN. THE CENTER THEN ASKED IF WE WANTED TO DECLARE AN EMER. I REPLIED NEGATIVE, AS ACFT WAS IN CTL AND HAD EXITED SEVERE ICING AT THIS TIME. CENTER THEN ASSIGNED US A HDG AND CLRNC TO 10000 FT. DSNDING OUT OF 12000 FT ALL ICE WAS SHED AND CENTER ADVISED. ANY TFC CONFLICT IS UNKNOWN TO ME. NO OTHER ACFT WAS ADVISED TO TFC CONFLICT OR ASKED TO DEVIATE, THAT I HEARD. I HAD BEEN UNABLE TO ADVISE CENTER OF PROBLEM, A LOT OF ACFT WERE TRYING TO CHANGE ALTS, BUT NO RPTS AS TO ICING WERE GIVEN. FORECASTS HAD ONLY CALLED FOR A CHANCE OF LIGHT ICING. IN RETROSPECT, I SHOULD HAVE INSISTED ON DSNDING SOONER AND HAVE ANTICIPATED THIS TYPE OF SITUATION SOONER. CONTRIBUTING FACTORS I FEEL WERE THE FREQ CONGESTION AND ATC PROCS PUTTING ALL THE TFC OVER 1 FIX, LEAVING LITTLE ROOM FOR POSSIBLE DEVS.
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.