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An air carrier light transport departed its assigned altitude because of aircraft icing. An emergency had been declared.
| Attributes | |
| ACN | 228356 |
| Time | |
| Date | 199212 |
| Day | Sun |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : rbv |
| State Reference | NJ |
| Altitude | msl bound lower : 7000 msl bound upper : 14000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Night |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | Light Transport, Low Wing, 2 Turboprop Eng |
| Flight Phase | cruise other descent other other |
| Route In Use | enroute airway : zny |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 50 flight time total : 9000 flight time type : 200 |
| ASRS Report | 228356 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude inflight encounter : weather other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : took evasive action flight crew : exited adverse environment flight crew : declared emergency |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
Narrative:
Level at 14000 ft MSL, IMC, moderate rime ice en route jfk- mdt. Experienced moderate to severe flight control/airframe vibration. Propeller, engine heat, and elevator horn heat was on. Activated boots and 1/2 inch of ice blew off leading edges. Vibration increased. Captain advised ATC of problem and requested a lower altitude to escape icing conditions. Request was denied. Captain then advised ATC we were leaving 14000 ft for lower due to severe flight control vibration. I started down from 14000 ft broke out of clouds at 7000 ft MSL. Squawk was 7700. Vibration ceased and we continued to destination without further incident. During post-flight inspection, 1/2 inch of ice was observed on right elevator horn, which is supposed to be heated. Cockpit indications were normal. We were VMC and out of icing conditions from rbv to mdt at 6000 ft MSL, a distance of 120 mi. Who knows how much of the ice on the elevator horn sublimated off during that period.
Original NASA ASRS Text
Title: AN ACR LTT DEPARTED ITS ASSIGNED ALT BECAUSE OF ACFT ICING. AN EMER HAD BEEN DECLARED.
Narrative: LEVEL AT 14000 FT MSL, IMC, MODERATE RIME ICE ENRTE JFK- MDT. EXPERIENCED MODERATE TO SEVERE FLT CTL/AIRFRAME VIBRATION. PROP, ENG HEAT, AND ELEVATOR HORN HEAT WAS ON. ACTIVATED BOOTS AND 1/2 INCH OF ICE BLEW OFF LEADING EDGES. VIBRATION INCREASED. CAPT ADVISED ATC OF PROB AND REQUESTED A LOWER ALT TO ESCAPE ICING CONDITIONS. REQUEST WAS DENIED. CAPT THEN ADVISED ATC WE WERE LEAVING 14000 FT FOR LOWER DUE TO SEVERE FLT CTL VIBRATION. I STARTED DOWN FROM 14000 FT BROKE OUT OF CLOUDS AT 7000 FT MSL. SQUAWK WAS 7700. VIBRATION CEASED AND WE CONTINUED TO DEST WITHOUT FURTHER INCIDENT. DURING POST-FLT INSPECTION, 1/2 INCH OF ICE WAS OBSERVED ON R ELEVATOR HORN, WHICH IS SUPPOSED TO BE HEATED. COCKPIT INDICATIONS WERE NORMAL. WE WERE VMC AND OUT OF ICING CONDITIONS FROM RBV TO MDT AT 6000 FT MSL, A DISTANCE OF 120 MI. WHO KNOWS HOW MUCH OF THE ICE ON THE ELEVATOR HORN SUBLIMATED OFF DURING THAT PERIOD.
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.