37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Attributes | |
ACN | 1414100 |
Time | |
Date | 201701 |
Local Time Of Day | 0601-1200 |
Place | |
Locale Reference | ZZZ.Airport |
State Reference | US |
Environment | |
Flight Conditions | IMC |
Light | Night |
Aircraft 1 | |
Make Model Name | PA-31 Navajo/Chieftan/Mojave/T1040 |
Operating Under FAR Part | Part 135 |
Flight Phase | Cruise |
Flight Plan | IFR |
Person 1 | |
Function | Captain Pilot Flying |
Qualification | Flight Crew Air Transport Pilot (ATP) |
Events | |
Anomaly | Deviation - Procedural Clearance Deviation - Track / Heading All Types Inflight Event / Encounter Weather / Turbulence |
Narrative:
I [advised ATC of the situation] due to severe icing while in cruise to my destination airport. I was level at 7;000 feet when I first started building ice and requested a lower altitude of 6;000 feet. A few minutes after leveling off at 6;000 feet I noticed my airspeed continuously dropping and was no longer within range of radio communication with ATC to request a lower altitude. At which point I started relaying through a company pilot. I requested a different altitude and heading to turn south of the mountainous terrain I was flying over. After turning south I was unable to reach ATC and was not receiving the relay clearly from company aircraft; this was when I squawked 7700 and began to descend to VMC conditions. I turned south for two reasons; first I know the terrain is lower to the south of the mountains; secondly ZZZ was broadcasting VFR conditions and I knew that I would be able to shed the ice if I was able to get lower. At this point I was barely able to hold 120 knots and was not able to shed the ice. [Company aircraft] relayed to me that I had been cleared for the approach; and once I was able to clearly hear them I put in my old squawk code and proceeded. At this point my sole focus was on maintaining airspeed and altitude as I was able. I descended to 2500 feet and was still in severe icing and now moderate turbulence; at which point my stall horn chirped a couple times. After turning inbound and descending to 1700 feet the ice shed off. Once level at 1700 feet and in VMC conditions with the runway in sight I could confirm that the ice had shed off of my wings and I was able to maintain 140 knots and greater. At which point I canceled IFR and squawked 1200 to continue to [original destination]. The ceiling was reported at 2600 feet; there was no way I was going to climb back into the clouds. I maintained 1;500 feet until I was certain that I could maintain altitude and airspeed before climbing back up to 2;500 feet. I did this for three reasons. First; I could see my surrounds and knew I was in no danger of hitting anything; secondly I didn't want to start climbing until I was sure the aircraft was clear of ice before getting close to another layer; thirdly; the runway was reported as hazardous due to icing. After safely landing I called ATC to explain what happened; even though I was not requested to. Their only concern was why I continued from [my alternate to my original destination]. After explaining; they agreed with me and we were in agreement that I did the safest option for the circumstances I had. Throughout this whole ordeal there were times when I was unable to hold altitudes without drastically losing airspeed and would have to give up altitude to gain back airspeed; plus I was not in contact with ATC and was being relayed through company aircraft. So I am not sure if I was in violation of anything at the time of the emergency; but firmly believe I responded to the situation with the best of my ability.
Original NASA ASRS Text
Title: PA31 pilot reported having difficulty maintaining altitude and airspeed in icing conditions.
Narrative: I [advised ATC of the situation] due to severe icing while in cruise to my destination airport. I was level at 7;000 feet when I first started building ice and requested a lower altitude of 6;000 feet. A few minutes after leveling off at 6;000 feet I noticed my airspeed continuously dropping and was no longer within range of radio communication with ATC to request a lower altitude. At which point I started relaying through a company pilot. I requested a different altitude and heading to turn south of the mountainous terrain I was flying over. After turning south I was unable to reach ATC and was not receiving the relay clearly from company aircraft; this was when I squawked 7700 and began to descend to VMC conditions. I turned south for two reasons; first I know the terrain is lower to the south of the mountains; secondly ZZZ was broadcasting VFR conditions and I knew that I would be able to shed the ice if I was able to get lower. At this point I was barely able to hold 120 knots and was not able to shed the ice. [Company aircraft] relayed to me that I had been cleared for the approach; and once I was able to clearly hear them I put in my old squawk code and proceeded. At this point my sole focus was on maintaining airspeed and altitude as I was able. I descended to 2500 feet and was still in severe icing and now moderate turbulence; at which point my stall horn chirped a couple times. After turning inbound and descending to 1700 feet the ice shed off. Once level at 1700 feet and in VMC conditions with the runway in sight I could confirm that the ice had shed off of my wings and I was able to maintain 140 knots and greater. At which point I canceled IFR and squawked 1200 to continue to [original destination]. The ceiling was reported at 2600 feet; there was no way I was going to climb back into the clouds. I maintained 1;500 feet until I was certain that I could maintain altitude and airspeed before climbing back up to 2;500 feet. I did this for three reasons. First; I could see my surrounds and knew I was in no danger of hitting anything; secondly I didn't want to start climbing until I was sure the aircraft was clear of ice before getting close to another layer; thirdly; the runway was reported as hazardous due to icing. After safely landing I called ATC to explain what happened; even though I was not requested to. Their only concern was why I continued from [my alternate to my original destination]. After explaining; they agreed with me and we were in agreement that I did the safest option for the circumstances I had. Throughout this whole ordeal there were times when I was unable to hold altitudes without drastically losing airspeed and would have to give up altitude to gain back airspeed; plus I was not in contact with ATC and was being relayed through company aircraft. So I am not sure if I was in violation of anything at the time of the emergency; but firmly believe I responded to the situation with the best of my ability.
Data retrieved from NASA's ASRS site 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.