Narrative:

I received an IFR clearance and read the clearance back as; cleared as filed; FL350... Read back was correct. Bzn ground had queried me as to my departure option. I advised I would depart using a similar sequence as in bzn one departure (the SID). However; I would modify it and turn to the south early as to avoid IMC and convective cloud activity on the SID. It was a departure on my own navigation. After being cleared for take off on runway 12; bzn tower changed my clearance to the SID whitehall one; and informed me that I was cleared for departure. This is where I feel the process fell apart. However; I would not know what was about to happen until after departure. I advised bzn tower that I would need a 30 second delay to re-program the GPS for the whitehall one departure after they cleared me for departure and then handed me the new routing. I read back whitehall one departure. No altitude was ever revised or assigned. I assumed to FL350 as issued before. I re-programmed the GPS and departed runway 12 on the whitehall one. After departure I made a right hand turn to heading 322 degrees; per the SID; and proceeded toward the bzn fix. I was handed to ZLC. After checking in with center through 6500 climbing FL350; they delayed a moment and then advised me no climb to 11000! I read back the clearance and re-set the altitude pre-select for 11000 and quickly adjusted my altimeter back to 30.21 from 29.92 as was originally anticipated in the non-stop climb to FL350. Shortly after ZLC advised me of the climb to 11000; they instructed me to turn left to heading 300. I read back 300 and complied with a standard-rate turn to the left. Shortly thereafter; center radioed something to the effect we need you to give us a left turn immediately to 300 (degrees). I immediately sensed their urgency by their voice reflection and tone. I was also well aware of an airline flight inbound on an approach to bzn. I assumed this inbound was why they vectored me left and needed the turn immediately. I suddenly hit the edge of solid IMC (cumulus nimbus; light rime ice; and severe turbulence; with a squeal in my radio from the static in the clouds). My aircraft's autopilot was knocked off due to the turbulence just as I was passing 10700 MSL. Suddenly center came on the radio again and urged me to turn immediately (I think direct to destination or heading 200-I can't quite recall at this point). I advised them; with voice reflection of the extreme disdain for the position they placed me in that I was in a 45 degree bank angle; severe turbulence and turning as requested by them in their last transition. At this point I was not comfortable with what was happening with a series of urgent vectors by ZLC and them demanding I perform these turns especially considering I had entered severe turbulence. I knew I was not in a good position to challenge these requirements due to several things that were unfolding. These were the inbound airline flight on approach; them giving me quick vectors in haste; which I had no time to refute and the fact that I had completed (so far) an un-expected turn of more than 30 degrees toward clouds that I wanted to avoid in the first place. At approximately 10800 MSA while in a 60 degree bank to the left; at the urgency of ZLC; my aircraft entered IMC where I hit severe turbulence. Realizing the need to make a non-standard turn (60 plus degree turn) I pulled the throttles to flight idle knowing I had just entered turbulence and that I was about to level. As I entered the clouds; I immediately began to develop ice and experienced severe turbulence. (Bzn's metar was: calm; rn; overcast 6000; temperature 13 dew point 10; altimeter 30.21) ice was; no doubt; at or very near 11000 MSL as was turbulence (rn with cumulo nimbus; convective and temperature 13 which makes std adiabatic lapse rate putting icing at or above 11000). I had no choice at this point but to advance my power for the purpose of enabling all of my anti-icing devices to work. (N1/N2must be at least 70% for these systems to work). As I advanced power; auto pilot having been knocked off; and me trying to level in convective IMC; I began a sudden climb. Realizing that advancing power increased climb; I immediately spoiled lift with speed brakes. It was at this point center advised me I was 11300; bzn altimeter 30.21. I replied by acknowledging and advised them I was correcting. I was taking such immediate action during the severe turbulence to limit my altitude that a beverage cooler as well as operating manuals and books began to float in the airplane and came to an abrupt rest in the cockpit. My visual and audio TA system was annunciating alerting me of the warning. The last I saw my altimeter was 11300 with bzn 30.21 set. I went wings level; flight idle and held all inputs until the turbulence settled to light continuous. I continued and eventually entered VMC conditions at 11000 MSL I am not sure exactly of the events or communications that happened next. I simply remember center clearing me for direct destination and handing me their number to call when I arrive at destination. I copied the number and called ZLC ATC when I arrived and spoke to a supervisor; who was reviewing radar videos and radio transmission tapes. He was not quite done reviewing the material and asked if I could call him back in one half-hour.

Related reports:

Google
 

Original NASA ASRS Text

Title: Corporate jet pilot reports encountering a thunderstorm at 11000 FT during the HIA1 departure from BZN. Reporter had been advised to turn left to avoid arriving airliner and level at 11000 FT. The turn was not fast enough to avoid a TCAS RA and the turbulence caused an altitude deviation.

Narrative: I received an IFR clearance and read the clearance back as; Cleared as filed; FL350... Read back was correct. BZN Ground had queried me as to my departure option. I advised I would depart using a similar sequence as in BZN One Departure (The SID). However; I would modify it and turn to the south early as to avoid IMC and convective cloud activity on the SID. It was a departure on my own navigation. After being cleared for take off on Runway 12; BZN Tower changed my clearance to the SID Whitehall ONE; and informed me that I was cleared for departure. This is where I feel the process fell apart. However; I would not know what was about to happen until after departure. I advised BZN Tower that I would need a 30 second delay to re-program the GPS for the Whitehall One Departure after they cleared me for departure and then handed me the new routing. I read back Whitehall One departure. NO ALTITUDE was ever revised or assigned. I assumed to FL350 as issued before. I re-programmed the GPS and departed Runway 12 on the Whitehall One. After departure I made a right hand turn to HDG 322 degrees; per the SID; and proceeded toward the BZN fix. I was handed to ZLC. After checking in with Center through 6500 climbing FL350; they delayed a moment and then advised me NO climb to 11000! I read back the clearance and re-set the altitude pre-select for 11000 and quickly adjusted my altimeter back to 30.21 from 29.92 as was originally anticipated in the non-stop climb to FL350. Shortly after ZLC advised me of the climb to 11000; they instructed me to turn left to HDG 300. I read back 300 and complied with a standard-rate turn to the left. Shortly thereafter; Center radioed something to the effect we need you to give us a left turn immediately to 300 (degrees). I immediately sensed their urgency by their voice reflection and tone. I was also well aware of an airline flight inbound on an approach to BZN. I assumed this inbound was why they vectored me left and needed the turn immediately. I suddenly hit the edge of solid IMC (Cumulus nimbus; light rime ice; and severe turbulence; with a squeal in my radio from the static in the clouds). My aircraft's autopilot was knocked off due to the turbulence just as I was passing 10700 MSL. Suddenly Center came on the radio again and urged me to turn immediately (I think direct to destination or HDG 200-I can't quite recall at this point). I advised them; with voice reflection of the extreme disdain for the position they placed me in that I was in a 45 degree bank angle; severe turbulence and turning as requested by them in their last transition. At this point I was not comfortable with what was happening with a series of urgent vectors by ZLC and them demanding I perform these turns especially considering I had entered severe turbulence. I knew I was not in a good position to challenge these requirements due to several things that were unfolding. These were the inbound airline flight on approach; them giving me quick vectors in haste; which I had no time to refute and the fact that I had completed (so far) an un-expected turn of more than 30 degrees toward clouds that I wanted to avoid in the first place. At approximately 10800 MSA while in a 60 degree bank to the left; at the urgency of ZLC; my aircraft entered IMC where I hit severe turbulence. Realizing the need to make a non-standard turn (60 plus degree turn) I pulled the throttles to flight idle knowing I had just entered turbulence and that I was about to level. As I entered the clouds; I immediately began to develop ice and experienced severe turbulence. (BZN's METAR was: Calm; RN; overcast 6000; temperature 13 dew point 10; altimeter 30.21) Ice was; no doubt; at or very near 11000 MSL as was turbulence (RN with cumulo nimbus; convective and temperature 13 which makes std adiabatic lapse rate putting icing at or above 11000). I had no choice at this point but to advance my power for the purpose of enabling all of my anti-icing devices to work. (N1/N2must be at least 70% for these systems to work). As I advanced power; auto pilot having been knocked off; and me trying to level in convective IMC; I began a sudden climb. Realizing that advancing power increased climb; I immediately spoiled lift with speed brakes. It was at this point Center advised me I was 11300; BZN altimeter 30.21. I replied by acknowledging and advised them I was correcting. I was taking such immediate action during the severe turbulence to limit my altitude that a beverage cooler as well as operating manuals and books began to float in the airplane and came to an abrupt rest in the cockpit. My visual and audio TA system was annunciating alerting me of the warning. The last I saw my altimeter was 11300 with BZN 30.21 set. I went wings level; flight idle and held all inputs until the turbulence settled to light continuous. I continued and eventually entered VMC conditions at 11000 MSL I am not sure exactly of the events or communications that happened next. I simply remember Center clearing me for direct destination and handing me their number to call when I arrive at destination. I copied the number and called ZLC ATC when I arrived and spoke to a supervisor; who was reviewing radar videos and radio transmission tapes. He was not quite done reviewing the material and asked if I could call him back in one half-hour.

Data retrieved from NASA's ASRS site as of April 2012 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.