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BeechBoy · February 21st, 2008, 12:56

First off, to answer someone's question about DO-Jet ice protection, it's boots only on the wings and tail.

This is going to be a long post but I think it's worth reading to the end because it shows how management can be 100% convinced that they are right when they are 100% WRONG!!

After cancelling this flight I basically got reamed out by the Chief Pilot. His argument was that the warning in the AFM in no way constituted a limitation against taking off into light freezing rain. The arguments of Skyway management (Director of Safety, Director of Ops, Head of Training, and Chief Pilot) are as follows:

1. Since the warning doesn't specifically mention "light" freezing rain (only freezing rain / freezing drizzle) it may be implied that the AFM was referring to moderate freezing rain & moderate freezing drizzle. (I agree that this is the convention in weather reports but I'm not convinced that the AFM makes this distinction).

2. Since the warning states that freezing rain/freezing drizzle MAY (not WILL) cause control or performance problems it is OK to take off. If you do encounter severe icing then you can use the procedure for exiting severe icing outlined in the AFM. (My opinion: if the AFM says that if you do something you MAY die that's enough for me. I ain't doin' it!).

3. Since we have a holdover time for light freezing rain in our FAA approved company manual it may be implied that it is OK to take off into these conditions. (My opinion: after you takeoff, type 4 protection is gone and you're still in uncertified icing conditions. Also, the FSDO wants to remove the holdover time for flight into light freezing rain because they think it gives a false sense of security that it's OK to fly into these conditions).

4. The NASA icing research on SLD (supercooled large drops) was done on a Twin Otter. We fly a 328 which has a different wing. Therefore, conclusions reached on the Otter cannot be applied to the DO-Jet.

I contacted Dornier 328 Support Services in Germany. Their response: "Takeoff into freezing rain, even light freezing rain, is not permitted". (Skyway doesn't accept this answer: they don't think Support Services has the authority to interpret the warning).

Next I contacted, Bill Rieke, a NASA research pilot who was involved in NASA's icing research for 15+ years. He was also the co-chairman of the first NASA/FAA International Tailplane Icing Conference. In summary, when it comes to aircraft icing this guy is God. His verdict was that even light freezing drizzle can be hazardous to aircraft. Aircraft are certified for flight into "cloud sized droplets" (40-50 microns). These droplets are so small that they will do one of two things if they encounter an aircraft. They will either strike the leading edge of the wing (which is protected) or they will follow the streamlines around the wing without impacting it. Freezing drizzle is 100-150 microns (freezing rain can be 1000 microns or larger). When droplets get larger than 50 microns they are classified as SLD. Droplets this large have enough mass that they will cross the streamlines of the wing and will impact aft of the boots. This is a virtual certainty. When taking off into freezing rain or freezing drizzle (even "light" stuff) you WILL get ice aft of the boots or heated leading edge, it's just a matter of how much. His summary of my actions were "you did the right thing". (Sporty's offers his 40-page book "In-Flight Icing" very inexpensively and it's a very good reference).

I'm sure that there are pilots who have flown in freezing rain and have gotten away with it but I don't care. (I'm not passing judgement. If your AFM says that you're safe for light freezing rain that's one thing but ours does not). I'm 95% sure that I could have taken off and gotten out of the icing before things got out of hand but that's not how I play the game. If I'm safely on the ground I'm not going to take off into potentially hazardous conditions that have a clear warning in the AFM just because the odds are in my favor. Remember the DC-10 that got "microbursted" in Dallas? Do you think that was his first time playing with T-storms? Same thing with the A-340 that ran off the runway in Toronto. My philosophy is that, to the best of my ability, I'm going to do what's right and what's safe - not what others do or have done. Endeth the sermon.

February 21st, 2008, 12:56	#8
BeechBoy Junior Member Join Date: Jan 2007 Location: Milwaukee, Wi Posts: 66	Re: Takeoff into light freezing rain First off, to answer someone's question about DO-Jet ice protection, it's boots only on the wings and tail. This is going to be a long post but I think it's worth reading to the end because it shows how management can be 100% convinced that they are right when they are 100% WRONG!! After cancelling this flight I basically got reamed out by the Chief Pilot. His argument was that the warning in the AFM in no way constituted a limitation against taking off into light freezing rain. The arguments of Skyway management (Director of Safety, Director of Ops, Head of Training, and Chief Pilot) are as follows: 1. Since the warning doesn't specifically mention "light" freezing rain (only freezing rain / freezing drizzle) it may be implied that the AFM was referring to moderate freezing rain & moderate freezing drizzle. (I agree that this is the convention in weather reports but I'm not convinced that the AFM makes this distinction). 2. Since the warning states that freezing rain/freezing drizzle MAY (not WILL) cause control or performance problems it is OK to take off. If you do encounter severe icing then you can use the procedure for exiting severe icing outlined in the AFM. (My opinion: if the AFM says that if you do something you MAY die that's enough for me. I ain't doin' it!). 3. Since we have a holdover time for light freezing rain in our FAA approved company manual it may be implied that it is OK to take off into these conditions. (My opinion: after you takeoff, type 4 protection is gone and you're still in uncertified icing conditions. Also, the FSDO wants to remove the holdover time for flight into light freezing rain because they think it gives a false sense of security that it's OK to fly into these conditions). 4. The NASA icing research on SLD (supercooled large drops) was done on a Twin Otter. We fly a 328 which has a different wing. Therefore, conclusions reached on the Otter cannot be applied to the DO-Jet. I contacted Dornier 328 Support Services in Germany. Their response: "Takeoff into freezing rain, even light freezing rain, is not permitted". (Skyway doesn't accept this answer: they don't think Support Services has the authority to interpret the warning). Next I contacted, Bill Rieke, a NASA research pilot who was involved in NASA's icing research for 15+ years. He was also the co-chairman of the first NASA/FAA International Tailplane Icing Conference. In summary, when it comes to aircraft icing this guy is God. His verdict was that even light freezing drizzle can be hazardous to aircraft. Aircraft are certified for flight into "cloud sized droplets" (40-50 microns). These droplets are so small that they will do one of two things if they encounter an aircraft. They will either strike the leading edge of the wing (which is protected) or they will follow the streamlines around the wing without impacting it. Freezing drizzle is 100-150 microns (freezing rain can be 1000 microns or larger). When droplets get larger than 50 microns they are classified as SLD. Droplets this large have enough mass that they will cross the streamlines of the wing and will impact aft of the boots. This is a virtual certainty. When taking off into freezing rain or freezing drizzle (even "light" stuff) you WILL get ice aft of the boots or heated leading edge, it's just a matter of how much. His summary of my actions were "you did the right thing". (Sporty's offers his 40-page book "In-Flight Icing" very inexpensively and it's a very good reference). I'm sure that there are pilots who have flown in freezing rain and have gotten away with it but I don't care. (I'm not passing judgement. If your AFM says that you're safe for light freezing rain that's one thing but ours does not). I'm 95% sure that I could have taken off and gotten out of the icing before things got out of hand but that's not how I play the game. If I'm safely on the ground I'm not going to take off into potentially hazardous conditions that have a clear warning in the AFM just because the odds are in my favor. Remember the DC-10 that got "microbursted" in Dallas? Do you think that was his first time playing with T-storms? Same thing with the A-340 that ran off the runway in Toronto. My philosophy is that, to the best of my ability, I'm going to do what's right and what's safe - not what others do or have done. Endeth the sermon.