IFR general aviation pilot experienced a 100 ft assent from assigned altitude because of turbulence;...

Narrative:

I had departed bff in VFR conditions. The automated weather was reporting a scattered layer of clouds at around 5000 ft AGL. It was my intention to climb up above the scattered layer in VFR to a cruising altitude of 9500 ft. After I realized that would be difficult; as the clouds were tending to broken rather than scattered; I called denver center and requested an IFR clearance to VFR on top. Denver center cleared me to my destination of fbl; advised me to climb and maintain 11;000; report VFR conditions; and if not in VFR conditions to maintain 11;000 ft and contact center. Upon reaching 11;000 ft I was just on top of the cloud layer and could not maintain VFR cloud separation 100 % of the time. I advised center and I remained on my IFR flight plan. For most of the flight I was clear of clouds; but every few miles I would fly through a cloud top. The turbulence in the cloud tops was light but always present when I passed through a top. Shortly after denver center handed me off to minneapolis center I flew through a cloud top and quickly gained 100 ft. Immediately thereafter minneapolis center asked me to confirm I was at 11;000'. At the time of the call I was already correcting back to 11;000' from 11;100'. I advised center that I had been blown up to 11;100' but was back at 11;000' by the time I responded. Center acknowledged my transmission and nothing further was said about the issue. There were no traffic conflicts that I was aware of and as far as I could tell there was no other IFR traffic near my position. After I landed I was speaking with an exceptionally experienced ATP who told me that the only mistake I made was admitting to center that I was off altitude momentarily by 100'. He told me I should never admit to being off altitude; that transponders/radar was not always accurate; and I should always advise center that I was on altitude. I am writing this report for two reasons. First; in the off chance that my altitude deviation was reported by mpls center I want to be protected if possible by the ASRS system as the error was inadvertent. To prevent this in the future all I can do is keep practicing my altitude holding. But I know that every once in a while I will run into turbulence that will result in a deviation even if small. But there is a second reason I am reporting this as well. My ATP friend's reaction is not unique. I have heard the comment from many pilots and I think it is a real problem. I believe that the relationship between pilots and ATC must be based on honesty and trust. I felt I was doing an excellent job maintaining altitudes through the cloud tops. I am convinced that if the flight had been my IFR check ride I would have passed with flying colors. But yes I got off altitude momentarily. I fly a light airplane; I am still learning to fly in IFR conditions; have very little actual experience (3-4 hours); and I need to fly in the clouds to improve. But how am I to get that practice if I hesitate from flying in the clouds because a slight momentary variation in altitude in turbulence might lead to a violation. I also don't want to worry constantly about being honest with ATC. I don't know what the answer is but I would think the FAA would want to encourage pilots to be totally honest about every phase of every flight.

Original NASA ASRS Text

Title: IFR general aviation pilot experienced a 100 FT assent from assigned altitude because of turbulence; reporting same to ATC; fellow pilot suggesting not to admit slight altitude variations to ATC.

Narrative: I had departed BFF in VFR conditions. The automated weather was reporting a scattered layer of clouds at around 5000 FT AGL. It was my intention to climb up above the scattered layer in VFR to a cruising altitude of 9500 FT. After I realized that would be difficult; as the clouds were tending to broken rather than scattered; I called Denver Center and requested an IFR clearance to VFR on Top. Denver Center cleared me to my destination of FBL; advised me to climb and maintain 11;000; report VFR conditions; and if not in VFR conditions to maintain 11;000 FT and contact Center. Upon reaching 11;000 FT I was just on top of the cloud layer and could not maintain VFR cloud separation 100 % of the time. I advised Center and I remained on my IFR flight plan. For most of the flight I was clear of clouds; but every few miles I would fly through a cloud top. The turbulence in the cloud tops was light but always present when I passed through a top. Shortly after Denver Center handed me off to Minneapolis Center I flew through a cloud top and quickly gained 100 FT. Immediately thereafter Minneapolis Center asked me to confirm I was at 11;000'. At the time of the call I was already correcting back to 11;000' from 11;100'. I advised Center that I had been blown up to 11;100' but was back at 11;000' by the time I responded. Center acknowledged my transmission and nothing further was said about the issue. There were no traffic conflicts that I was aware of and as far as I could tell there was no other IFR traffic near my position. After I landed I was speaking with an exceptionally experienced ATP who told me that the only mistake I made was admitting to Center that I was off altitude momentarily by 100'. He told me I should never admit to being off altitude; that transponders/radar was not always accurate; and I should always advise center that I was on altitude. I am writing this report for two reasons. First; in the off chance that my altitude deviation was reported by MPLS Center I want to be protected if possible by the ASRS system as the error was inadvertent. To prevent this in the future all I can do is keep practicing my altitude holding. But I know that every once in a while I will run into turbulence that will result in a deviation even if small. But there is a second reason I am reporting this as well. My ATP friend's reaction is not unique. I have heard the comment from many pilots and I think it is a real problem. I believe that the relationship between pilots and ATC must be based on honesty and trust. I felt I was doing an excellent job maintaining altitudes through the cloud tops. I am convinced that if the flight had been my IFR check ride I would have passed with flying colors. But yes I got off altitude momentarily. I fly a light airplane; I am still learning to fly in IFR conditions; have very little actual experience (3-4 hours); and I need to fly in the clouds to improve. But how am I to get that practice if I hesitate from flying in the clouds because a slight momentary variation in altitude in turbulence might lead to a violation. I also don't want to worry constantly about being honest with ATC. I don't know what the answer is but I would think the FAA would want to encourage pilots to be totally honest about every phase of every flight.

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.

Attributes
ACN	842413
Time
Date	200907
Local Time Of Day	1201-1800
Place
Locale Reference	ONL.VORTAC
State Reference	NE
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	Skylane 182/RG Turbo Skylane/RG
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Single Pilot
Qualification	Flight Crew Private Flight Crew Instrument
Experience	Flight Crew Last 90 Days 72.3 Flight Crew Total 336.2 Flight Crew Type 196.1
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter Weather / Turbulence

IFR general aviation pilot experienced a 100 ft assent from assigned altitude because of turbulence; reporting same to ATC; fellow pilot suggesting not to admit slight altitude variations to ATC.