Instrument rated private pilots on IFR practice flight deviate from clearance at will due to WX and ...

Narrative:

The incident below describes to the best of knowledge an exchange between ATC and the pilots during a training IFR flight. No near misses occurred but ATC was annoyed at pilot decisions during adverse WX conditions in partial IMC. Standard WX briefing included an airmet for turbulence; icing and obscuration. IFR clearance was via LVK1; V244 eca direct; maintain 4000 ft expect 5000 ft in 10 mins; departure frequency 125.35. ATIS was 280 at 6; visibility 10; ceiling 3500 ft scattered; 4700 ft broken; altimeter 30.12. FSS reported possible icing below FL180; airmet for turbulence. Reached altam intersection (LVK1 departure) just below cloud layer at 4000 ft. On turnout to eca large dark cumulus cloud in build stage tops to +7000 ft in direct path. OAT 36 degrees F high probability of icing in cloud. ATC was very busy on radios with other traffic; probably to do with vectoring around WX close to the livermore hills. To avoid cloud and heavy possibility of icing turned southeast towards tracy airport. Temperature 35 degrees F. Tracy could serve as an alternate airport to land if necessary and is the missed for lvk. Reached ATC 2-3 mins after turn at 4000 ft and informed ATC of change for safety and the aircraft is not permitted into icing conditions. ATC was very annoyed at this late notification; but we did contact them at first opportunity. ATC cleared us to eca for practice ILS approachs once we cleared danger. ATC asked us if we wanted to climb to 5000 ft or stay at 4000 ft. We informed ATC we would climb to 5000 ft. We thought we could clear another small cell at 5000 ft. Climbed to 5100 ft in moderate turbulence. Altitude in autoplt +/-150 ft due to turbulence. On way to eca it became apparent we could not clear the cloud so we started a descent to 4000 ft. We believe ATC was busy and we informed them as soon as the airplane was out of turbulence and ATC was not busy. This took place at 4300-4500 ft AGL. ATC informed us that we were flying at 3500 ft. We had 2 pilots and 4 instruments capable of providing altitude and all said we never descended below 4000 ft; our initial altitude. The controller was very agitated with us and we believe he had similar experience with other pilots and his heavy workload. We went on to fly 4 perfect ILS and VOR approachs without incident in VFR conditions. ATC told us to land and call the center for pilot deviation and we complied. We believe the PIC has the ability to change ATC instructions if it is believed the safety of the flight is in danger; which we did. The ATC controller was unaware of the flight conditions in that particular area of flight and was in overload conditions with other flts. We went on to contact 4 perfect approachs with another controller. We contacted ATC when we were capable and when we would not step over other xmissions. ATC should have decreased his workload or asked for assistance during this situation. The controller was aggravated during the flight and another pilot commented that he (ATC) was doing fine. Apparently due to another flight situation.

Original NASA ASRS Text

Title: INSTRUMENT RATED PRIVATE PLTS ON IFR PRACTICE FLT DEVIATE FROM CLRNC AT WILL DUE TO WX AND TURBULENCE CONCERNS. ATC TAKES ISSUE WITH THEIR FAILURE TO OBTAIN CLRNCS PRIOR TO DEVIATIONS.

Narrative: THE INCIDENT BELOW DESCRIBES TO THE BEST OF KNOWLEDGE AN EXCHANGE BTWN ATC AND THE PLTS DURING A TRAINING IFR FLT. NO NEAR MISSES OCCURRED BUT ATC WAS ANNOYED AT PLT DECISIONS DURING ADVERSE WX CONDITIONS IN PARTIAL IMC. STANDARD WX BRIEFING INCLUDED AN AIRMET FOR TURB; ICING AND OBSCURATION. IFR CLRNC WAS VIA LVK1; V244 ECA DIRECT; MAINTAIN 4000 FT EXPECT 5000 FT IN 10 MINS; DEP FREQ 125.35. ATIS WAS 280 AT 6; VISIBILITY 10; CEILING 3500 FT SCATTERED; 4700 FT BROKEN; ALTIMETER 30.12. FSS RPTED POSSIBLE ICING BELOW FL180; AIRMET FOR TURB. REACHED ALTAM INTXN (LVK1 DEP) JUST BELOW CLOUD LAYER AT 4000 FT. ON TURNOUT TO ECA LARGE DARK CUMULUS CLOUD IN BUILD STAGE TOPS TO +7000 FT IN DIRECT PATH. OAT 36 DEGS F HIGH PROBABILITY OF ICING IN CLOUD. ATC WAS VERY BUSY ON RADIOS WITH OTHER TFC; PROBABLY TO DO WITH VECTORING AROUND WX CLOSE TO THE LIVERMORE HILLS. TO AVOID CLOUD AND HVY POSSIBILITY OF ICING TURNED SE TOWARDS TRACY ARPT. TEMP 35 DEGS F. TRACY COULD SERVE AS AN ALTERNATE ARPT TO LAND IF NECESSARY AND IS THE MISSED FOR LVK. REACHED ATC 2-3 MINS AFTER TURN AT 4000 FT AND INFORMED ATC OF CHANGE FOR SAFETY AND THE ACFT IS NOT PERMITTED INTO ICING CONDITIONS. ATC WAS VERY ANNOYED AT THIS LATE NOTIFICATION; BUT WE DID CONTACT THEM AT FIRST OPPORTUNITY. ATC CLRED US TO ECA FOR PRACTICE ILS APCHS ONCE WE CLRED DANGER. ATC ASKED US IF WE WANTED TO CLB TO 5000 FT OR STAY AT 4000 FT. WE INFORMED ATC WE WOULD CLB TO 5000 FT. WE THOUGHT WE COULD CLR ANOTHER SMALL CELL AT 5000 FT. CLBED TO 5100 FT IN MODERATE TURB. ALT IN AUTOPLT +/-150 FT DUE TO TURB. ON WAY TO ECA IT BECAME APPARENT WE COULD NOT CLR THE CLOUD SO WE STARTED A DSCNT TO 4000 FT. WE BELIEVE ATC WAS BUSY AND WE INFORMED THEM AS SOON AS THE AIRPLANE WAS OUT OF TURB AND ATC WAS NOT BUSY. THIS TOOK PLACE AT 4300-4500 FT AGL. ATC INFORMED US THAT WE WERE FLYING AT 3500 FT. WE HAD 2 PLTS AND 4 INSTS CAPABLE OF PROVIDING ALT AND ALL SAID WE NEVER DSNDED BELOW 4000 FT; OUR INITIAL ALT. THE CTLR WAS VERY AGITATED WITH US AND WE BELIEVE HE HAD SIMILAR EXPERIENCE WITH OTHER PLTS AND HIS HVY WORKLOAD. WE WENT ON TO FLY 4 PERFECT ILS AND VOR APCHS WITHOUT INCIDENT IN VFR CONDITIONS. ATC TOLD US TO LAND AND CALL THE CTR FOR PLTDEV AND WE COMPLIED. WE BELIEVE THE PIC HAS THE ABILITY TO CHANGE ATC INSTRUCTIONS IF IT IS BELIEVED THE SAFETY OF THE FLT IS IN DANGER; WHICH WE DID. THE ATC CTLR WAS UNAWARE OF THE FLT CONDITIONS IN THAT PARTICULAR AREA OF FLT AND WAS IN OVERLOAD CONDITIONS WITH OTHER FLTS. WE WENT ON TO CONTACT 4 PERFECT APCHS WITH ANOTHER CTLR. WE CONTACTED ATC WHEN WE WERE CAPABLE AND WHEN WE WOULD NOT STEP OVER OTHER XMISSIONS. ATC SHOULD HAVE DECREASED HIS WORKLOAD OR ASKED FOR ASSISTANCE DURING THIS SIT. THE CTLR WAS AGGRAVATED DURING THE FLT AND ANOTHER PLT COMMENTED THAT HE (ATC) WAS DOING FINE. APPARENTLY DUE TO ANOTHER FLT SIT.

Data retrieved from NASA's ASRS site as of January 2009 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	730304
Time
Date	200702
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : nct.tracon
State Reference	CA
Altitude	agl single value : 4500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : nct.tracon
Operator	general aviation : personal
Make Model Name	SR22
Operating Under FAR Part	Part 91
Flight Phase	cruise : level descent : approach
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 40 flight time total : 650 flight time type : 650
ASRS Report	730304
Person 2
Affiliation	government : faa
Function	controller : approach
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter : weather non adherence : clearance non adherence : published procedure other spatial deviation
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	faa : assigned or threatened penalties other
Supplementary
Problem Areas	Flight Crew Human Performance Environmental Factor ATC Human Performance Weather
Primary Problem	Ambiguous
Air Traffic Incident	Pilot Deviation

Instrument rated private pilots on IFR practice flight deviate from clearance at will due to WX and turbulence concerns. ATC takes issue with their failure to obtain clrncs prior to deviations.