Small aircraft on IFR training flight encounters ice at 12000 ft, loses static instruments and reque...

Attributes
ACN	361756
Time
Date	199702
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : rno
State Reference	NV
Altitude	msl bound lower : 10400 msl bound upper : 11000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	general aviation : instructional
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other other
Route In Use	enroute airway : zoa
Flight Plan	IFR
Person 1
Affiliation	Other
Function	instruction : instructor oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : cfi
Experience	flight time last 90 days : 200 flight time total : 540 flight time type : 60
ASRS Report	361756
Person 2
Affiliation	Other
Function	instruction : trainee
Qualification	pilot : private
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot inflight encounter : weather inflight encounter other non adherence : clearance
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued new clearance flight crew : exited adverse environment flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

During long IFR cross country training flight, myself and student were on an IFR flight plan in IMC conditions near reno at 12000 ft when our aircraft encountered light mixed ice. I requested a lower altitude. Center advised that no change (to lower) could be approved for 5 mins due to overtaking traffic at lower altitude. During the wait we lost our airspeed indicator (pitot heat was on). I informed center of the situation and became adamant in my request for a lower altitude. Center advised (issued) a descent from 12000 ft to 11000 ft. The student began a hasty descent, due to the ice situation. During this time the static system began to fail. I instructed the student to select alternate air, which he did and the static system was restored. At that point we realized that the indicated altitude was 10400 ft. After we arrested the descent, center asked our altitude, I replied 10400 ft. I mistakenly reported that I understood the assignment as 10000 ft. Due to the tense situation I, (in want of an excuse) wrongly stated this, knowing that the assignment was 11000 ft with the 5 min wait, and pitot static problem. We descended through our assigned altitude. The ice was light. We had checked for PIREPS on ice. We were certain that our trip would keep us out of the ice. We diverted to reno as a precaution and stayed the night to continue our trip the following day. During the trip we intended reno as a diversion in the event of inadvertent ice encounters.

Original NASA ASRS Text

Title: SMA ON IFR TRAINING FLT ENCOUNTERS ICE AT 12000 FT, LOSES STATIC INSTS AND REQUESTS LOWER ALT. WHEN FINALLY CLRED TO 11000 FT, DSCNT IS BEGUN. DURING DSCNT, ALT STATIC SOURCE IS SELECTED AND INDICATED ALT CHANGED TO 10400 FT. RATHER THAN EXPLAIN, RPTR TOLD ATC HE THOUGHT THEY WERE CLRED TO 10000 FT.

Narrative: DURING LONG IFR XCOUNTRY TRAINING FLT, MYSELF AND STUDENT WERE ON AN IFR FLT PLAN IN IMC CONDITIONS NEAR RENO AT 12000 FT WHEN OUR ACFT ENCOUNTERED LIGHT MIXED ICE. I REQUESTED A LOWER ALT. CTR ADVISED THAT NO CHANGE (TO LOWER) COULD BE APPROVED FOR 5 MINS DUE TO OVERTAKING TFC AT LOWER ALT. DURING THE WAIT WE LOST OUR AIRSPD INDICATOR (PITOT HEAT WAS ON). I INFORMED CTR OF THE SIT AND BECAME ADAMANT IN MY REQUEST FOR A LOWER ALT. CTR ADVISED (ISSUED) A DSCNT FROM 12000 FT TO 11000 FT. THE STUDENT BEGAN A HASTY DSCNT, DUE TO THE ICE SIT. DURING THIS TIME THE STATIC SYS BEGAN TO FAIL. I INSTRUCTED THE STUDENT TO SELECT ALTERNATE AIR, WHICH HE DID AND THE STATIC SYS WAS RESTORED. AT THAT POINT WE REALIZED THAT THE INDICATED ALT WAS 10400 FT. AFTER WE ARRESTED THE DSCNT, CTR ASKED OUR ALT, I REPLIED 10400 FT. I MISTAKENLY RPTED THAT I UNDERSTOOD THE ASSIGNMENT AS 10000 FT. DUE TO THE TENSE SIT I, (IN WANT OF AN EXCUSE) WRONGLY STATED THIS, KNOWING THAT THE ASSIGNMENT WAS 11000 FT WITH THE 5 MIN WAIT, AND PITOT STATIC PROB. WE DSNDED THROUGH OUR ASSIGNED ALT. THE ICE WAS LIGHT. WE HAD CHKED FOR PIREPS ON ICE. WE WERE CERTAIN THAT OUR TRIP WOULD KEEP US OUT OF THE ICE. WE DIVERTED TO RENO AS A PRECAUTION AND STAYED THE NIGHT TO CONTINUE OUR TRIP THE FOLLOWING DAY. DURING THE TRIP WE INTENDED RENO AS A DIVERSION IN THE EVENT OF INADVERTENT ICE ENCOUNTERS.

Data retrieved from NASA's ASRS site as of July 2007 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.