An small aircraft had an instrument failure in solid IMC.

Attributes
ACN	255677
Time
Date	199310
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : lwm airport : bed
State Reference	MA
Altitude	msl bound lower : 400 msl bound upper : 2000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bos
Operator	general aviation : instructional
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other other other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	instruction : instructor
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 113 flight time total : 1630 flight time type : 340
ASRS Report	255677
Person 2
Affiliation	Other
Function	instruction : trainee
Qualification	pilot : private
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other spatial deviation other spatial deviation
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : provided flight assist flight crew : became reoriented flight crew : overcame equipment problem flight crew : declared emergency other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Aircraft

Narrative:

In sum: an instructor pilot in an small aircraft with an instrument trainee had several failures while in solid IMC. Both the attitude and heading gyroscopes failed and were covered up by the reporting instructor. The turn coordinator was unreliable and 'overly sensitive.' the ADF and VOR/ILS receivers were both swinging wildly on one set of stations but worked all right on another. As the airspeed built and the altitude decreased, the instructor closed the throttle, trimmed the aircraft, and hoped for the best. The best happened. The aircraft came into the clear. The reporter followed a highway system to an apt and landed successfully. ZBW helped with vectors while the aircraft was still in the clouds. The gyroscope instruments had mechanical failures. The electrical system was thought to have had a 'brown out' with the heavy electrical loads on it and a possible slipping belt in heavy moisture. The reporting instructor attributes his continuing life to his study of the system, constant reading of other peoples' solutions to problems, and a recent period in the simulator under partial panel conditions.

Original NASA ASRS Text

Title: AN SMA HAD AN INST FAILURE IN SOLID IMC.

Narrative: IN SUM: AN INSTRUCTOR PLT IN AN SMA WITH AN INST TRAINEE HAD SEVERAL FAILURES WHILE IN SOLID IMC. BOTH THE ATTITUDE AND HDG GYROSCOPES FAILED AND WERE COVERED UP BY THE RPTING INSTRUCTOR. THE TURN COORDINATOR WAS UNRELIABLE AND 'OVERLY SENSITIVE.' THE ADF AND VOR/ILS RECEIVERS WERE BOTH SWINGING WILDLY ON ONE SET OF STATIONS BUT WORKED ALL RIGHT ON ANOTHER. AS THE AIRSPD BUILT AND THE ALT DECREASED, THE INSTRUCTOR CLOSED THE THROTTLE, TRIMMED THE ACFT, AND HOPED FOR THE BEST. THE BEST HAPPENED. THE ACFT CAME INTO THE CLR. THE RPTR FOLLOWED A HWY SYS TO AN APT AND LANDED SUCCESSFULLY. ZBW HELPED WITH VECTORS WHILE THE ACFT WAS STILL IN THE CLOUDS. THE GYROSCOPE INSTS HAD MECHANICAL FAILURES. THE ELECTRICAL SYS WAS THOUGHT TO HAVE HAD A 'BROWN OUT' WITH THE HVY ELECTRICAL LOADS ON IT AND A POSSIBLE SLIPPING BELT IN HVY MOISTURE. THE RPTING INSTRUCTOR ATTRIBUTES HIS CONTINUING LIFE TO HIS STUDY OF THE SYS, CONSTANT READING OF OTHER PEOPLES' SOLUTIONS TO PROBS, AND A RECENT PERIOD IN THE SIMULATOR UNDER PARTIAL PANEL CONDITIONS.

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.