GA small transport had problem with radio memory.

Attributes
ACN	103582
Time
Date	198902
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bfl
State Reference	CA
Altitude	msl bound lower : 7000 msl bound upper : 7000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	general aviation : personal
Make Model Name	Small Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 6 flight time total : 4500
ASRS Report	103582
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

This small transport is equipped with the factory arc radios that feature 3 frequency memories per communication transceiver. This allows 3 preset frequencys, a great convenience except for the following flaw. During the above mentioned sequence usually under IMC in controled airspace, #2 communication had the incredible facility to change channels by itself! For example, we would set in a bur frequency of 135.20 on #2 memory and 132.90 on #3 of communication #2. When handed off from the former frequency to the latter, my partner and I would watch the rig change back to the former frequency all by itself within a minute or so. My partner and I are/were both aerospace engineers, and his specialty is electrical engineering (mine aeronautical). We believe this fault to be caused by dirty and loose contact in the navcom plus aeroelasticity aggravated by moderate turbulence. We became suspicious when the monitored frequency became very quiet. I don't believe we violated any far's during this experience, but certainly this condition warrants attention. (Other factors: 2 xponders dead, 75% of flight was IMC, #1 communication behaved itself.)

Original NASA ASRS Text

Title: GA SMT HAD PROBLEM WITH RADIO MEMORY.

Narrative: THIS SMT IS EQUIPPED WITH THE FACTORY ARC RADIOS THAT FEATURE 3 FREQ MEMORIES PER COM TRANSCEIVER. THIS ALLOWS 3 PRESET FREQS, A GREAT CONVENIENCE EXCEPT FOR THE FOLLOWING FLAW. DURING THE ABOVE MENTIONED SEQUENCE USUALLY UNDER IMC IN CTLED AIRSPACE, #2 COM HAD THE INCREDIBLE FAC TO CHANGE CHANNELS BY ITSELF! FOR EXAMPLE, WE WOULD SET IN A BUR FREQ OF 135.20 ON #2 MEMORY AND 132.90 ON #3 OF COM #2. WHEN HANDED OFF FROM THE FORMER FREQ TO THE LATTER, MY PARTNER AND I WOULD WATCH THE RIG CHANGE BACK TO THE FORMER FREQ ALL BY ITSELF WITHIN A MINUTE OR SO. MY PARTNER AND I ARE/WERE BOTH AEROSPACE ENGINEERS, AND HIS SPECIALTY IS ELECTRICAL ENGINEERING (MINE AERONAUTICAL). WE BELIEVE THIS FAULT TO BE CAUSED BY DIRTY AND LOOSE CONTACT IN THE NAVCOM PLUS AEROELASTICITY AGGRAVATED BY MODERATE TURB. WE BECAME SUSPICIOUS WHEN THE MONITORED FREQ BECAME VERY QUIET. I DON'T BELIEVE WE VIOLATED ANY FAR'S DURING THIS EXPERIENCE, BUT CERTAINLY THIS CONDITION WARRANTS ATTN. (OTHER FACTORS: 2 XPONDERS DEAD, 75% OF FLT WAS IMC, #1 COM BEHAVED ITSELF.)

Data retrieved from NASA's ASRS site as of August 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.