Flight crew set transponder to 7700 instead of the discrete code.

Attributes
ACN	103757
Time
Date	198902
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : abq
State Reference	NM
Altitude	msl bound lower : 6500 msl bound upper : 7000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : abq
Operator	general aviation : corporate
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 10 flight time total : 4900 flight time type : 15
ASRS Report	103757
Person 2
Affiliation	Other
Function	other personnel other
Qualification	pilot : private
Experience	flight time last 90 days : 7 flight time total : 325 flight time type : 0
ASRS Report	103296
Events
Anomaly	non adherence : far other anomaly other
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On 2/thur/89 I was piloting cap corp small aircraft on an air force authority/authorized search and rescue mission. I departed abq at approximately xa en route to my assigned search area grids 37, 38, 39. We passed through the arsa under control of abq departure. Upon reaching the limits of the arsa we were cleared to change radio frequencys and transponder code. I instructed the observer to set the transponder to XXXX, the discrete squawk code for search missions. The observer misunderstood the instruction and set the transponder to 7700. Shortly thereafter our search pattern took us out of radio line of sight from either ground or airborne radio units. We were unaware of any problem until our search pattern put us back into communication line of sight at which time our control aircraft informed us of the problem and we corrected the transponder setting. Recommendation: discrete transponder codes should not be issued containing digit combinations such as 77, 76, etc.

Original NASA ASRS Text

Title: FLT CREW SET TRANSPONDER TO 7700 INSTEAD OF THE DISCRETE CODE.

Narrative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

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.