A C172 pilot accidentally sets his transponder code to 7700 on a touch-and-go landing at pao.

Attributes
ACN	429287
Time
Date	199902
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : pao.airport
State Reference	CA
Altitude	msl single value : 500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : pao.tower
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	climbout : initial landing : touch and go
Route In Use	approach : traffic pattern departure : vfr
Flight Plan	None
Person 1
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 1.2 flight time total : 452 flight time type : 120
ASRS Report	429287
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	non adherence : published procedure non adherence other
Independent Detector	atc equipment other atc equipment : radar other controllera
Resolutory Action	controller : issued advisory flight crew : became reoriented
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

Reporter was in closed right traffic for runway 30 at pao airport. He had just executed a full flap touch-and-go landing and was turning to crosswind leg of pattern when tower asked if reporter was declaring an emergency (by means of transponder code 7700). A quick examination of transponder control panel revealed code 7700 displayed! Reporter advised tower that there was no emergency and immediately reset transponder code to 1200. Chain of events: 1) transponder on reporter's flying club aircraft has 4 levers rather than knobs to input code numbers. Levers project far enough that careless operation of flap control lever to 'up' by reporter's hand apparently reset code from 1200 to 7700! (Thank god it wasn't 7500.) 2) reporter had not encountered a lever-type transponder before and will take greater care when his hand is performing tasks in its vicinity. 3) following completion of training flight, reporter secured club aircraft and drove to base of airport control tower. Using telephone, reporter explained how he believed transponder had been reset to 7700. Tower person assured reporter that ATC (bay approach) had been informed, and the situation had been resolved.

Original NASA ASRS Text

Title: A C172 PLT ACCIDENTALLY SETS HIS XPONDER CODE TO 7700 ON A TOUCH-AND-GO LNDG AT PAO.

Narrative: RPTR WAS IN CLOSED R TFC FOR RWY 30 AT PAO ARPT. HE HAD JUST EXECUTED A FULL FLAP TOUCH-AND-GO LNDG AND WAS TURNING TO XWIND LEG OF PATTERN WHEN TWR ASKED IF RPTR WAS DECLARING AN EMER (BY MEANS OF XPONDER CODE 7700). A QUICK EXAM OF XPONDER CTL PANEL REVEALED CODE 7700 DISPLAYED! RPTR ADVISED TWR THAT THERE WAS NO EMER AND IMMEDIATELY RESET XPONDER CODE TO 1200. CHAIN OF EVENTS: 1) XPONDER ON RPTR'S FLYING CLUB ACFT HAS 4 LEVERS RATHER THAN KNOBS TO INPUT CODE NUMBERS. LEVERS PROJECT FAR ENOUGH THAT CARELESS OP OF FLAP CTL LEVER TO 'UP' BY RPTR'S HAND APPARENTLY RESET CODE FROM 1200 TO 7700! (THANK GOD IT WASN'T 7500.) 2) RPTR HAD NOT ENCOUNTERED A LEVER-TYPE XPONDER BEFORE AND WILL TAKE GREATER CARE WHEN HIS HAND IS PERFORMING TASKS IN ITS VICINITY. 3) FOLLOWING COMPLETION OF TRAINING FLT, RPTR SECURED CLUB ACFT AND DROVE TO BASE OF ARPT CTL TWR. USING TELEPHONE, RPTR EXPLAINED HOW HE BELIEVED XPONDER HAD BEEN RESET TO 7700. TWR PERSON ASSURED RPTR THAT ATC (BAY APCH) HAD BEEN INFORMED, AND THE SIT HAD BEEN RESOLVED.

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.