C172 instructor flew with the transponder not installed.

Attributes
ACN	488040
Time
Date	200010
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : zzz.tower
Operator	general aviation : instructional
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	climbout : vacating altitude cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	instruction : instructor oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : cfi pilot : multi engine
Experience	flight time last 90 days : 100 flight time total : 300 flight time type : 150
ASRS Report	488040
Person 2
Affiliation	other
Function	flight crew : single pilot instruction : trainee
Qualification	pilot : student
Events
Anomaly	non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted none taken : detected after the fact
Consequence	other
Factors
Maintenance	contributing factor : schedule pressure performance deficiency : non compliance with legal requirements performance deficiency : logbook entry
Supplementary
Problem Areas	Flight Crew Human Performance Company Aircraft Maintenance Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

The mode C transponder was removed from the airplane after hours without the knowledge of the flying club. My student had preflted and I did not notice that the transponder had been removed until after departure. Our club has a policy of leaving the xponders on at all times to avoid forgetting to turn them on. I feel that since I was used to not having to turn the transponder on, I simply missed even looking down at the transponder. I am certainly aware of the need to properly inspect the airplane prior to flight, and I can assure you that this type of mistake will not happen again.

Original NASA ASRS Text

Title: C172 INSTRUCTOR FLEW WITH THE XPONDER NOT INSTALLED.

Narrative: THE MODE C XPONDER WAS REMOVED FROM THE AIRPLANE AFTER HRS WITHOUT THE KNOWLEDGE OF THE FLYING CLUB. MY STUDENT HAD PREFLTED AND I DID NOT NOTICE THAT THE XPONDER HAD BEEN REMOVED UNTIL AFTER DEP. OUR CLUB HAS A POLICY OF LEAVING THE XPONDERS ON AT ALL TIMES TO AVOID FORGETTING TO TURN THEM ON. I FEEL THAT SINCE I WAS USED TO NOT HAVING TO TURN THE XPONDER ON, I SIMPLY MISSED EVEN LOOKING DOWN AT THE XPONDER. I AM CERTAINLY AWARE OF THE NEED TO PROPERLY INSPECT THE AIRPLANE PRIOR TO FLT, AND I CAN ASSURE YOU THAT THIS TYPE OF MISTAKE WILL NOT HAPPEN AGAIN.

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.