A tower controller observed a trainee's lack of knowledge regarding light signals.

Narrative:

A C172 came in NORDO. I issued light gun signals and after he was taxiing; I put the light gun away while I cleared another for take off. I noticed that the ground controller had grabbed his light gun and was issuing green/red I queried what he was doing and the controller said he was issuing taxi clearance. I then informed him that he was in fact flashing red/green which means exercise extreme caution. Not a bad thing to flash but the problem was that he wasn't aware that he was flashing the wrong instruction. This trainee needs more instruction on how to operate the light gun.

Original NASA ASRS Text

Title: A Tower Controller observed a Trainee's lack of knowledge regarding light signals.

Narrative: A C172 came in NORDO. I issued light gun signals and after he was taxiing; I put the light gun away while I cleared another for take off. I noticed that the Ground Controller had grabbed his light gun and was issuing green/red I queried what he was doing and the Controller said he was issuing taxi clearance. I then informed him that he was in fact flashing red/green which means exercise extreme caution. Not a bad thing to flash but the problem was that he wasn't aware that he was flashing the wrong instruction. This Trainee needs more instruction on how to operate the light gun.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1016047
Time
Date	201206
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Flight Phase	Taxi
Flight Plan	VFR
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy