Narrative:

I was training a developmental on local with a C172 and 2 R22 helicopters in the pattern. The second R22 was sequenced behind the C172 who was #1. As the C172 was approaching the runway; it appeared that either the helicopter was following too close or making an approach to the parallel taxiway which is used occasionally. As I transmitted to the helicopter to verify he was in fact following the C172; the C172 told me that he was going around due to the R22 cutting him off. Since it was nighttime; it was impossible to ascertain there was a problem due to the angle from the tower to the runway and due to the R22's different landing light.

Related reports:

Google
 

Original NASA ASRS Text

Title: PRC Local Controller described conflict event when a helicopter allegedly cut off C172 traffic he/she was following; controller claiming developing problem was not identifiable because of nighttime conditions and visibility angle.

Narrative: I was training a developmental on Local with a C172 and 2 R22 helicopters in the pattern. The second R22 was sequenced behind the C172 who was #1. As the C172 was approaching the runway; it appeared that either the helicopter was following too close or making an approach to the parallel taxiway which is used occasionally. As I transmitted to the helicopter to verify he was in fact following the C172; the C172 told me that he was going around due to the R22 cutting him off. Since it was nighttime; it was impossible to ascertain there was a problem due to the angle from the Tower to the runway and due to the R22's different landing light.

Data retrieved from NASA's ASRS site as of May 2009 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.