Narrative:

While I was working local assist; the llocal controller cleared aircraft X for takeoff; and then put aircraft Y into position. As soon as aircraft X started his southbound turn off the departure end; the local controller then cleared aircraft Y for takeoff. I told him that I thought that it was too close; but he didn't do anything about it. It appeared that there was not sufficient wake turbulence separation. Then; about 5 minutes later; the local controller cleared aircraft Z for takeoff and put aircraft west into position. As soon as aircraft Z started his turn off departure end; the local controller cleared aircraft west for takeoff. I told him again that it was probably too close. Then I told the supervisor that it looked too close both times and I didn't want to be his 'controller B.' this time there was a little more separation than the first; but it still appeared that there may not have been the appropriate wake turbulence separation.need some clarification of how exactly to calculate wake turbulence with a departure/departure; when the leading aircraft is a heavy or B757. Include runway lengths as separation? What about diverging courses?

Related reports:

Google
 

Original NASA ASRS Text

Title: Two ONT Tower Controllers report of a possible lack of separation due to departing the aircraft too soon.

Narrative: While I was working local assist; the lLocal Controller cleared Aircraft X for takeoff; and then put Aircraft Y into position. As soon as Aircraft X started his southbound turn off the departure end; the Local Controller then cleared Aircraft Y for takeoff. I told him that I thought that it was too close; but he didn't do anything about it. It appeared that there was not sufficient wake turbulence separation. Then; about 5 minutes later; the Local Controller cleared Aircraft Z for takeoff and put Aircraft W into position. As soon as Aircraft Z started his turn off departure end; the Local Controller cleared Aircraft W for takeoff. I told him again that it was probably too close. Then I told the Supervisor that it looked too close both times and I didn't want to be his 'Controller B.' This time there was a little more separation than the first; but it still appeared that there may not have been the appropriate wake turbulence separation.Need some clarification of how exactly to calculate wake turbulence with a departure/departure; when the leading aircraft is a Heavy or B757. Include runway lengths as separation? What about diverging courses?

Data retrieved from NASA's ASRS site 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.