Air Traffic Control Fully Certified
Situational Awareness
ATC Issue All Types
General None Reported / Taken
Human Factors; Procedure
I was relieving Clearance Delivery; the Supervisor was also being relieved. The ASDE-X went off for 27R and 35 converging. The Controller on Local East took no action. Both 27R (an E190) and 35 (a CRJ2) aircraft landed and a [Runaway] 35 departure was at the end of the runway. I don't know if this was legal; it was certainly the tightest 27R and 35 I have ever seen in many years at PHL; and this operation is our standard. I believe this to be very dangerous; even if the operation were legal. I think it is highly likely that the pilots may choose to go around on their own; and if both aircraft's pilots made that decision simultaneously it could be disastrous given that both would be a tie in the air with noses up and unable to see one another. I believe this has been reported as an issue in the past. There was to have been a work group to study this operation. I do not think it was ever formed. So far as I know; management at PHL has taken no action. I suggest this work group be formed. It has also generally been practice to send one aircraft [around]if the ASDE goes off with the converging when in this operation. I don't know if that is suggested practice; but if so; perhaps the facility should be reminded of it.
PHL Controller witnessed an ASDE-X conflict alert that was unheeded by the Local Controller. The reporter notes this type of no-action event is on-going and very dangerous.