Dfw controller described RNAV departure event when two successive aircraft strayed off the RNAV rout...

Narrative:

I was working the local east 1 and 3 combined. Dfw airport was VFR and we were conducting RNAV departures and visual arrivals. Two departures in a row are involved in this report; the first (air carrier X) departed and the second (air carrier Y) a few minutes later. As air carrier X was climbing out on the jaspa departure; I noticed that the aircraft's radar target was west of the depicted flight path on my racd. I advised the tower supervisor that the aircraft were drifting toward the west side and asked if I should discontinue RNAV departures and assign headings to remain in compliance with the dfw/D10 departure waiver which requires that initial runway separation between east and west side departures had to be maintained at all times. The supervisor's 'no' made me raise my eyebrows in disbelief. A few moments later air carrier Y departed on the soldo departure and performed similarly to air carrier X. Fortunately there weren't any departures off the west side at the time so traffic was not a factor. The agency has mandated that we monitor the RNAV departures to ensure 'compliance and conformance with the RNAV SID'. But now by the supervisors' actions they have said that they really don't care if separation is maintained or not; they only care if we have to stop using the RNAV departures. Recommendation; discontinue the use of RNAV off the ground procedures until a safer procedure can be created and verified as safe. If the aircraft were to depart the runway; make a turn that creates 15 degrees separation from the other side's departures and climb to a reasonable altitude prior to engaging RNAV. We could: 1. Discontinue the excess phraseology of 'RNAV to (first fix); runway xx; cleared for takeoff'. 2. Discontinue the practice of monitoring the first few miles of the departure by the tower; giving the departure controller quicker control of the aircraft. 3. Ensure that departures off opposing sides of dfw airport are actually separated rather than just launched into a questionable situation.

Original NASA ASRS Text

Title: DFW Controller described RNAV departure event when two successive aircraft strayed off the RNAV routing; reporter was instructed to not intervene with corrective instructions; reporter suggesting discontinuing RNAV procedures until procedures are reviewed.

Narrative: I was working the Local East 1 and 3 combined. DFW Airport was VFR and we were conducting RNAV departures and visual arrivals. Two departures in a row are involved in this report; the first (Air Carrier X) departed and the second (Air Carrier Y) a few minutes later. As Air Carrier X was climbing out on the JASPA departure; I noticed that the aircraft's radar target was west of the depicted flight path on my RACD. I advised the Tower Supervisor that the aircraft were drifting toward the west side and asked if I should discontinue RNAV departures and assign headings to remain in compliance with the DFW/D10 departure waiver which requires that initial runway separation between east and west side departures had to be maintained at all times. The supervisor's 'no' made me raise my eyebrows in disbelief. A few moments later Air Carrier Y departed on the SOLDO departure and performed similarly to Air Carrier X. Fortunately there weren't any departures off the west side at the time so traffic was not a factor. The agency has mandated that we monitor the RNAV departures to ensure 'compliance and conformance with the RNAV SID'. But now by the supervisors' actions they have said that they really don't care if separation is maintained or not; they only care if we have to stop using the RNAV departures. Recommendation; discontinue the use of RNAV off the ground procedures until a safer procedure can be created and verified as safe. If the aircraft were to depart the runway; make a turn that creates 15 degrees separation from the other side's departures and climb to a reasonable altitude prior to engaging RNAV. We could: 1. Discontinue the excess phraseology of 'RNAV to (first fix); Runway XX; cleared for takeoff'. 2. Discontinue the practice of monitoring the first few miles of the departure by the Tower; giving the Departure Controller quicker control of the aircraft. 3. Ensure that departures off opposing sides of DFW airport are actually separated rather than just launched into a questionable situation.

Data retrieved from NASA's ASRS site as of April 2012 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	872876
Time
Date	201002
Local Time Of Day	1201-1800
Place
Locale Reference	DFW.Tower
State Reference	TX
Aircraft 1
Make Model Name	Medium Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Initial Climb
Route In Use	SID JASPA
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Initial Climb
Route In Use	SID SOLDO
Flight Plan	IFR
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

Dfw controller described RNAV departure event when two successive aircraft strayed off the RNAV routing; reporter was instructed to not intervene with corrective instructions; reporter suggesting discontinuing RNAV procedures until procedures are reviewed.