D10 controller providing OJT experienced a loss of separation when the developmental failed to issue...

Narrative:

My developmental and I had two sessions on the departure one position; and I am not certain in which session the event occurred. The two aircraft departed on the same initial route. The trail aircraft was the B757. The B757 climbed rapidly and increased speed relative to the MD80. As the situation developed the developmental was exhibiting some indecisiveness; and I implored him to take action to insure separation if he felt a problem existed. He eventually climbed the trailing B757. I thought that we maintained vertical throughout; but while debriefing the developmental later in the shift he indicated that the aircraft was a 1000 ft higher than I thought. I saw at one point 8300 on the MD80 while the B757 was out of 9400. The data tags were overlapped so it is possible I misread one or both. Regardless of the outcome of this event; ojti's need (partially myself) to better balance the need for learning vs. A safe outcome. At times this is an extremely difficult call; but needs to be weighted towards maintaining separation standards. Perhaps a reminder to all ojti's that this is a problem and although it is a difficult decision operate conservative over trying to stretch a trainee.

Original NASA ASRS Text

Title: D10 Controller providing OJT experienced a loss of separation when the developmental failed to issue decisive and timely corrective action involving two air carrier departure aircraft.

Narrative: My Developmental and I had two sessions on the Departure one position; and I am not certain in which session the event occurred. The two aircraft departed on the same initial route. The trail aircraft was the B757. The B757 climbed rapidly and increased speed relative to the MD80. As the situation developed the Developmental was exhibiting some indecisiveness; and I implored him to take action to insure separation if he felt a problem existed. He eventually climbed the trailing B757. I thought that we maintained vertical throughout; but while debriefing the Developmental later in the shift he indicated that the aircraft was a 1000 FT higher than I thought. I saw at one point 8300 on the MD80 while the B757 was out of 9400. The data tags were overlapped so it is possible I misread one or both. Regardless of the outcome of this event; OJTI's need (partially myself) to better balance the need for learning vs. a safe outcome. At times this is an extremely difficult call; but needs to be weighted towards maintaining separation standards. Perhaps a reminder to all OJTI's that this is a problem and although it is a difficult decision operate conservative over trying to stretch a trainee.

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	886405
Time
Date	201005
Local Time Of Day	1801-2400
Place
Locale Reference	D10.TRACON
State Reference	TX
Aircraft 1
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Aircraft 2
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Person 1
Function	Departure
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Inflight Event / Encounter Other / Unknown

D10 controller providing OJT experienced a loss of separation when the developmental failed to issue decisive and timely corrective action involving two air carrier departure aircraft.