Air carrier X had less than standard separation from air carrier Y. System error.

Attributes
ACN	211253
Time
Date	199206
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sac
State Reference	CA
Altitude	msl bound lower : 11000 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sac
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute : direct enroute airway : zoa
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : departure instruction : instructor
Qualification	controller : radar
Experience	controller radar : 24
ASRS Report	211253
Person 2
Affiliation	government : faa
Function	controller : departure instruction : trainee
Qualification	controller : developmental
ASRS Report	211254
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other other : unspecified atc
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated
Miss Distance	horizontal : 27000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Intra Facility Coordination Failure Operational Error

Narrative:

I was conducting OJT on the east feeder position. We were working 2 air carrier aircraft off smf on frogo 6 SID. The first aircraft air carrier X was transferred to ZOA out of about 9000 climbing to 11000. The second air carrier Y was transferred less than a min later leveling at 11000, 5.2 mi in trail. Once level the air carrier Y rapidly increased speed and with air carrier X still climbing standard separation was lost. The problem arose with instructors failure to realize the type aircraft involved, and not anticipating speed increase by air carrier Y. Supplemental information from acn 211254. Air carrier X was climbing out of 9500 ft going to 11000 and switched to ZOA. Air carrier Y 5 mi in trail of air carrier X was switched to ZOA level at 11000. Air carrier Y increased speed resulting in reduced separation.

Original NASA ASRS Text

Title: ACR X HAD LTSS FROM ACR Y. SYS ERROR.

Narrative: I WAS CONDUCTING OJT ON THE E FEEDER POS. WE WERE WORKING 2 ACR ACFT OFF SMF ON FROGO 6 SID. THE FIRST ACFT ACR X WAS TRANSFERRED TO ZOA OUT OF ABOUT 9000 CLBING TO 11000. THE SECOND ACR Y WAS TRANSFERRED LESS THAN A MIN LATER LEVELING AT 11000, 5.2 MI IN TRAIL. ONCE LEVEL THE ACR Y RAPIDLY INCREASED SPD AND WITH ACR X STILL CLBING STANDARD SEPARATION WAS LOST. THE PROBLEM AROSE WITH INSTRUCTORS FAILURE TO REALIZE THE TYPE ACFT INVOLVED, AND NOT ANTICIPATING SPD INCREASE BY ACR Y. SUPPLEMENTAL INFO FROM ACN 211254. ACR X WAS CLBING OUT OF 9500 FT GOING TO 11000 AND SWITCHED TO ZOA. ACR Y 5 MI IN TRAIL OF ACR X WAS SWITCHED TO ZOA LEVEL AT 11000. ACR Y INCREASED SPD RESULTING IN REDUCED SEPARATION.

Data retrieved from NASA's ASRS site as of July 2007 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.