Mci controller experienced operational error at 3000 ft with two aircraft on final. Wake separation ...

Narrative:

I was working arrival during the situation. Aircraft X (a B737) was following aircraft Y (a heavy B767) on the ILS to runway 19R at mci. The required wake turbulence separation is 5 miles. I turned aircraft Y onto final and cleared him for the approach to maintain 170 KTS or greater to the FAF. I had aircraft X reduced to 190 KTS on a base leg. I let aircraft X go through final for extra spacing and then turned him to join the localizer at about 12 miles; reducing to 170 KTS. At this time I had about 6 1/2 miles separation with aircraft X slowing. I cleared aircraft X for the approach at 170 KTS or less. I did not get an indication that he had slowed enough to maintain separation; so I slowed aircraft X to 150 KTS or less. When the aircraft got to about 5 1/4 miles I was still not satisfied with the speed of aircraft X (180 KIAS) and was going to give it 1 more sweep to see how much speed he could lose. In the next sweep; no speed was lost so I issued a breakout to aircraft X. The pilot paused and said 'was that for aircraft X?' I replied 'affirmative; aircraft X; approach clearance canceled; turn right heading 270 degrees; maintain 3000 ft.' the pilot then acknowledged the instruction. From the time I issued the first breakout to the time the computer recorded a loss of separation was a full 17 seconds. I took the appropriate action; the pilot did not acknowledge in a timely manner. Had he done so; separation would not have been lost.

Original NASA ASRS Text

Title: MCI Controller experienced operational error at 3000 FT with two aircraft on final. Wake separation was compromised when second aircraft was slow to respond to the reporters corrective break out action.

Narrative: I was working arrival during the situation. Aircraft X (a B737) was following Aircraft Y (a Heavy B767) on the ILS to Runway 19R at MCI. The required wake turbulence separation is 5 miles. I turned Aircraft Y onto final and cleared him for the approach to maintain 170 KTS or greater to the FAF. I had Aircraft X reduced to 190 KTS on a base leg. I let Aircraft X go through final for extra spacing and then turned him to join the LOC at about 12 miles; reducing to 170 KTS. At this time I had about 6 1/2 miles separation with Aircraft X slowing. I cleared Aircraft X for the approach at 170 KTS or less. I did not get an indication that he had slowed enough to maintain separation; so I slowed Aircraft X to 150 KTS or less. When the aircraft got to about 5 1/4 miles I was still not satisfied with the speed of Aircraft X (180 KIAS) and was going to give it 1 more sweep to see how much speed he could lose. In the next sweep; no speed was lost so I issued a breakout to Aircraft X. The pilot paused and said 'Was that for Aircraft X?' I replied 'Affirmative; Aircraft X; approach clearance canceled; turn right heading 270 degrees; maintain 3000 FT.' The pilot then acknowledged the instruction. From the time I issued the first breakout to the time the computer recorded a loss of separation was a full 17 seconds. I took the appropriate action; the pilot did not acknowledge in a timely manner. Had he done so; separation would not have been lost.

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	828579
Time
Date	200903
Local Time Of Day	1801-2400
Place
Locale Reference	MCI.Airport
State Reference	FL
Environment
Flight Conditions	Marginal
Light	Dusk
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Approach Departure
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 1
Events
Anomaly	ATC Issue All Types

Mci controller experienced operational error at 3000 ft with two aircraft on final. Wake separation was compromised when second aircraft was slow to respond to the reporters corrective break out action.