A320 flight crew reported slowing early during approach via ILS prm 08L at atl due to the perception...

Narrative:

We were cleared for that ILS prm approach to runway 8L and told to maintain 160 knots to schel; the final approach fix. After intercepting the localizer the captain was concerned about our spacing and asked the approach controller how our spacing looked with the aircraft in front of us on the same approach. The approach controller said our spacing was fine. The captain then pointed out to me on our TCAS that we were only around three miles behind the aircraft in front of us. The aircraft in front of us slowed down even more and the captain started talking about a possible go around. About two miles before the schel intersection I asked the captain if I should manage my speed to slow down since we both felt like we were gaining on the aircraft in front of us. We both agreed to manage our speed. The approach controller was busy with other aircraft; and the captain was unable to tell him that we were slowing a little early.once we arrived over schel; the approach controller asked us why we had slowed early. The captain said because of our spacing and that we were trying to avoid a potential conflict. The controller said our spacing was fine. We were around 400 feet AGL on short final when the aircraft in front of us cleared the runway.with this event I was trying to avoid a potential conflict where the captain and I felt we had been vectored in too close to the aircraft in front of us. I should have maintained the assigned airspeed all the way up to schel and chose to go around if there was an issue at that point.

Original NASA ASRS Text

Title: A320 flight crew reported slowing early during approach via ILS PRM 08L at ATL due to the perception that they were gaining on the aircraft ahead; without advising ATC. ATC is not happy.

Narrative: We were cleared for that ILS PRM Approach to Runway 8L and told to maintain 160 knots to SCHEL; the final approach fix. After intercepting the localizer the Captain was concerned about our spacing and asked the Approach Controller how our spacing looked with the aircraft in front of us on the same approach. The Approach Controller said our spacing was fine. The Captain then pointed out to me on our TCAS that we were only around three miles behind the aircraft in front of us. The aircraft in front of us slowed down even more and the Captain started talking about a possible go around. About two miles before the SCHEL intersection I asked the Captain if I should manage my speed to slow down since we both felt like we were gaining on the aircraft in front of us. We both agreed to manage our speed. The Approach Controller was busy with other aircraft; and the Captain was unable to tell him that we were slowing a little early.Once we arrived over SCHEL; the Approach Controller asked us why we had slowed early. The Captain said because of our spacing and that we were trying to avoid a potential conflict. The controller said our spacing was fine. We were around 400 feet AGL on short final when the aircraft in front of us cleared the runway.With this event I was trying to avoid a potential conflict where the Captain and I felt we had been vectored in too close to the aircraft in front of us. I should have maintained the assigned airspeed all the way up to SCHEL and chose to go around if there was an issue at that point.

Data retrieved from NASA's ASRS site 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	1385200
Time
Date	201609
Local Time Of Day	1801-2400
Place
Locale Reference	ATL.Airport
State Reference	GA
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Other ILS PRM RWY 8L
Flight Plan	IFR
Aircraft 2
Make Model Name	Medium Large Transport
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Speed All Types

A320 flight crew reported slowing early during approach via ILS prm 08L at atl due to the perception that they were gaining on the aircraft ahead; without advising ATC. ATC is not happy.