Emb-175 first officer reported encountering wake turbulence on approach to lax in trail of a B757. R...

Narrative:

Approach turned a 757 in front of us when on final. We were assigned 160 to the FAF and felt the separation was less than desirable. As a crew we both expressed concern with the spacing of us and the 757. When handed off to tower I asked to slow down to increase separation. Tower then asked what speed I was assigned. I said 160 to the FAF. There was no response.we encountered wake turbulence on short final with strong rolling moments. It was manageable; but not desirable. I got on the radios after and told ATC about the wake turbulence and that's why we requested slower. Tower said it was out of their hands and approach was responsible. Tower did not seem the least bit concerned for our safety when I asked for the slower speed. It is troubling and that's why I'm writing this report. While we were not in any danger; the lack of concern for our requests bothers me. We could execute a go-around or be more persistent with our request to slow down.

Original NASA ASRS Text

Title: EMB-175 First Officer reported encountering wake turbulence on approach to LAX in trail of a B757. Reporter felt ATC was unresponsive to his concerns.

Narrative: Approach turned a 757 in front of us when on final. We were assigned 160 to the FAF and felt the separation was less than desirable. As a crew we both expressed concern with the spacing of us and the 757. When handed off to tower I asked to slow down to increase separation. Tower then asked what speed I was assigned. I said 160 to the FAF. There was no response.We encountered wake turbulence on short final with strong rolling moments. It was manageable; but not desirable. I got on the radios after and told ATC about the wake turbulence and that's why we requested slower. Tower said it was out of their hands and Approach was responsible. Tower did not seem the least bit concerned for our safety when I asked for the slower speed. It is troubling and that's why I'm writing this report. While we were not in any danger; the lack of concern for our requests bothers me. We could execute a go-around or be more persistent with our request to slow down.

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	1317981
Time
Date	201512
Local Time Of Day	1801-2400
Place
Locale Reference	LAX.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	EMB ERJ 170/175 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Inflight Event / Encounter Wake Vortex Encounter

Emb-175 first officer reported encountering wake turbulence on approach to lax in trail of a B757. Reporter felt ATC was unresponsive to his concerns.