B767 first officer reported deviating from assigned speed on approach to egll; citing wake turbulenc...

Attributes
ACN	1251022
Time
Date	201503
Place
Locale Reference	EGLL.Airport
State Reference	FO
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	Landing
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 9000 Flight Crew Type 180
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Speed All Types Inflight Event / Encounter Wake Vortex Encounter

Narrative:

During final approach to runway 27L into egll; we were given instructions to maintain 160kt until 4 DME. On approach we experienced an auto throttle (a/T) failure; as it disconnected automatically. We attempted to reengage the a/T twice with no success. Also we started to experience wake turbulence from the heavy aircraft in front of us and separation looked close. The captain instinctively slowed to target speed just prior to 4 DME to maintain safe operation of the approach. After landing ground control queried why we slowed down. We responded that we had experienced wake turbulence. In my opinion; the distractions of the a/T; the wake turbulence with reduced separation; combined with a very late landing clearance inhibited us in reporting our reduction of speed just prior to 4 DME.

Original NASA ASRS Text

Title: B767 First Officer reported deviating from assigned speed on approach to EGLL; citing wake turbulence and an autothrottle anomaly as contributing factors.

Narrative: During final approach to runway 27L into EGLL; we were given instructions to maintain 160kt until 4 DME. On approach we experienced an Auto Throttle (A/T) failure; as it disconnected automatically. We attempted to reengage the A/T twice with no success. Also we started to experience wake turbulence from the heavy aircraft in front of us and separation looked close. The Captain instinctively slowed to target speed just prior to 4 DME to maintain safe operation of the approach. After landing Ground Control queried why we slowed down. We responded that we had experienced wake turbulence. In my opinion; the distractions of the A/T; the wake turbulence with reduced separation; combined with a very late landing clearance inhibited us in reporting our reduction of speed just prior to 4 DME.

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.

B767 first officer reported deviating from assigned speed on approach to egll; citing wake turbulence and an autothrottle anomaly as contributing factors.