Emb captain reported track and altitude deviations on approach to dfw; citing a wake turbulence enco...

Narrative:

The event began when we were cleared for the ILS 36L. We were following a heavy 777. Weather conditions were IMC with constant chop caused by light to moderate precipitation. The autopilot significantly undershot the localizer while attempting to capture from a normal 30 degree intercept. The aircraft began a series of sweeping turns to regain the course. The aircraft's reaction very well may have been caused by wake turbulence from the preceding heavy. The pilot flying disconnected the autopilot and set an appropriate heading to capture the localizer. While doing so; the aircraft's altitude climbed to approximately 3400 feet MSL. I noticed the aircraft in a climb and called out the altitude deviation. As pilot flying was correcting back to the original altitude of 3000 feet MSL; approach control monitor queried our altitude. As we corrected back to 3000 feet MSL; we had joined the glide slope. We continued the approach to a normal landing. The autopilot's poor performance; subsequent intervention; and potential wake encounter caused the aircraft to abruptly roll. This; I believe; caused both myself and pilot flying to fixate on correcting the roll attitude and focus on guiding the aircraft back to the localizer. By the time the altitude deviation was recognized; ATC had queried us regarding our altitude. I believe that myself and pilot flying were faced with a challenging situation that presented itself abruptly in poor weather conditions. I think we were correct in disengaging the autopilot and focusing instead on flying the aircraft; however; we should have maintained more vigilant on our scan. I believe the emb's automation should be updated to allow for a more gradual and accurate localizer intercept. Additionally; I believe having smaller aircraft intercept the localizer at a point downwind of where a preceding heavy aircraft intercepted would lead to reduced wake encounters.

Original NASA ASRS Text

Title: EMB Captain reported track and altitude deviations on approach to DFW; citing a wake turbulence encounter and poor aircraft autoflight performance as contributing.

Narrative: The event began when we were cleared for the ILS 36L. We were following a heavy 777. Weather conditions were IMC with constant chop caused by light to moderate precipitation. The autopilot significantly undershot the localizer while attempting to capture from a normal 30 degree intercept. The aircraft began a series of sweeping turns to regain the course. The aircraft's reaction very well may have been caused by wake turbulence from the preceding heavy. The Pilot Flying disconnected the autopilot and set an appropriate heading to capture the localizer. While doing so; the aircraft's altitude climbed to approximately 3400 feet MSL. I noticed the aircraft in a climb and called out the altitude deviation. As Pilot Flying was correcting back to the original altitude of 3000 feet MSL; Approach Control monitor queried our altitude. As we corrected back to 3000 feet MSL; we had joined the glide slope. We continued the approach to a normal landing. The autopilot's poor performance; subsequent intervention; and potential wake encounter caused the aircraft to abruptly roll. This; I believe; caused both myself and pilot flying to fixate on correcting the roll attitude and focus on guiding the aircraft back to the localizer. By the time the altitude deviation was recognized; ATC had queried us regarding our altitude. I believe that myself and Pilot Flying were faced with a challenging situation that presented itself abruptly in poor weather conditions. I think we were correct in disengaging the autopilot and focusing instead on flying the aircraft; however; we should have maintained more vigilant on our scan. I believe the EMB's automation should be updated to allow for a more gradual and accurate localizer intercept. Additionally; I believe having smaller aircraft intercept the localizer at a point downwind of where a preceding heavy aircraft intercepted would lead to reduced wake encounters.

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	1728824
Time
Date	202002
Local Time Of Day	0601-1200
Place
Locale Reference	DFW.Airport
State Reference	TX
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	Embraer Jet Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Track / Heading All Types Inflight Event / Encounter Wake Vortex Encounter Inflight Event / Encounter Weather / Turbulence

Emb captain reported track and altitude deviations on approach to dfw; citing a wake turbulence encounter and poor aircraft autoflight performance as contributing.