P80 controller vectors aircraft onto final and notices the track jump. Controller thinks the jump is...

Attributes
ACN	1226215
Time
Date	201412
Local Time Of Day	1801-2400
Place
Locale Reference	HIO.Airport
State Reference	OR
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 2
Events
Anomaly	Airspace Violation All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Track / Heading All Types Inflight Event / Encounter CFTT / CFIT

Narrative:

Aircraft X was on vectors for hio ILS ry 13 approach. I issued the approach clearance after vectoring them through the final for in-trail spacing. I got a good readback for the clearance and altitude to maintain. Approximately 2 minutes later I noticed the track jump; but since we use fusion radar with only two primary radar inputs I assumed it was related to the radar. When the track did not return after a few seconds; I verified they were on the approach. I realized they were off course and descending through the MVA so I issued a low altitude alert and climbed them to 040. They descended to 030 in a 035 MVA before climbing back up. I canceled the approach clearance and issued vectors to re-join the approach. They flew through the localizer again; and after I corrected their heading to join I issued a new approach clearance.I believe flight training was in progress and the weather was IMC. I don't know what caused the aircraft to veer off course; I'm just glad I caught it.

Original NASA ASRS Text

Title: P80 controller vectors aircraft onto final and notices the track jump. Controller thinks the jump is related to FUSION radar. Issues another heading and the aircraft finally gets on final after third attempt. Aircraft enters lower MVA due to not turning correctly.

Narrative: Aircraft X was on vectors for HIO ILS RY 13 approach. I issued the approach clearance after vectoring them through the final for in-trail spacing. I got a good readback for the clearance and altitude to maintain. Approximately 2 minutes later I noticed the track jump; but since we use FUSION radar with only two primary radar inputs I assumed it was related to the radar. When the track did not return after a few seconds; I verified they were on the approach. I realized they were off course and descending through the MVA so I issued a Low Altitude Alert and climbed them to 040. They descended to 030 in a 035 MVA before climbing back up. I canceled the approach clearance and issued vectors to re-join the approach. They flew through the localizer again; and after I corrected their heading to join I issued a new approach clearance.I believe flight training was in progress and the weather was IMC. I don't know what caused the aircraft to veer off course; I'm just glad I caught it.

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.

P80 controller vectors aircraft onto final and notices the track jump. Controller thinks the jump is related to fusion radar. Issues another heading and the aircraft finally gets on final after third attempt. Aircraft enters lower MVA due to not turning correctly.