ZSU controller observed an aircraft intercepting the final approach course at 1800 feet. The assigne...

Narrative:

Aircraft X was being vectored for the ILS runway 10 approach at st. Thomas airport (stt). Aircraft was proceeding on a southbound heading and descending to 3000 feet. Minutes later the pilot asked if he could descend to 2800 feet and I proceeded to grant the request. After the aircraft was cleared I observed aircraft X was intercepting the final approach at 1800 feet instead of the 2800 feet assigned. Minimum vectoring altitude in the area was 2700 feet and intercept altitude for the ILS is 2800 feet.we were having problems on all frequencies and reception was sometimes [weak] with a lot of static on some readbacks. Main transmitters were out of service and backup frequency 132.25 was out of service because of bleed over issues on center frequencies. At the same time I was clearing aircraft X for the approach; I was asked to do a radio check on the main transmitters on 128.65. I believe the poor reception in the frequencies and the distraction of doing a radio check caused me to miss a possible wrong readback and lose my scanning at the moment. The poor radio frequency reception on 128.65 has been an ongoing problem for months and unless something serious is done to rectify this problem I fear that a worse incident might occur.

Original NASA ASRS Text

Title: ZSU Controller observed an aircraft intercepting the final approach course at 1800 feet. The assigned altitude to intercept was 2800 feet and the MVA is 2700 feet.

Narrative: Aircraft X was being vectored for the ILS RWY 10 approach at St. Thomas Airport (STT). Aircraft was proceeding on a southbound heading and descending to 3000 feet. Minutes later the pilot asked if he could descend to 2800 feet and I proceeded to grant the request. After the aircraft was cleared I observed Aircraft X was intercepting the final approach at 1800 feet instead of the 2800 feet assigned. Minimum Vectoring Altitude in the area was 2700 feet and intercept altitude for the ILS is 2800 feet.We were having problems on all frequencies and reception was sometimes [weak] with a lot of static on some readbacks. Main transmitters were out of service and backup frequency 132.25 was out of service because of bleed over issues on center frequencies. At the same time I was clearing Aircraft X for the approach; I was asked to do a radio check on the main transmitters on 128.65. I believe the poor reception in the frequencies and the distraction of doing a radio check caused me to miss a possible wrong readback and lose my scanning at the moment. The poor radio frequency reception on 128.65 has been an ongoing problem for months and unless something serious is done to rectify this problem I fear that a worse incident might occur.

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	1378894
Time
Date	201608
Local Time Of Day	1201-1800
Place
Locale Reference	ZSU.ARTCC
State Reference	PR
Environment
Light	Daylight
Aircraft 1
Make Model Name	Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Approach Enroute
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 3
Events
Anomaly	ATC Issue All Types Airspace Violation All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter CFTT / CFIT

ZSU controller observed an aircraft intercepting the final approach course at 1800 feet. The assigned altitude to intercept was 2800 feet and the MVA is 2700 feet.