TRACON controller described a below MVA event when an IFR aircraft was issued the latitude of traffi...

Narrative:

Aircraft X; wad descended to 3;000 ft and was slowed to 170 KTS and issued traffic to follow at 12 o'clock and 4 miles a B737 descending out of 2;000 ft; the pilot of aircraft X readback; 'traffic in sight descending to 2;000 ft.' I held back the visual approach clearance knowing the aircraft had not passed the obstruction ahead who's MVA was 3;000 ft. I observed the aircraft descending through 2;300 ft and issued a low altitude alert and an immediate climb to 3;000 ft. The aircraft saw the obstruction and climbed back up to 3;000 ft. I would not have told him the altitude of the traffic; if I thought it would have confused the pilot into thinking that was his altitude.

Original NASA ASRS Text

Title: TRACON Controller described a below MVA event when an IFR aircraft was issued the latitude of traffic and interpreted same as an assigned altitude starting a descent.

Narrative: Aircraft X; wad descended to 3;000 FT and was slowed to 170 KTS and issued traffic to follow at 12 o'clock and 4 miles a B737 descending out of 2;000 FT; the pilot of Aircraft X readback; 'traffic in sight descending to 2;000 FT.' I held back the visual approach clearance knowing the aircraft had not passed the obstruction ahead who's MVA was 3;000 FT. I observed the aircraft descending through 2;300 FT and issued a low altitude alert and an immediate climb to 3;000 FT. The aircraft saw the obstruction and climbed back up to 3;000 FT. I would not have told him the altitude of the traffic; if I thought it would have confused the pilot into thinking that was his altitude.

Data retrieved from NASA's ASRS site as of July 2013 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	1115794
Time
Date	201309
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	Citation V/Ultra/Encore (C560)
Flight Phase	Cruise
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Approach Departure
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance

TRACON controller described a below MVA event when an IFR aircraft was issued the latitude of traffic and interpreted same as an assigned altitude starting a descent.