Approach controller descends an IFR SF34 below the MVA altitude due to sequencing and close spacing ...

Attributes
ACN	388108
Time
Date	199711
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : pvd
State Reference	RI
Altitude	msl bound lower : 1500 msl bound upper : 1800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : pvd
Operator	common carrier : air carrier
Make Model Name	SF 340A
Operating Under FAR Part	Part 121
Flight Phase	landing other
Route In Use	approach : visual enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Helicopter
Operating Under FAR Part	Part 91
Flight Phase	landing other
Flight Plan	VFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller military : 4 controller non radar : 20 controller radar : 10
ASRS Report	388108
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : published procedure other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

The SF34 was being vectored on a right downwind for the visual runway 23 approach. VFR helicopter traffic was 2 mi off his right and I had planned to follow the helicopter with the SF34. The MVA in the area is 1800 ft (1 1/2 mi to the east of the SF34 the MVA drops to 1500 ft). The SF34 was turned to a 90 degree heading for his base to final turn. Concurrently a C172 (VFR) at 2200 ft was preceding inbound on the ILS runway 23 localizer. The C172 was not cleared for the approach, was instructed to make a left 360 degree turn at the marker so as to fall in behind faster traffic behind. The cessna began his turn inside the marker (1/2 - 3/4 mi) which made me descend the SF34 to 1500 ft to avoid the C172. In reflection I believe that the SF34 should have been first instead of the helicopter which would have made the MVA line a moot point and the overall operation a lot smoother.

Original NASA ASRS Text

Title: APCH CTLR DSNDS AN IFR SF34 BELOW THE MVA ALT DUE TO SEQUENCING AND CLOSE SPACING ON FINAL APCH.

Narrative: THE SF34 WAS BEING VECTORED ON A R DOWNWIND FOR THE VISUAL RWY 23 APCH. VFR HELI TFC WAS 2 MI OFF HIS R AND I HAD PLANNED TO FOLLOW THE HELI WITH THE SF34. THE MVA IN THE AREA IS 1800 FT (1 1/2 MI TO THE E OF THE SF34 THE MVA DROPS TO 1500 FT). THE SF34 WAS TURNED TO A 90 DEG HDG FOR HIS BASE TO FINAL TURN. CONCURRENTLY A C172 (VFR) AT 2200 FT WAS PRECEDING INBOUND ON THE ILS RWY 23 LOC. THE C172 WAS NOT CLRED FOR THE APCH, WAS INSTRUCTED TO MAKE A L 360 DEG TURN AT THE MARKER SO AS TO FALL IN BEHIND FASTER TFC BEHIND. THE CESSNA BEGAN HIS TURN INSIDE THE MARKER (1/2 - 3/4 MI) WHICH MADE ME DSND THE SF34 TO 1500 FT TO AVOID THE C172. IN REFLECTION I BELIEVE THAT THE SF34 SHOULD HAVE BEEN FIRST INSTEAD OF THE HELI WHICH WOULD HAVE MADE THE MVA LINE A MOOT POINT AND THE OVERALL OP A LOT SMOOTHER.

Data retrieved from NASA's ASRS site as of July 2007 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.

Approach controller descends an IFR SF34 below the MVA altitude due to sequencing and close spacing on final approach.