Controller descended aircraft below minimum vectoring altitude. Operational error.

Attributes
ACN	106235
Time
Date	198903
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : slc
State Reference	UT
Altitude	msl bound lower : 9000 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : slc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : on vectors enroute airway : slc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 103 flight time total : 10974 flight time type : 859
ASRS Report	106235
Person 2
Affiliation	company : air carrier
Function	observation : observer
Qualification	pilot : atp pilot : cfi pilot : flight engineer
ASRS Report	106029
Events
Anomaly	non adherence : far other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued new clearance other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

We were on descent from the west into the slc area under radar vectors for approach sequence to land on 16R at slc. The vector took us over the north part of the ocher mountains on an easterly heading. West of the ochers approach control cleared us to descend to 9000'. My check captain who was flying copilot said he thought that 9000' was too low and recommended a gradual descent. I made a gradual descent with visual reference to the mountains. The GPWS did not sound, however approaching 9000' east of the ochers we were told to climb immediately to 11000'. We started the climb and were then cleared back to 9000' and landing on 16R. A call to approach control after landing confirmed the original clearance to 9000' was in error. Since we were in visual conditions, this was no problem. However a normal descent to 9000' on instruments would have placed the aircraft very close to the ocher mountains. Supplemental information from acn 106029. Telephone contact with approach control on ground in slc confirmed controller error.

Original NASA ASRS Text

Title: CTLR DESCENDED ACFT BELOW MINIMUM VECTORING ALT. OPERATIONAL ERROR.

Narrative: WE WERE ON DSCNT FROM THE W INTO THE SLC AREA UNDER RADAR VECTORS FOR APCH SEQUENCE TO LAND ON 16R AT SLC. THE VECTOR TOOK US OVER THE NORTH PART OF THE OCHER MOUNTAINS ON AN EASTERLY HDG. WEST OF THE OCHERS APCH CTL CLRED US TO DSND TO 9000'. MY CHK CAPT WHO WAS FLYING COPLT SAID HE THOUGHT THAT 9000' WAS TOO LOW AND RECOMMENDED A GRADUAL DSCNT. I MADE A GRADUAL DSCNT WITH VISUAL REFERENCE TO THE MOUNTAINS. THE GPWS DID NOT SOUND, HOWEVER APCHING 9000' E OF THE OCHERS WE WERE TOLD TO CLB IMMEDIATELY TO 11000'. WE STARTED THE CLB AND WERE THEN CLRED BACK TO 9000' AND LNDG ON 16R. A CALL TO APCH CTL AFTER LNDG CONFIRMED THE ORIGINAL CLRNC TO 9000' WAS IN ERROR. SINCE WE WERE IN VISUAL CONDITIONS, THIS WAS NO PROB. HOWEVER A NORMAL DSCNT TO 9000' ON INSTRUMENTS WOULD HAVE PLACED THE ACFT VERY CLOSE TO THE OCHER MOUNTAINS. SUPPLEMENTAL INFO FROM ACN 106029. TELEPHONE CONTACT WITH APCH CTL ON GND IN SLC CONFIRMED CTLR ERROR.

Data retrieved from NASA's ASRS site as of August 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.