Small transport X assigned altitude below MVA. System error.

Attributes
ACN	166584
Time
Date	199012
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : okc
State Reference	OK
Altitude	msl bound lower : 3000 msl bound upper : 4000
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : okc
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other cruise other descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller military : 4 controller non radar : 8 controller radar : 20
ASRS Report	166584
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument
Events
Anomaly	non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Small transport X had made a planned missed approach (assigned heading 080 degrees to maintain 3000'), and was being vectored for a VOR runway 17 approach to the will rogers airport. I vectored small transport X into airspace in which the minimum vectoring altitude is 3700' at an assigned altitude of 3000'. I was not aware small transport X was still at 3000' until I cleared him for the approach to maintain 4000' until established on the final approach course and he said he was still at 3000' and asked if he was to climb to 4000'. I climbed small transport X to 4000' and reclred him for the approach. At that time the aircraft's mode C indicated 3300'. At no time did the C/a and/or low altitude alert system sound an alarm, or flash low altitude alert in the ARTS data block. At the time of the incident, I was working 3 positions combined. They were northwest radar, southwest radar and final radar positions. I believe there are 3 actions that can help prevent a recurrence of this situation. First, radar operating positions should be decombined so controllers are less busy and can devote more attention to each aircraft. Second, the C/a and/or low altitude alert system must be operational and give more timely alerts. Third, the missed approach should have an assigned altitude of 4000' instead of 3000' if the planned route will take the aircraft into airspace with a minimum vectoring altitude that is grater than 3000'.

Original NASA ASRS Text

Title: SMT X ASSIGNED ALT BELOW MVA. SYSTEM ERROR.

Narrative: SMT X HAD MADE A PLANNED MISSED APCH (ASSIGNED HDG 080 DEGS TO MAINTAIN 3000'), AND WAS BEING VECTORED FOR A VOR RWY 17 APCH TO THE WILL ROGERS ARPT. I VECTORED SMT X INTO AIRSPACE IN WHICH THE MINIMUM VECTORING ALT IS 3700' AT AN ASSIGNED ALT OF 3000'. I WAS NOT AWARE SMT X WAS STILL AT 3000' UNTIL I CLRED HIM FOR THE APCH TO MAINTAIN 4000' UNTIL ESTABLISHED ON THE FINAL APCH COURSE AND HE SAID HE WAS STILL AT 3000' AND ASKED IF HE WAS TO CLB TO 4000'. I CLBED SMT X TO 4000' AND RECLRED HIM FOR THE APCH. AT THAT TIME THE ACFT'S MODE C INDICATED 3300'. AT NO TIME DID THE C/A AND/OR LOW ALT ALERT SYS SOUND AN ALARM, OR FLASH LOW ALT ALERT IN THE ARTS DATA BLOCK. AT THE TIME OF THE INCIDENT, I WAS WORKING 3 POSITIONS COMBINED. THEY WERE NW RADAR, SW RADAR AND FINAL RADAR POSITIONS. I BELIEVE THERE ARE 3 ACTIONS THAT CAN HELP PREVENT A RECURRENCE OF THIS SITUATION. FIRST, RADAR OPERATING POSITIONS SHOULD BE DECOMBINED SO CTLRS ARE LESS BUSY AND CAN DEVOTE MORE ATTN TO EACH ACFT. SECOND, THE C/A AND/OR LOW ALT ALERT SYS MUST BE OPERATIONAL AND GIVE MORE TIMELY ALERTS. THIRD, THE MISSED APCH SHOULD HAVE AN ASSIGNED ALT OF 4000' INSTEAD OF 3000' IF THE PLANNED RTE WILL TAKE THE ACFT INTO AIRSPACE WITH A MINIMUM VECTORING ALT THAT IS GRATER THAN 3000'.

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.