Narrative:

Russellville, ar, is a mountainous area involving a number of different mia's in a relatively small area. These mia's are depicted for controllers on charts located at each sector. Unfortunately, those charts contain a min of information making it difficult (at best) for the controller to accurately determine the boundaries for the various mia's. As a result, the controller is often forced to give a higher altitude (sometimes as much as 600 ft), since the exact position of the mia change cannot be determined. This provides a disservice to the public, and could cause an accident in the event the wrong mia were given. At memphis center, a test was run in which a video display of the chart was provided on the scope. Unfortunately, the sector chosen for the test had very few mia's, each having minor altitude differences from the other. As a result, it was concluded that the video map was unnecessary. On the contrary, providing maximum safety to the public by using a filter key select video map of mia's is a necessity. In this case, an aircraft was given 3700 ft to maintain until IAF instead of 3400 ft due to MSAW resolution. This caused the aircraft to execute a procedure turn before breaking out for a visual. The same thing occurred with another small aircraft where according to the mia chart, 3400 ft should have been good. Instead, a MSAW alert was activated by small aircraft before any altitude was violated. Either the chart was wrong or the programmed MSAW distance was wrong. In this case it was not a problem, however, around harrison, ar, where aircraft are nonradar, controllers can only guess as to mia boundaries without the benefit of MSAW. The potential for an accident there, as other places, is great.

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Original NASA ASRS Text

Title: CTLR RECEIVED MSAW WARNING AFTER DSNDING SMA TO MIN IFR ALT. SITUATION: NO VIDEO MAP OVERLAY SHOWING MIN IFR ALT IN ARTCC RADAR SECTORS.

Narrative: RUSSELLVILLE, AR, IS A MOUNTAINOUS AREA INVOLVING A NUMBER OF DIFFERENT MIA'S IN A RELATIVELY SMALL AREA. THESE MIA'S ARE DEPICTED FOR CTLRS ON CHARTS LOCATED AT EACH SECTOR. UNFORTUNATELY, THOSE CHARTS CONTAIN A MIN OF INFO MAKING IT DIFFICULT (AT BEST) FOR THE CTLR TO ACCURATELY DETERMINE THE BOUNDARIES FOR THE VARIOUS MIA'S. AS A RESULT, THE CTLR IS OFTEN FORCED TO GIVE A HIGHER ALT (SOMETIMES AS MUCH AS 600 FT), SINCE THE EXACT POS OF THE MIA CHANGE CANNOT BE DETERMINED. THIS PROVIDES A DISSERVICE TO THE PUBLIC, AND COULD CAUSE AN ACCIDENT IN THE EVENT THE WRONG MIA WERE GIVEN. AT MEMPHIS CENTER, A TEST WAS RUN IN WHICH A VIDEO DISPLAY OF THE CHART WAS PROVIDED ON THE SCOPE. UNFORTUNATELY, THE SECTOR CHOSEN FOR THE TEST HAD VERY FEW MIA'S, EACH HAVING MINOR ALT DIFFERENCES FROM THE OTHER. AS A RESULT, IT WAS CONCLUDED THAT THE VIDEO MAP WAS UNNECESSARY. ON THE CONTRARY, PROVIDING MAX SAFETY TO THE PUBLIC BY USING A FILTER KEY SELECT VIDEO MAP OF MIA'S IS A NECESSITY. IN THIS CASE, AN ACFT WAS GIVEN 3700 FT TO MAINTAIN UNTIL IAF INSTEAD OF 3400 FT DUE TO MSAW RESOLUTION. THIS CAUSED THE ACFT TO EXECUTE A PROC TURN BEFORE BREAKING OUT FOR A VISUAL. THE SAME THING OCCURRED WITH ANOTHER SMA WHERE ACCORDING TO THE MIA CHART, 3400 FT SHOULD HAVE BEEN GOOD. INSTEAD, A MSAW ALERT WAS ACTIVATED BY SMA BEFORE ANY ALT WAS VIOLATED. EITHER THE CHART WAS WRONG OR THE PROGRAMMED MSAW DISTANCE WAS WRONG. IN THIS CASE IT WAS NOT A PROBLEM, HOWEVER, AROUND HARRISON, AR, WHERE ACFT ARE NONRADAR, CTLRS CAN ONLY GUESS AS TO MIA BOUNDARIES WITHOUT THE BENEFIT OF MSAW. THE POTENTIAL FOR AN ACCIDENT THERE, AS OTHER PLACES, IS GREAT.

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.