Narrative:

I was training on the radar position at ZFW donie low sector. This sector's altitude stratum is 000-FL230 and is primarily the low altitude sequencing sector to aircraft inbound to dfw and surrounding satellite airports. It contains roughly 8 uncontrolled airports; three of which have published instrument approaches. The volume was average but radar/nexrad weather depictions on the radar scope made normal traffic more complex. A flight was inbound to one of these airports and was issued the radar derived weather and given a clearance to deviate around it after all necessary coordination had been accomplished. The aircraft was asked what type of approach he was requesting and upon receiving that information; he was given a descent to 3000 feet until established and cleared for an RNAV GPS runway 18 psn. After scanning the sector and communicating control instructions to other aircraft my instructor and I noticed that aircraft X was below the MEA. My instructor seized the frequencies and questioned him if he was established on the arrival and given a response of no. The aircraft said he was having some problems with his GPS and was trying to correct it when he was issued a low altitude alert and told to climb to 3000 immediately. Recommendation; it is my understanding that MSAW alerts won't work in the near vicinity of an airport if an aircraft is inbound to that airport. An effective scan potentially saved a flight from inadvertently striking the ground. Perhaps enabling emsaw alerts and allowing controllers to suppress them would be advantageous when the volume and complexity of a session doesn't allow a scan rate that could prevent an accident below the MEA/MVA.

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Original NASA ASRS Text

Title: ZFW controller described low altitude alert event when aircraft conducting a RNAV/GPS Runway 18 approach to PSN was observed starting a descent below published altitude; reporter questioning the absence of a MSAW alert.

Narrative: I was training on the radar position at ZFW Donie Low sector. This sector's altitude stratum is 000-FL230 and is primarily the low altitude sequencing sector to aircraft inbound to DFW and surrounding satellite airports. It contains roughly 8 uncontrolled airports; three of which have published instrument approaches. The volume was average but RADAR/NEXRAD weather depictions on the RADAR scope made normal traffic more complex. A flight was inbound to one of these airports and was issued the RADAR derived weather and given a clearance to deviate around it after all necessary coordination had been accomplished. The aircraft was asked what type of approach he was requesting and upon receiving that information; he was given a descent to 3000 feet until established and cleared for an RNAV GPS Runway 18 PSN. After scanning the sector and communicating control instructions to other aircraft my instructor and I noticed that Aircraft X was below the MEA. My instructor seized the frequencies and questioned him if he was established on the arrival and given a response of no. The aircraft said he was having some problems with his GPS and was trying to correct it when he was issued a low altitude alert and told to climb to 3000 immediately. Recommendation; it is my understanding that MSAW alerts won't work in the near vicinity of an airport if an aircraft is inbound to that airport. An effective scan potentially saved a flight from inadvertently striking the ground. Perhaps enabling EMSAW alerts and allowing controllers to suppress them would be advantageous when the volume and complexity of a session doesn't allow a scan rate that could prevent an accident below the MEA/MVA.

Data retrieved from NASA's ASRS site as of April 2012 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.