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Sct controller described an unauthorized descent below MVA; noting the ATC MSAW equipment did not alarm.
| Attributes | |
| ACN | 934155 |
| Time | |
| Date | 201102 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | SCT.TRACON |
| State Reference | CA |
| Aircraft 1 | |
| Make Model Name | MD-80 Series (DC-9-80) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Initial Approach |
| Route In Use | Vectors |
| Flight Plan | IFR |
| Person 1 | |
| Function | Approach |
| Qualification | Air Traffic Control Fully Certified |
| Events | |
| Anomaly | ATC Issue All Types Deviation - Altitude Overshoot Deviation - Procedural Clearance Inflight Event / Encounter CFTT / CFIT |
Narrative:
I was working sder and a MD80 checked on my frequency from over jli established on the LINDI2 arrival. I initially told him to descend via the arrival. I later told him to fly present heading and maintain 8;000 for sequence. I intended to turn another air carrier in ahead of him from the north downwind and needed the additional spacing. I then descended the MD80 to 6;000 and the pilot read that back. I turned the MD80 to a heading of 250 to intercept the final and he read that back. I then slowed him to 210 KTS for spacing with the other air carrier. I then focused on turning the other air carrier base ahead of the MD80. I guess it was at this point that I failed to notice the MD80 descending below his assigned altitude of 6;000. I cleared the other air carrier for the approach and returned my attention to the MD80. It was then that I noticed the MD80 at 4;100 in a 4;800 MVA area. He was only a mile from entering a 3;800 MVA area so I gave him his approach clearance. I asked him if he had descended on his own on the approach and he replied in the affirmative. Recommendation; low altitude alert never triggered for this event. I would suggest finding out why. I will be more attentive to aircraft altitudes.
Original NASA ASRS Text
Title: SCT Controller described an unauthorized descent below MVA; noting the ATC MSAW equipment did not alarm.
Narrative: I was working SDER and a MD80 checked on my frequency from over JLI established on the LINDI2 arrival. I initially told him to descend via the arrival. I later told him to fly present heading and maintain 8;000 for sequence. I intended to turn another air carrier in ahead of him from the north downwind and needed the additional spacing. I then descended the MD80 to 6;000 and the pilot read that back. I turned the MD80 to a heading of 250 to intercept the final and he read that back. I then slowed him to 210 KTS for spacing with the other air carrier. I then focused on turning the other air carrier base ahead of the MD80. I guess it was at this point that I failed to notice the MD80 descending below his assigned altitude of 6;000. I cleared the other air carrier for the approach and returned my attention to the MD80. It was then that I noticed the MD80 at 4;100 in a 4;800 MVA area. He was only a mile from entering a 3;800 MVA area so I gave him his approach clearance. I asked him if he had descended on his own on the approach and he replied in the affirmative. Recommendation; Low Altitude Alert never triggered for this event. I would suggest finding out why. I will be more attentive to aircraft altitudes.
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.