Narrative:

I took the hand off on aircraft X. I went to work on other tasks for the sector and had my attention redirected to aircraft X upon check in. His initial transmission was garbled. I then observed the aircraft descend 100 feet below what is commonly thought to be the base altitude for the arrival. I thought maybe he went through slightly as he was descending at approximately 7500 fpm. The next radar update showed 6400 feet at which point I immediately issued a low altitude alert. No response. The subsequent hit showed 5600 feet. I again issued an abbreviated low altitude alert as I brought up the eovm (emergency obstruction video map) map and noticed aircraft X within a few hundred feet from a mountain peak. I don't recall a response the second time either; but observe the aircraft at 7100 feet on the next update.sector complexity grew; and needless to say I was shaken; as I just witnessed the closest call in my career. The absence of a response from aircraft X after the initial low altitude alert; combined with the garbled transmission on initial check in; led me to believe there was something wrong with the aircraft; and convinced me I was about to witness an aircraft crash into the mountains. After establishing separation from the terrain I proceeded to handle the aircraft as a normal arrival.clearly still shaken; I inadvertently issued 1300 feet to aircraft X instead of the normal 1600 feet to maintain until established. I corrected the mistake in a timely matter. It is important to note that we lost all radar data on aircraft X at this time too. His track completely disappeared from the radar display. I am told this is due to an anomaly with radar. Aircraft X was established on final safely and switched to tower. He ended up going missed approach. After the missed approach he wanted to join up with flight X; a flight of 3 fighters and try another approach. Apparently the join up was not done correctly. I was never trained on flight join ups; and had only had a discussion with a trainer from a facility from several years ago. At this point the complexity of the sector and the workload volume was at a level that would have proven to have been a challenge under the best of circumstances.as for why the initial incident happened? It was a mistake on the pilot's part that could have caught in a timelier manner if I had access to more reliable resources concerning the crossing restrictions outside of my airspace. The fixes are not displayed on the video map. As I said earlier; it is common thought that the base altitude on the 'arrival' is 7000 feet. I say that because I noticed the aircraft seemed lower than normal and asked the room about it. The next restriction was an at or above 7000 foot restriction and we agreed that 7000 feet should be okay there. Had the fixes been displayed; we would likely have more of a connection to their significance and it would have been more apparent; sooner; that something was wrong.the 1300 foot issuance was likely due to a transposition of information from a nearby data block. Again; the mistake was caught in time and had no real consequence. The flight join up was done incorrectly because quite frankly; I was guessing how to do it. As I said; I have zero experience or training on the matter; and I was recalling a conversation from over 11 years ago when I was a trainee at a center. I would also like to mention again that I was extremely shaken by the events. No relief was offered. Breaks weren't readily available because our staffing doesn't support it. We work combined positions that shouldn't be combined for periods of time that exceed safe operating limitations; on a regular basis. Staffing is and always has been an issue here. It affects not only the operation; but also the ability to have skilled personnel available for details such as training; airspace development; etc. We are so far behind the power curve when it comes to a safe operation because of our lack of resources to make improvements that have been identified as deficient. What results is a patchwork of antiquated procedures that haven't truly been thought out or reviewed for compliance to safety standards that are readily found elsewhere in the NAS. If this trend continues; I am convinced that these close calls will continue to become more frequent and potentially more disastrous. I was informed that the arrival is not an arrival at all. This came as a surprise to everyone because; well; it is clearly labeled 'cruzr arrival' on our references. We commonly use the phrase; 'descend via the cruzr arrival...' this is why the aircraft altitude being below the MVA was not a concern. Again; the controllers think that our base altitude is 7000. I've asked. It is a very common thought. In fact; if you ask about crossing altitudes on the 'arrival' it is often only after several minutes of research that someone is able to rattle them off. Again; flight join ups aren't typically done here. And; it is certainly not something that there has been any level of documented training on. I spoke with the quality control official at the center about how they do it there. He mentioned a declaration of marsa having to take place. I have dealt with marsa at previous facilities; but I was told that marsa is not for formation flights - those are handled differently. Interesting that two artccs would have glaring differences in how to handle the same situation.

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Original NASA ASRS Text

Title: A11 TRACON Controller reported losing communication with an aircraft which descended below the MVA before climbing and reestablishing communications. Later the aircraft requested to join up with a flight of aircraft and the Controller reported they (ATC) did not know the procedure for a flight join up.

Narrative: I took the hand off on Aircraft X. I went to work on other tasks for the sector and had my attention redirected to Aircraft X upon check in. His initial transmission was garbled. I then observed the aircraft descend 100 feet below what is commonly thought to be the base altitude for the arrival. I thought maybe he went through slightly as he was descending at approximately 7500 fpm. The next radar update showed 6400 feet at which point I immediately issued a low altitude alert. No response. The subsequent hit showed 5600 feet. I again issued an abbreviated low altitude alert as I brought up the EOVM (Emergency Obstruction Video Map) map and noticed Aircraft X within a few hundred feet from a mountain peak. I don't recall a response the second time either; but observe the aircraft at 7100 feet on the next update.Sector complexity grew; and needless to say I was shaken; as I just witnessed the closest call in my career. The absence of a response from Aircraft X after the initial low altitude alert; combined with the garbled transmission on initial check in; led me to believe there was something wrong with the aircraft; and convinced me I was about to witness an aircraft crash into the mountains. After establishing separation from the terrain I proceeded to handle the aircraft as a normal arrival.Clearly still shaken; I inadvertently issued 1300 feet to Aircraft X instead of the normal 1600 feet to maintain until established. I corrected the mistake in a timely matter. It is important to note that we lost all radar data on Aircraft X at this time too. His track completely disappeared from the radar display. I am told this is due to an anomaly with radar. Aircraft X was established on final safely and switched to tower. He ended up going missed approach. After the missed approach he wanted to join up with Flight X; a flight of 3 fighters and try another approach. Apparently the join up was not done correctly. I was never trained on flight join ups; and had only had a discussion with a trainer from a facility from several years ago. At this point the complexity of the sector and the workload volume was at a level that would have proven to have been a challenge under the best of circumstances.As for why the initial incident happened? It was a mistake on the pilot's part that could have caught in a timelier manner if I had access to more reliable resources concerning the crossing restrictions outside of my airspace. The fixes are not displayed on the video map. As I said earlier; it is common thought that the base altitude on the 'arrival' is 7000 feet. I say that because I noticed the aircraft seemed lower than normal and asked the room about it. The next restriction was an at or above 7000 foot restriction and we agreed that 7000 feet should be okay there. Had the fixes been displayed; we would likely have more of a connection to their significance and it would have been more apparent; sooner; that something was wrong.The 1300 foot issuance was likely due to a transposition of information from a nearby data block. Again; the mistake was caught in time and had no real consequence. The flight join up was done incorrectly because quite frankly; I was guessing how to do it. As I said; I have ZERO experience or training on the matter; and I was recalling a conversation from over 11 years ago when I was a trainee at a Center. I would also like to mention again that I was extremely shaken by the events. No relief was offered. Breaks weren't readily available because our staffing doesn't support it. We work combined positions that shouldn't be combined for periods of time that exceed safe operating limitations; on a regular basis. Staffing is and always has been an issue here. It affects not only the operation; but also the ability to have skilled personnel available for details such as training; airspace development; etc. We are so far behind the power curve when it comes to a safe operation because of our lack of resources to make improvements that have been identified as deficient. What results is a patchwork of antiquated procedures that haven't truly been thought out or reviewed for compliance to safety standards that are readily found elsewhere in the NAS. If this trend continues; I am convinced that these close calls will continue to become more frequent and potentially more disastrous. I was informed that the arrival is not an arrival at all. This came as a surprise to everyone because; well; it is clearly labeled 'CRUZR ARRIVAL' on our references. We commonly use the phrase; 'descend via the CRUZR arrival...' This is why the aircraft altitude being below the MVA was not a concern. Again; the controllers think that our base altitude is 7000. I've asked. It is a VERY common thought. In fact; if you ask about crossing altitudes on the 'arrival' it is often only after several minutes of research that someone is able to rattle them off. Again; flight join ups aren't typically done here. And; it is certainly not something that there has been any level of documented training on. I spoke with the Quality Control official at the Center about how they do it there. He mentioned a declaration of MARSA having to take place. I have dealt with MARSA at previous facilities; but I was told that MARSA is not for formation flights - those are handled differently. Interesting that two ARTCCs would have glaring differences in how to handle the same situation.

Data retrieved from NASA's ASRS site 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.