A Center Controller and their trainee reported an aircraft they took a hand off on deviated from course and descended below the Minimum Vectoring Altitude while still in the previous sector airspace while returning to the departure airport due to an aircraft mechanical problem.
Synopsis
A Center Controller and their trainee reported an aircraft they took a hand off on deviated from course and descended below the Minimum Vectoring Altitude while still in the previous sector airspace while returning to the departure airport due to an aircraft mechanical problem.
Narrative
Aircraft X was climbing from 15000 ft. to 23000 ft. when they checked on; still outside our airspace. About 1 minute later; they said they were returning to ZZZ to land. The trainee answered and said; 'do you need any assistance'; to which there was no reply. Shortly after; the aircraft said they were having control issues and [requested priority handling]. We were trying to communicate when Center sector to get approval to turn the aircraft back before we officially cleared them back. The aircraft turned on his own and began descending. The D side training team was coordinating with Center. The pilots were clearly busy and were not responding until they were able. The altitude 6000 ft. was assigned and the pilot read that back. They asked for vectors and a 150 heading was assigned; which they also read back. Later a 180 heading was assigned; and then we asked for fuel remaining. I noticed the aircraft was descending below 6000 ft. and asked the trainee to verify the altitude; but then decided to issue a low altitude alert. I told the aircraft to stop their descent because of minimum terrain and they replied that they were trying. We then switched the aircraft to ZZZ Approach.As a Trainer; I thought of clearing the aircraft back to ZZZ right away; but we never issued it. Once the aircraft turned around and began descending so quickly; on falcon it appears at one point the descent rate was over 5000 FPM; my focus was on coordination and getting the heading and altitude assigned. I thought about the clearance again; but we were trying to get fuel and the radio coverage was getting bad and the pilots were too busy to answer; so the clearance to the airport just never happened; but it was on an assigned heading. We could not flash the data block at Center; or at least the trainee claims he tried to flash it a couple times and it never worked. I didn't notice because the MSAW warning was flashing and I didn't see that it wasn't flashing to anybody. Therefore; the data block never got flashed to ZZZ Approach. I'm not sure if we violated them or not. We do not have the ability to talk to that Approach Control. The D side team asked Center sector if they could pass on all the info to ZZZ Approach; they said they would; and they said we could switch the aircraft to approach control directly. This was just a very weird circumstance that the aircraft never actually came into our airspace; and the most immediate thing was to get the aircraft on the heading and trying to assist as best as possible. We had no way to speak to the Approach Control to which they were returning; but there was not a good reason to switch them back to Center sector when the aircraft was descending so quickly. The best thing was to get the aircraft talking with Approach Control so they could get the best response at the airport ready for them.
Second reporter narrative
I was training on the Center Area 2 low radar sectors. Aircraft X was climbing out of 15;000 for 23;000 ft. coming from the south not in my airspace yet. Aircraft X originally was going to ZZZ1. Passing 15;500 ft. the pilot stated they were going to ZZZ which was south of their position. I rogered the pilot and asked if they needed assistance. I did not clear Aircraft X yet because they were not in my airspace and had to coordinate with the sector they were coming from they were turning around to land south of their position. As my D-side training team was coordinating with Center sector I tried to get more information from the pilot as they started descending on their own. I asked the nature of the [event] and fuel remaining. The pilot said flight controls and 2;800 lbs. Center approved down to 6;000 for Aircraft X and I issued that altitude to the aircraft. I typed their new destination into the flight plan but did not clear Aircraft X to ZZZ. Aircraft X requested headings for Runway XX and was issued heading 150. Aircraft X descended through 6;000 ft. and my instructor issued a low altitude alert and the MVA in the area of 5;200 ft. We were unable to flash Aircraft X to Center sector. I think that is because they never entered my airspace but not sure. We asked Center sector to coordinate with ZZZ Approach and put Aircraft X directly on ZZZ Approach's frequency. Nothing could be done to prevent the [situation] but we could have cleared Aircraft X to ZZZ airport and I should have issued the low altitude alert when the aircraft descended below 6;000 ft. with a 5;200 MVA.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.