Okay, here was my worst close call-
Day to Night to NVG DLQ/RLQs about 50nm off the coast of JAX. 0% illumination (read as- dark as a manatees asshole at night during an eclipse, while locked in a photo lab)
Days went OK. Nights were underway, the pinkie time had been burned up with an OIC and the PXO. I was the HAC, riding left seat in PW-423, an old as shit block 0 SH-60B. It's now "f'in dark" and I have a PQM less than a month out of the RAG in the right seat. He's doing well, but he's still in the "HOLY SHIT I can't belive we do this AT NIGHT" mode. I believe later in the night was to be his NVG initial qual, but we were getting his unaided night qual first.
We were 200' on downwind, I had him do a couple 400' approaches, and now was introducing him to the 200' alternate approach. For those who don't speak Small Boy, you drive in at 200' to hit the 1/2 mile gate at 50 knots, and decel from there to cross the deck edge with 5ish knots closure.
As we are at about the 90 1 mile astern, I feel a bump in the aircraft. MASTER CAUTION and AFCS caution lights come on. I check the "cubes" and pretty much all modes are offline. I attempt reset, no joy. 5 seconds later, from the nugget, "SHIT I just lost the GYRO". I grab the controls and get on mine. Pilot's AI is tumbling, and eventually locks up jumping +/- 20 degrees in pitch.
ATO gyro tumbles, settles out on essentially knife edge, and +/- 30 degrees roll oscillations beynod that. Both turn needles pegged, an for those who haven't been in a 60B, there is NO BACKUP GYRO. None.
We are now passing through the 45, about .8 astern. I've been turning via seat of pants. I have no attiude reference save the ship. The LSO had called a more or less standard "Green Deck for 1 and 2, Pitch 2 Roll 5" as this was going on. I was using the ship's stern light and masthead light as a "vertical horizon" knowing that it was within 5 degrees of verical to keep the helo upright.
I had a quick second to declare the emergency to the LSO, and the AW came up with probably the most rapid-fire closure/altitude calls I have ever heard in my career. Landed, LSO locked us into the RSD then I started to shake a bit.
If those gyros had tumbled 10 seconds earlier, I would not be here today.
There was a pair of fatal class A's right before this, and they started looking at the NSIUs on the 60s, and it turns out the boxes had a failure mode that LMCO and Sikorsky said was "impossible" that was, in fact possible.