One of my old captains once said, "All God's pilots got torches." Hopefully, all God's pilots can get at them when the aircraft is in an extreme unusual attitude....and also find that they work.
The following is something I feel very strongly about...since the 747 crash at Stansted really.
When I was a new ppruner, I made some comment about turn and slip indicators and the fact that they are such a simple piece of kit...and even while on batteries, could output to a warning system if on full scale deflection. Why did they get taken out of the standard panel I asked. I got flamed.
Much of the flaming was about posting my meanderings on R&N, and one soul piped up and said that there was little chance of controlling an aircraft on such an instrument. It wasn't put so politely.
Having done dozens of approaches and occasionally full blind landings on limited panel–monitored by a test pilot in the RHS I hasten to add–I know that this modest instrument would have saved the Viscount. That particular captain loved such challenges and with power on just one tied gyro he would, I am sure, have pulled off a cloud-break.
This little instrument can take any amount of chaotic input, and still be as good as before any upset. Some of the standby horizons, while on back-up power are not as solid as they may appear.
I have had two major losses of instruments in my career, plus two across-the-board black screen scenarios. Yep, the standby horizon worked in these latter cases, but the power came from the heart of a rather badly designed electrical system.
As any glider pilot will know, there is an horizon that is so small that you could put it in your shirt pocket. It's strange to think that such an item plus a mobile phone, could save hundreds of lives.