Why a non precision approach is the most dangerous IFR flight segment

I believe non-precision approaches are the most difficult and dangerous segment of a flight, especially at night to an untowered airport with a short runway. I will talk about A/P (autopilot) coupled approaches only here, we already know how to hand fly them. For example look at KHTO RNAV 10. The final segment is just 2.4nm from threshold and starts 805' agl. If weather is to minimums as is frequent (evening ocean haze) you must dive aggressively at LAZYE to the MDA or you quickly find yourself looking straight down at runway lights, still 500' agl.

Hand-flying vs autopilot coupled non-precision approaches

I believe autopilot coupled approaches are more difficult than hand flown approaches because you should not start using automation until you've mastered hand flying. For this reason, they are also more professional and safer if done correctly. And for the same reason, they can be extremely dangerous if used by inexperienced pilot as a crutch. Only use automation if you are current in your aircraft and an expert in your avionics. Otherwise it is safer to hand fly the approach, less can go wrong and if it does, you will initiate go-around sooner, and be ahead of the plane during the go-around.

How to fly a non-precision approach in an Avidyne SR22 like a pro

This is the technique I developed. I'll focus on SR22 specific bits here, not generic approach techniques like 5T's and briefing the plate.

Initial Configuration before FAF

1. Plane starts in level flight 20” MP 100kts 50% flaps approaching IAF
2. A/P is in NAV APP and VS mode, VS bug is set to 0.
3. Alt bug is set to next segment altitude.
4. Garmin 430 is on default nav page, shows countdown to next waypoint. Out loud say time remaining, ie: “35 seconds”.

Flying the Segments

1. When your GPS next-waypoint-countdown reaches 0 seconds, simultaneously twist VS to -800fpm and reduce throttle to 12” MP. ALWAYS do these together.
2. Monitor altitude (and purple altitude bug). When within 100 feet of target altitude, call out "100 feet to go" and simultaneously set AP to ALT+VS (altitude intercept) and throttle to 20” MP. ALWAYS do these together. 
3. When leveled off, twist alt bug to next segment altitude and engage VS mode again. VS bug is already at 0.
4. Say out-loud time remaining to next waypoint and monitor timer. Go to step 1.

Tips:

• I keep my fingers over the ALT+VS button during the descent.
• I call out "100 feet to go" at each segment

Never, ever use altitude intercept during approach

I believe using the autopilot incorrectly in non-prec approaches can be extremely dangerous and has been fatal for some unlucky pilots and their passengers. A/P altitude intercept should never be used between segments. Why? Because a dangerous dependency combination of automation (pitch control) and manual control input (thrust) is created. A short distraction can lead to a fatal autopilot stall. If the plane levels with 50% flaps at 12" MP and the pilot is distracted and doesn't bring up MP to 20" the plane will stall. You're close to the ground in IMC, possibly too low for CAPS and it's probably gusty/stormy so windsheer can induce stall sooner than usual. And you must first disengage A/P to even begin stall recovery.  Night time, 400' AGL, IMC, A/P on, think you can recover from a stall?

**Another reason to avoid AP altitude intercept is the level-off is too gradual, you will get -300fpm, not -800fpm.

This is why I use the VS mode and only engage ALT+VS to level off at target altitude. I am  commanding the aircraft to level by physically pushing AP buttons, and at the same time I change power setting. I always do these together. It is a flow, a habit. This direct commanding is very different from monitoring the A/P for "leveling off", which is very indirect and easier to miss.

The downside is you could blow through altitude, but, from day 1 of flying our scan monitors the "6-pack instruments" so altitude is far less likely to be missed. And I'd rather blow through altitude by 100' on non precision approach then find myself looking at 70kias in horror perfectly leveled 400' above the ground having to shove black knob full forward.

Why a non-precision approach is more dangerous than ILS

Even a simple 3-fix approach at HTO will require at least SEVEN configuration changes - each waypoint requires a descent (1 change) and level-off (2nd change). Some pilots fly non-precision approaches as a "stabilized approach" with constant descent rate, but when ceiling is to minimums, this will not work, you will not see the runway in time. The "dive and level" method is unfortunately necessary.

Compare that to an ILS - it's just 1 configuration change when glide slope is captured.

VIsualize your VDP during the brief

Look back at the HTO approach.
Q: If you spot the runway just before the MAP, can you land?
A: NO. You are 500' agl above the approach end of a 4255' runway doing 100kts. You will definitely overrun the runway if you try to land. 
The subtle reality is If a VDP was depicted it would come long before the MAP, at least 1.2nm. 1.2nm before MAP is your real "last chance to land" opportunity.  Figure this out in your brief.
** Note I would NOT recommend flying any slower than 100kias on A/P, the buffer is important for safety. I think if you're hand flying it's ok to go a little slower.

I visualize my VDP as part of the brief. "If I do not see runway lights 1.2nm from threshold, I will commit to going missed at the MAP". It takes about 45s to fly the last 1.2nm, you can relax and prepare mentally for a safe missed approach. I mentally visualize a VASI on the ground and pretend it's showing "above glide slope" when flying to minimums, this removes temptation for me to try to land late.

Even if you fly it perfectly, landing is stlll very unstabilized

If you safely and successfully dive to the MDA after LAZYE and spot the VASI on glide slope 1.2nm before the MAP, you're now in a very unstabilized attitude: 20kts over your normal 80kts approach speed on very short final with only 50% flaps. You must now:

1. Disengage A/P
2. 100% flaps
3. Chop throttle

Wow, that looks like acrobatics more than a stabilized landing. But it's necessary to slow the plane to land. And you're doing this in low visibility conditions on a short runway with dim approach lighting. Are you up for this? If not, don't even try this approach.

Visibility is the real killer

Without looking, can you tell me what visibility minimums for the approach are? If not, shame on you. Ceilings are important (MDA is 445' AGL), but as a high time Part 135 pilot told me, visibility is the real killer. Minimums are 1sm here, or 5280'. Runway lenght is 4255'. Therefore, 1025' before the threshold, you must be able to see the departure end. On a foggy day with low ceilings, you cannot legally shoot this approach.

Going Missed

The attitude indicator is your primary instrument when going missed. Pitch to 7.5', throttle full forward, and concentrate on the AI until you are 1000' agl.

Danger of autopilot stall is very real

Good pilots don't stall planes, but autopilots do. Picture this situation: You're in IMC, it's gusty, you're not flying the plane so you don't feel control inputs at all, it's dark, you're wearing a headset so don't hear any wind noise, you're watching the next waypoint counter count down.. Everything seems fine, and suddenly you hear the stall horn. The normal visual, audio, and physical queues of stall onset are gone in this scenario. The only hint you'll have is bleeding IAS. But when flying A/P, is IAS a part of your regular scan, or are you more focused on altitude, heading, and GPS configuration? Do not take this lightly. Pilots make mistakes, they always will. The best thing to do is to accept this and alter your routine so that mistakes aren't fatal.

Briefing CAPS on approach

We are taught to brief CAPS on takeoff, but what about prior to an approach? The MDA for non precision approaches is generally high enough for CAPS use. Make this a part of your briefing,

Final Words

I hope i scared you enough to increase your personal minimums for non precision approaches. Until you have 100s of hours in the type and are highly confident in not only hand flying but also deeply understand all the automation in your aircraft, do not fly non precision approaches to minimums at small airports. The stakes are really high. Go shoot an ILS at a bigger airport and get a $50 holiday inn.