PilotEdge Forums

I'm curious what other pilots here think.
I fly a Cardinal fixed gear in the real world. I'm working on my instrument rating and am considering two different scenarios for precision approaches

Scenario 1: As described in Peter Dougan's book, I can fly my approach level with 17"MP, 10deg flaps and approach descent at 13" MP all at 90MPH (my plane is mph AS). The advantage as Dougan points out is that that configuration (flaps and AS) is exactly my climb out config if I need to go missed. The other advantage is that 17" MP is also my cruise descent power setting. So descending from cruise at 135 mph and entering approach level at 90 mph only requires me to hold the nose up and re-trim for 90mph. Once inside the FAF I simply set MP to 13" and fly the glide path. The disadvantage is that I need to bring in 20deg flaps right before touch down which causes a bit of flaring. I've also read that it's poor practice to make any config changes inside of FAF.

Scenario 2: descend from cruise at 17" MP and 135mph. Then reset power for 20" and 20deg flaps for approach level at 80 mph. Then set MP to 15" for approach descent at 80mph inside the FAF. The advantage is that I would that there would not normally be any config changes inside of the FAF. Also an advantage of flying slower approach and lower stall speed. However on missed I would need to add full power, pull out flaps to 10deg, and re-trim for 90mph climb.

So, in one case there is more to do inside of FAF (but only if I have the runway environment identified and it's clear I'm landing). The other case, nothing to do inside FAF to touchdown, but more to do on a missed.
I'd like to hear opinions about which is best and why.

Thanks

80 mph is too slow I'd say. I'd consider using something closer to 100 mph. That puts you more comfortably on the front end of the power curve and you won't spend forever on final. It also has the advantage of being about 90 knots which makes quick descent/timing calculations easier (1.5 nm/minute). Whether or not to use some flaps can depend on the severity of the pitch change on the first notch, the pitch attitude that results at MDA (is it difficult to see over the nose with flaps up), engine cooling concerns from the lower power setting without, or personal preference. Either way you'll likely be adding more flaps once you commit to landing and you should practice the pitch, power, and trim changes involved in that transition. That said I've never flown a 177.

I can't speak specifically for the Cardinal, but to add one perspective, my instrument approaches in a Cherokee 180 are done at 100mph in a clean configuration. The maximum flap extension speed is 115mph, so the flaps can be deployed at any point during the approach. I've found that there is more than enough time to deploy the flaps and decelerate, even at 200AGL on an ILS approach. If I have to go missed, I simply put in full throttle and the plane will climb near its Vy speed.

I have a very different take on flying approaches. This is something that resulted in a 3 hour discussion with Tom Turner from the head of the Bonanza society one night in Nashua, NH while he attended the IFR Bootcamp. My take is that when you're doing real world flying, it's exceedingly rare to have calm wind conditions, or winds that are static as you start out at 3000ft and eventually reach decision height at 200ft. That, and there are factors such as turbulence and traffic. For example, I've flown ILS approaches at JFK at 170kias+ all the way to a 5 mile final.

As a result of all those factors, I don't shoot for a particular speed or power setting on an approach...I know that sounds patently ridiculous, but I fly whatever speed is appropriate for the conditions, and I apply a mentality of "less power" or "more power" based on whether I need to add or remove energy from the equation. It's very fluid but it has served me well. Generally speaking, I fly approaches faster than what would be considered standard. I argue that it's no harder to track a glideslope at 160kts than it is to do it at 80kts. It does mean, though, that I'm done with the approach in half the time, which means I spend less time shooting the approach.

Being trimmed and configured for the missed is nice, but is not a requirement for me. I don't do Vy climbs (for cooling) and am absolutely going to clean up the flaps and gear on the missed anyway, so I'm already committed to a series of configuration changes when the time comes.

What I like about this philosophy is that it allows me to alter the plan based on conditions whilst remaining in total comfort. Being wedded to speeds and power settings means that when a situation occurs which requires a deviation from those numbers, you might be out of your comfort zone, and not as proficient with simply flying the profile based on real-time data, as opposed to simply dialing in a power/speed.

This is also the reason that I'm obsessed with TRK, DTK and XTK when flying an approach (track, desired track and cross-track error). In cases where you have a 40kt crosswind from one side, shearing to a 10kt crosswind from the other side, all within 4000ft, the heading indicator is almost useless. The heading you were flying 300ft ago won't work because the xwind component has changed yet again.

I think this all start happening when I test flew 22 radio controlled planes for my neighbor over the course of a few years back in California. I got used to the notion of having no expectations of how the plane would perform and instead just react to whatever was presented to me.

As I said, I know this will sit badly with quite a few people and that it goes against the conventional thinking around how to standardize your process for flying an approach. I used to fly with 'the numbers' ready to go but once I started flying in the weather (outside of the sim), I realized that I was almost never exactly at those numbers, in which case the numbers were effectively useless. That, and I was spending way too long on the approach to begin with....why do I need to be at 80kts when I'm still 10+ miles from the field? Hit the gas, get on with it, get down sooner and spend less time performing such an intense task.

Keith,

I know you are familiar with the arguments and have a well thought out plan that works well for you. A lot of pilots struggle and get behind the airplane because they spend too much time manipulating the controls to get speed/profile they want. Learning some baseline pitch/power configurations and standardization procedures for each phase of flight tends to solve the problem pretty quickly.

I'd argue that having a set of predictable performance numbers makes you MORE in tune to the dynamic changes in the environment. For example, if you end up needing a higher descent rate than expected, you'll realize that it's because of a decreasing headwind and make a discrete power change to compensate. Then you learn to anticipate and alter your numbers accordingly. It can also be another layer of protection against forgetting items. If your speed is 10-20 knots faster than the numbers predict, you'll probably notice that the gear never came down. The numbers are not fixed, but serve as a baseline from which you can make predictable changes to meet the demands of a dynamic environment.

“IFR: A Structured Approach” by John Eckalbar is a great book on this subject.

Ryan,

The idea of having a baseline then noting the deviation from the baseline is reasonable. I do use that technique when I'm VFR when making a normal landing. If I'm on a normal glide path at typical weight with more than 13.5" of MP, then I probably have a headwind, it's it's less than 13.5" MP then I probably have a tailwind. I haven't found it to be as useful with IFR approaches thus far, though.

I tend to agree with Keith. If its uncomfortably bumpy i slow down. If i want my gear down before i land i slow to gear down speed before landing. Ok maybe the FAF.

I have seen some value in initial training with power settings ie: pull out power to come down and they remove a half inch of manifold pressure. So give them a number for that like "pull out power to about 13 inches of manifold pressure untill they get the hang of it.