intro

The single-engine approach in the Seminole is one of the most challenging, and thus feared, tasks on the multiengine checkride. You need to fly the airplane, handle a simulated engine failure, hold heading, course, and altitude, all while setting up and flying an instrument approach in an expensive airplane that you likely have less time in than other types you’ve done previous checkrides in. These factors combine to make this a challenging maneuver. There are a number of things you can do ahead of time to make this maneuver more manageable. Let’s dive in.

planning

The OEI approach builds on several skills that you’ve used in the past, so make sure they’re all sharp before adding any complexity.

1. Scope out approaches you’re likely to fly and any challenges they may entail.
2. Ensure you have a rock-solid grasp of constant-speed props.
3. Know your power settings and energy management techniques before you get in the airplane.
4. Practice your OEI flow until you can do it in your sleep. Before you start any evaluation event, make sure you’re aligned with your evaluator on their expectations (read/do, flow/confirm, CDV, etc.). Practice different techniques so you don’t have to swing at a curveball.
5. Verbalize every step in the process. If your instructor or evaluator knows what you’re thinking, they’ll have fewer questions.

I like to plan no troubleshooting inside 5 miles from the FAF because there’s simply too much going on (red arc on the right). Likewise, if I’m within 200 feet of my FAF altitude, I plan to feather the dead engine immediately. The ACS gives us 100 feet of wiggle room on altitude. The Seminole has two engines: the “altitude breakeven engine” and the “climb engine.” If you’re troubleshooting a windmilling engine, you’re descending. If you don’t have the altitude to trade for speed, that means you will descend below the FAF altitude at ~200 FPM (depending on conditions), meaning you have 30 seconds before you bust your 100-foot box. Even ignoring the ACS and the canned scenario of a checkride, you’re probably better off focusing on flying the airplane in most real-world circumstances if you’re close to your destination.

From an airspeed standpoint, 110 KIAS is a good setup speed, usually about 20/21. It gives you enough margin over blue line (88 KIAS) to feather an engine, but it’s also slow enough to give you more time to think and react. Going any faster will entail more windmill drag and thrust on the good engine, which will cause a more brisk yaw and force you to react more quickly, which makes it harder.

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Losing an engine before the FAF

Let’s say you’re 4 miles (~2 minutes) from the FAF and your left engine loses thrust (either a real failure or your evaluator/instructor pulling a torque lever to idle). Because you’re at a moderate speed with a low prop setting, several things are working in your favor:

1. The “dead” engine’s governor is working to maintain 2100 RPM, not a higher amount, so the windmill drag is less severe.
2. The “good” engine is 20/21, so it’s at partial power and not creating as much asymmetrical thrust.
3. Your airspeed is slow enough that the drag scaling is not as extreme.

Together, these three factors will slow down the pace at which the airplane starts to pull left, buying you valuable time to react (see sketch above). You’ll typically spot it first when you see the HSI needle drifting to the right as you yaw left, so start out with:

1. 88 (blue line or faster, keep it straight (primary right rudder input for directional control).
2. Reds (full mix): usually not much happens here.
3. Blues (full prop): by advancing the props, your “dead” engine is making more windmill drag and your good engine is making more power (torque*RPM). You need to anticipate this yaw and be prepared to add a secondary right rudder input (see sketch below). I like to keep looking at the HSI needle as I do this to match the prop advance with the rudder input.
4. Blacks (full throttles): as you advance your torque levers, you get more power on the good side. As with step #2, look at your HSI as you advance them to match your tertiary right rudder input.
5. Feathering: as you pull the left prop handle (or tap in a simulation while your instructor brings it up to 11 MP), the windmill drag will go away, so you now need a quaternary rudder input which is a reduction of right rudder. Again, look at the HSI as you do this.

Power adjustment: if it’s a cold day near sea level, you might have a bit of extra power on your good engine, so adjust as needed to maintain 100 KIAS.

Students who get in trouble with the OEI approach typically get the primary rudder input, but don’t fully understand the nuances of the next three, and thus drift off track.

Starting down

As you get to about a mile to half a mile from the FAF, lower the gear and hold 100 KIAS (this keeps your 10-knot ACS buffer above blue line). Flaps are often a hotly-debated topic. I like to keep them up in the Seminole for the following reasons:

1. Flaps 25 and 40 add a bunch of drag, which is why the POH says not to do it.
2. Clean vs flaps down stall speeds are so close (57 and 55) that flaps don’t help much with lift. Adding flaps 10 is one more task that disrupts trim and takes away brain space.
3. Flaps give you a lower trailing-edge camber line and consequently more nose-low deck angle on approach, requiring more flare. If you misjudge your airspeed on short final, you have the option with no flaps to land a bit flat and fast. Keep your options open.
4. Go arounds: if you absolutely need to do it, one less thing to worry about.

As you start down, you need about 21 MP at full prop on your good engine to maintain 600 FPM. Ease your rudder and throttle simultaneously and check your HSI to make quicker adjustments. This is where knowing your planned sink rate is important. If you need to make profile corrections, make 1 MP adjustments in conjunction with small pitch adjustments (half tick mark G1000, half ball-width steam gauge) to maintain speed while shallowing or steepening your descent by 100ish FPM, then re-evaluate. If the needle is trending back to the middle, don’t keep chasing it.

Losing an engine inside the FAF

If you keep your normal 20/21 setup level prior to the FAF, you’ll need about 17/21 on both engines with gear down to keep a 600 FPM descent going inside the FAF. Plan in an AEO scenario to advance the props on short final like you would in the pattern. Lower prop settings are your friend downhill as well. The same windmilling aerodynamics apply as you lose your bad engine. Now you need to maintain glide path instead of hold altitude. My technique for that is as follows:

1. Reds/Blues/Blacks and associated rudder inputs and check if we're still on profile.
2. If still on profile, pull torque lever back to about 22 MP while easing the rudder and look for desired sink rate. If low, re-intercept. If high, pull to 20 MP and re-intercept.
3. Feather the “dead” engine and ease rudder input.
4. Immediately pull the good torque lever back to 21 MP while easing more rudder and checking sink rate. Verify glide path and lateral course and make measured tweaks.

The big thing to focus on with this scenario is profile control. You will have sufficient excess thrust that you can get high on profile if you focus too hard on feathering at the expense of flight path managment, so keep focusing on your needles as you make each input, and plan ahead of time so that you’re 90% of where you need to be instead of guessing on your power settings.

Landing

As you come out at mins, you should be looking at the thousand-footers. Gradually start easing back your good torque lever to bleed speed and start your flare. The ACS says you’re good anywhere on the first third, so if you picked a long runway you can afford to ease more gradually in order to maintain more precise centerline control. If you kept your flaps up, you can also afford to be a bit fast relative to your target speed and still make it if you land a bit flat. As you close the good throttle, that engine is now making windmill drag, so you’ll need to lift off that rudder and apply a bit of opposite rudder, which may feel weird (see sketch). This is why setting yourself up for success and doing it all gradually is your best friend. [Note for MEIs: monitor the MP of the "failed" engine and keep it about 11 MP to simulate the feathered state. Hold it there in the flare and only retard it gradually once on the ground to give your student the correct feel for the need for opposite rudder mentioned above.]

Chair flying and sim work

I strongly recommend using a swivel chair when learning your OEI flows and the effect that each input has on your aircraft. Grab an instructor or study buddy who can twist the chair while you make each input and verbalize what you’re looking at. If you have access to an ATD configured to represent a Seminole, fly the OEI approach several times to hone your scan. I personally prefer the steam-gauge panel because the VSI and HSI/GS are right next to one another, so it’s easier to control profile, but YMMV.

My best multi students who got done with the shortest amount of time in the airplane were the two who spent the most time flying the swivel chair and sim. You can save a lot of money by getting the basics down early to focus on refinement in the real aircraft.

A word of caution on simulated vs actual failures: I recommend practicing simulated and actual flows (tapping vs pulling levers) and adjusting callouts accordingly depending on whether you're in the sim or the airplane. I also recommend having your instructor do all the simulated flows with you in the sim so that you're proficient with both. This will help identify an actual failure in a training environment as well as reduce the likelihood of killing a live engine near the ground during a simulated failure. Brief this with all your instructors and evaluators so everyone’s crystal clear on what’s happening.

tips for instructors

We all know this one's hard. Here are some tricks I've developed that may help you get your students ready faster:

1. Have your multi students backseat one another. They'll learn faster critiquing one another's work and observing things as they chair fly the drill themselves from the back seat. One downside is that one student will likely get better at task A while the other gets better at task B, and they will compare themselves. It's important to flag this ahead of time and reinforce that it's a normal part of the process and they'll usually learn faster despite some of the frustration. If a student really hates the eyeball pressure, reassess.
2. Feather drills on an airway: pick a line of fixes, create one in the box with a VNAV profile, or make up a new distance ("Your simulated FAF is 5 miles before ABCDE fix"). Pull the torque lever and have the student go through the whole flow, gear down, and stable descent setup, then have them clean it up and do it again. This way they get several repetitions in quick succession.
   
3. Help your student create a scan pattern that helps them catch the wandering needle quickly. Most busts start with the secondary rudder input, so pause and chair fly that sequence on the ground where time is not a threat until they've fully understood it. Most students who run slowly didn't learn to crawl and walk properly.
   

Please send me any other tricks you've developed.