Plan for 45 to 90 minutes, and expect somewhere near half of it to circle one number: Vmc. The multi-engine add-on oral is the most predictable checkride conversation in general aviation, because the airplane only does one genuinely new thing — it flies with an engine dead — and almost every question an examiner asks is a way of finding out whether you understand that.
Here is what actually gets asked, in roughly the order it gets asked, based on how the exam is structured and what our students report walking out of it.
What the oral covers, and what it does not
A multi-engine add-on is an additional class rating under 14 CFR 61.63(c). There is no minimum hour requirement written into the rule and no knowledge test. You need training in the areas of operation and a logbook endorsement from an instructor, then a passing practical test. That is it.
Because there is no written exam, the oral carries more weight than it would on an initial certificate. The examiner has no test score to look at. Everything they learn about what you know, they learn by asking.
The scope is narrower than your private or commercial oral was. An add-on is tested against the areas of operation in the applicable Airman Certification Standards that are specific to the new class — so airplane systems, performance, aerodynamics of engine-out flight, and the emergency procedures. You will not spend the morning on weather theory or airspace again. You may still get asked about them if something you say invites the question.
The Vmc block
This is the exam. Everything else is context.
Define it
Vmc is the minimum control speed with the critical engine inoperative — the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is still possible to maintain control of the airplane and hold straight flight at that speed with a bank of not more than five degrees.
Two words in that definition get candidates in trouble. Control, not performance: at Vmc you can hold heading, but the airplane may be descending. And calibrated, not indicated, which is why the red line on your airspeed indicator is a published indicated figure and not the certification number itself.
The conditions it was determined under
Expect to be walked through the certification conditions one at a time. The list a well-prepared applicant recites:
- Critical engine windmilling — the propeller in the position it automatically assumes when the engine fails
- Maximum available takeoff power on the operating engine
- Most unfavorable weight
- Most rearward center of gravity
- Landing gear retracted
- Flaps in the takeoff position
- Cowl flaps in the takeoff position
- Airplane trimmed for takeoff
- Airborne and out of ground effect
- Bank of not more than five degrees toward the operating engine
The success criteria are a heading change of no more than 20 degrees and a rudder force not exceeding 150 pounds. That 150-pound figure comes up often, because it explains something useful: Vmc is a test pilot's number, established by a strong person pushing very hard. Your own leg is not the certification standard.
What changes it in flight
This is where the examiner separates memorization from understanding. Vmc is a fixed red line on the instrument, but the actual speed at which you lose directional control moves around constantly.
Aft CG raises Vmc, because the rudder arm shortens. Windmilling instead of feathered raises it. Banking toward the dead engine raises it, and does so fast — this is the single most dangerous thing a pilot can do while slow on one engine. Ground effect lowers it. Altitude lowers it for a normally aspirated airplane, because the operating engine makes less power and produces less asymmetric thrust.
Then the one that catches people: lighter weight raises Vmc. Students want weight to behave the way it does for stall speed. It does not. When you bank into the operating engine, the horizontal component of lift helps the rudder fight the yaw, and a heavier airplane generates more of that horizontal component. A light airplane with two people and low fuel is the one that will hurt you.
The follow-up question, almost every time: at altitude, which comes first — Vmc or the stall? For a normally aspirated twin, high enough up, the airplane will stall before it reaches Vmc, and a stall with asymmetric thrust and a boot full of rudder is how twins end up inverted. That is the whole reason Vmc demonstrations are terminated at the first indication of a stall.
The numbers for the airplane you are testing in
Our multi-engine training happens in a Piper PA-44-180 Seminole. The speeds you will be asked to produce from memory: Vmc 56 KIAS, Vsse 82 KIAS, Vyse — blue line — 88 KIAS, Vs0 55 KIAS, maximum gross weight 3,800 pounds. Two Lycoming engines of 180 horsepower each.
Know Vsse and why it exists. It is the minimum speed for intentionally rendering an engine inoperative, and it is a manufacturer's number rather than a certification one — a buffer built in so that training does not put you at the edge of controllability on purpose.
The critical engine question
"Which is your critical engine?"
On a conventional twin with both propellers turning clockwise, it is the left one, and the four reasons are P-factor, accelerating slipstream, spiraling slipstream, and torque. The descending blade of the right engine sits farther from the centerline, so the right engine produces a longer moment arm and a stronger yaw. Lose the left, and you are left fighting the engine with more leverage.
On the Seminole the answer is different, and this is the trap. The Seminole has counter-rotating propellers, so there is no critical engine — the failure of either produces the same yaw. Candidates who memorized "the left engine" without understanding why say the wrong thing here, and the examiner now knows exactly how the rest of the hour should go.
Performance: half the power, a fifth of the climb
Lose one engine of two and you lose 50% of your available power. You lose roughly 80% of your climb performance. Excess thrust is what makes an airplane climb, and most of the thrust an airplane produces at climb speed is already being spent holding level flight. What is left over after the loss is small.
Expect to open the performance section of the POH and work a real problem — a hot afternoon at Van Nuys with a realistic load, and single-engine rate of climb at that density altitude. Some days the honest answer is that the airplane will not climb, and saying so is the correct answer rather than a failing one. Examiners are testing whether you will accept an unwelcome number.
You should also be able to explain accelerate-stop distance and accelerate-go distance, and to say what your plan is on takeoff roll before you advance the throttles. A published number you have not turned into a decision is not useful.
Systems questions that come up almost every time
Feathering. What feathers the propeller, and why you cannot feather it after the engine has spun down on shutdown — the centrifugal latch pins engage at low RPM and hold the blades out of feather so the airplane can be started again. Applicants who have only read about this get caught. Applicants who have watched an instructor secure an engine in flight do not.
Fuel. How crossfeed works on your airplane, and what the POH prohibits. On most trainers crossfeed is for level cruise on one engine, not for takeoff and landing.
Electrical. Two alternators, one battery, and what happens to your load when one alternator quits.
Landing gear. How it is driven, and what the emergency extension procedure is when the pump quits.
The pattern across all of these is the same. The examiner is not looking for a schematic. They want to know what you would do at night over the San Fernando Valley when the thing stops working.
The regulations they actually cite
Beyond 61.63(c), the ones that come up: 14 CFR 61.57 for passenger currency, and the point that takeoffs and landings for currency must be made in an aircraft of the same category and class — your single-engine landings do not carry over. 14 CFR 91.205 for required equipment. 14 CFR 91.213 for what to do about an inoperative instrument, and whether your airplane has a minimum equipment list at all. 14 CFR 61.31 if the airplane is complex or high performance, which yours is.
If you have not read the actual text of those sections recently, read them. Examiners notice the difference between a paraphrase and a person who knows where the paragraph lives.
What it takes to get there
Most commercial pilots finish the multi-engine add-on in 10 to 15 hours of dual instruction. Our add-on is $5,100, and typical calendar time is two to four weeks for someone flying a few times a week. The rating itself is short. The oral is the part people underestimate, and the failures we hear about are almost never a botched engine-out approach — they are a Vmc conversation that went sideways in the first 20 minutes.
Two things shorten that risk more than anything else. Sit down with the POH and write out every limitation and V-speed by hand until you can do it cold. Then have someone who is not your instructor ask you the Vmc questions out loud, because knowing a thing and saying it under mild pressure are different skills.
A downside worth naming: a multi-engine rating flown twice a year is close to worthless and arguably dangerous. Asymmetric-thrust handling decays quickly. If you are adding the rating for a résumé line and nothing else, budget for recurrent flying, or the money is better spent on your instrument rating instead.
Where to start
If you are working toward the multi and want to see the airplane and the syllabus before you commit, our multi-engine training program at Van Nuys lays out the sequence, and the multi-engine rating requirements page covers the eligibility side. If you are earlier in the process, a $229 discovery flight puts you in the left seat over Los Angeles the same week, and a free in-person consultation at our office gets you a written plan with dates and costs before you spend anything. Our students rate us 5.0 stars across 85 Google reviews, and Van Nuys gives us 355 flyable days a year to work with.
Call (818) 290-8249 or come see us at 7900 Balboa Blvd, Suite 108A, Van Nuys, CA 91406.
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