Taxiing and Sailing (ASES, AMES)

The objective is that you understand taxiing and sailing, can apply that knowledge, manage associated risks, demonstrate appropriate skills, and provide effective instruction (ACS AI.V.E). The skill elements are unusually specific about the technique set: position the flight controls, flaps, doors, water rudders, and power correctly for existing conditions to follow the desired course while sailing and to prevent or correct for porpoising and skipping during step taxi (AI.V.E.S6), and exhibit steering and maneuvering while maintaining situational awareness and desired orientation, path, and position using idle, plow, or step taxi technique, as appropriate (AI.V.E.S7). You are graded on choosing the right technique for conditions and on being able to explain to a learner why that technique, which is the instructor half.

Idle taxi, plow taxi, and step taxi (AI.V.E.S7). The ACS phrasing — "as appropriate" — is the whole test: the technique is selected for wind, water state, traffic, and the maneuvering task at hand, not by preference. Build your lesson around the decision, because that is what transfers. A learner who can perform all three but cannot say which one this situation calls for has learned three motor skills and no judgment.

Five, and three of them have no landplane equivalent (AI.V.E.R1 through R5):

• Activities and distractions
• Porpoising and skipping — a technique-driven hazard during step taxi, called out as a risk in its own right
• Low visibility taxi and sailing operations
• Other aircraft, vessels, and hazards — the surface is shared with traffic that is not on your frequency and not bound by the AIM
• Confirmation or expectation bias as related to taxi instructions

The seaplane-only additions are porpoising/skipping and vessels. Note also that you cannot simply stop: a seaplane on the water is always moving relative to wind and current, which is why planning and following the most favorable taxi or sailing course for current conditions is its own skill element (AI.V.E.S8).

The ACS lists USCG Navigation Rules among this Task's references, and the skill element requires you to abide by right-of-way rules, maintain positive airplane control, proper speed, and separation between other aircraft, vessels, and persons (AI.V.E.S9). The instructor point: a student trained only on 91.113 will meet boats that operate under a different rule set and no radio. Teach the learner to treat every vessel as unpredictable and to build separation early, because a seaplane's ability to stop and hold position is limited by wind and current in a way a landplane's is not.

Yes, one narrow exception. 91.107(a)(3) requires each person on board to occupy an approved seat or berth with safety belt, and shoulder harness if installed, properly secured during movement on the surface, takeoff, and landing — but for seaplane and float-equipped rotorcraft operations during movement on the surface, the person pushing off the seaplane from the dock and the person mooring it at the dock are excepted from those seating and belt requirements. Everything else in 91.107 still applies: the PIC ensures each person is briefed on how to fasten and unfasten the belt and harness before takeoff (91.107(a)(1)), and notified to fasten them before the aircraft is moved on the surface (91.107(a)(2)).

Brief it as a two-person procedure with agreed commands, the same way any procedure with a person outside the airplane is briefed:

• Who does what, and in what order — and that nothing happens until you acknowledge.
• Propeller avoidance, in explicit terms. The AFH's warning applies with more force on a dock than on a ramp: the propeller is nearly invisible, and serious injuries and fatalities have occurred when people who had just started an engine walked or reached into the propeller arc (AFH ch. 2).
• What you will do if the airplane starts moving before they are aboard, so the student's plan is not improvised while holding a wing strut.

Meanwhile you are at the controls, watching wind and current rather than the student, because the departure from the dock in a safe manner, considering wind, current, traffic, and hazards is the skill element (AI.V.E.S4) and the drift starts the instant the line is off.

Use the telling-and-doing technique, which suits this well because sailing rewards verbalization (AIH ch. 9):

1. Instructor tells, instructor does — you sail, narrating the wind and current picture, why the flaps, doors, and water rudders are where they are, and what the airplane will do next.
2. Student tells, instructor does — the student calls the configuration and the course while you operate. This is where a misconception about which surface is doing the work surfaces cheaply, and primacy says fixing it here is worth more than fixing it later.
3. Student tells, student does — the student sails and verbalizes; you guard the controls.

The explanation phase happens before you leave the dock, with objectives, completion standards, safety procedures, and an explicit invitation for questions (AIH ch. 9). On the water there is no place to stop and re-brief.

Then Task D comes with you. AI.V.E.S10 requires you to comply with the applicable taxi elements in Task D if the practical test is conducted in an amphibious airplane — so the runway holding position markings and signs, the taxiway and runway guard lighting, the brake check, the crosswind control positions, and the runway incursion avoidance material in Task V.D are all fair game in the same test. Study V.D as part of this Task, not as an alternative to it.

The same currency discipline as the landplane Task: current airport aeronautical references and information resources such as the Chart Supplement, airport diagram, and NOTAMs (AI.V.E.K2). Radio procedure is called out separately for towered and nontowered seaplane bases (K7b), and the skill elements require clearances and instructions to be received and correctly read back where applicable (AI.V.E.S1) and an appropriate airport diagram or taxi chart used, if published (AI.V.E.S2) — note "if published," which is a real limitation at many seaplane bases and the reason the pre-departure survey has to be taught as a habit rather than a chart lookup.

Add the two chart families a landplane student never opens: nautical charts from NOAA's Office of Coast Survey, and the Coast Guard light lists describing lightships, lighthouses, buoys, and daybeacons on all navigable U.S. waters (FAA-H-8083-23 ch. 1).

Two systems at once — the aeronautical one and the maritime one — and the maritime one is the half that gets skipped.

• Seaplane landing areas carry the familiar rotating beacon, but the colors alternate white and yellow; a double white flash alternating with yellow identifies a military seaplane base. On charts, seaplane landing areas use land-airport symbols with an anchor in the center, tick marks for fuel and services, a double ring for military (FAA-H-8083-23 ch. 1).
• Buoys and daybeacons — buoys float on a cable or chain; daybeacons are a marker on a piling driven into the bottom. Approaching from seaward, the left (port) side of the channel is marked with black or green can buoys carrying odd numbers that increase toward the coast; the right side with red nun buoys carrying even numbers. The mnemonic is "red, right, returning." Black-and-white vertically striped buoys mark the center of the channel or fairway, lettered from A seaward.
• At night, black or green buoys show green or white lights; red buoys show red or white lights; some unlighted buoys carry reflectors of the same significance.

Two cautions to teach explicitly: the chain length means the buoy may sit some distance from its charted position, so never pass close aboard one, and other buoyage systems exist — sometimes exactly the reverse of the above — so a pilot operating in new waters is obligated to learn the local system.

Most established seaplane bases have a windsock, and that is where you start. When there isn't one visible, teach the surface itself as the instrument (FAA-H-8083-23 ch. 6):

• Boats lying at anchor weathervane and point into the wind — with the caveat that a boat on a stern anchor will not swing with the wind.
• A glassy band of calm water on the upwind shore of a lake.
• Gulls and waterfowl land into the wind and sit heading into it on the surface.
• Smoke, flags, and the set of sails.
• Wind streaks parallel to the wind: in light winds, long narrow streaks of smooth water through the wavelets; in about 10 knots or more, foam accents them into distinct white lines. Streaks show the axis very accurately but not the direction — an east-west streak could be either — so the pilot still has to resolve which end is upwind.
• Whitecap foam appears to move into the wind. That's an illusion from the waves moving faster than the foam, and it is the cue students get backwards.

The instructor point that generalizes: shorelines and hills bend the wind, so a wind from one direction on this side of the lake is no promise about the far side. Teach the student to re-read the surface at the far end of the taxi, not once at the dock.

The lights and the rules are the airplane's, but the audience is not. Anti-collision lights on at all times before engine start, position (navigation) lights on for night operations, taxi or landing light on once ready to move (AFH ch. 2, ch. 11) — the same standard as Task V.D, and Task V.D's material comes with you under AI.V.E.S10 if the test is in an amphibian.

What changes is who is reading them. Position lights are arranged like a boat's — red left, green right, white on the tail (AFH ch. 11) — which means the boat traffic sharing your surface is reading them under the maritime convention they already know. That is a genuine teaching hook: your lights are legible to vessels, so your lighting is part of the separation you're required to maintain from other aircraft, vessels, and persons (AI.V.E.S9). Then the AFH's own limits still apply — landing lights drain the electrical system and can overheat, so use them only as needed, and don't blind the boat you're passing.

Almost everything a landplane student does at a run-up pad, because there is no run-up pad. The seaplane handbook is blunt about the sequencing: perform all of the pre-takeoff checks while taxiing to the takeoff position, and all checks are performed as the seaplane taxies, including the engine runup (FAA-H-8083-23 ch. 4). What that forces you to teach:

• Front-load the checklist at the dock. Because the pilot is often the one who shoves off, do as many items on the starting checklist as possible before shoving off — including the passenger brief and seatbelts.
• Hold the elevator control all the way back throughout the runup to minimize spray around the propeller.
• Let the seaplane turn into the wind for the runup if there is significant wind: rpm brings the nose up into the plowing position and the seaplane accelerates, and that is a relatively unstable attitude for a crosswind or gust to work on.
• Be thorough and precise, but waste no time — you are covering water while you do it, and taxi speed drops the moment power comes back.
• Look outside and talk on the radio — check for other air traffic and make the appropriate calls before takeoff.

The instructor framing for AI.V.E.S5: a checklist run while the airplane is moving is a divided-attention task the student has never done before. Teach it as call-and-response with you as the reader on the first several lessons, and hand the checklist over only when the student's head is coming up between items on its own.

In the idling or displacement position the buoyancy of the floats supports the entire weight of the seaplane, and the attitude is close to what it is at rest (FAA-H-8083-23 ch. 4).

• Power — rpm as low as possible: to control speed, to keep the engine from overheating, and to minimize spray.
• Elevator all the way back in almost all circumstances. Two reasons, and the student needs both: it keeps the nose high to minimize spray damage to the propeller, and it keeps more of the water rudder underwater, which improves maneuverability.
• The exception — a strong tailwind component or heavy swells could let the wind lift the tail and flip the seaplane. Then hold elevator forward enough to keep the tail down. Teach the exception the same day as the rule, or primacy will make the rule unconditional in the student's head.
• Speed — this is the position for most taxi operations; keep it below 6–7 knots to minimize spray reaching the propeller, and slower still in congested or confined areas, because inertia at higher speed lets the seaplane coast farther and even a minor collision does serious damage.
• Wakes and swells — cross at about 45° to minimize pitching and rolling and the possibility of an upset.

Because it is expensive and hot for what it buys. Applying power shifts the center of buoyancy back as hydrodynamic pressure builds on the float bottoms, putting more weight behind the step; the floats are narrower toward the rear, so the sterns sink farther in, and holding the elevator full up pushes the tail down further with propeller airflow. Result (FAA-H-8083-23 ch. 4):

• High drag — a relatively large amount of power for a modest gain in speed.
• Spray on the propeller anyway, because of the higher rpm, even with the nose high.
• Heat — high power and low cooling airflow build engine temperature. Monitor engine temperature carefully.

So the handbook's position is that plowing is not recommended as a taxi technique; it is the transitional phase between idle taxi and planing. Teach it as a phase the student must recognize and pass through deliberately, not park in. The one deliberate use is the plow turn, and even there the handbook is narrow: plow turns are useful only in very limited situations because of the dangers they expose the pilot to. Not in rough water or gusty conditions — floatplanes are least stable in the plowing attitude and very susceptible to capsizing, and despite the nose-high attitude the high power setting often results in spray damage to the propeller. In most windy situations it is much safer to sail the seaplane backward than to attempt a plow turn, which is the judgment call you are really teaching.

On the step, most of the weight is supported by hydrodynamic lift rather than buoyancy — the float works like a water ski, and raising the rear of the floats clear of the water sharply reduces drag (FAA-H-8083-23 ch. 4).

• There is one pitch attitude that produces minimum drag. An experienced pilot finds the "sweet spot" by feel; a beginner has to gauge the nose against the horizon. Say that out loud to the student — it manages the expectation that feel should arrive on lesson one.
• Nose too high — the rear of the floats contacts the water, drag rises, and the seaplane settles back toward plowing. Only slightly high and it stays on the step but accelerates very slowly.
• Nose too low — more of the front of the float contacts, which is called dragging, and it can feel to the student like applying brakes in a landplane.
• To taxi on the step rather than take off, reduce power as the seaplane is eased onto the step. More power is needed with a heavy load, but 65 to 70 percent of maximum power is a good starting point.
• Water rudders must be retracted at these speeds to prevent damage; there is plenty of airflow for the air rudder. Turns on the step are gentle, air rudder and ailerons, with elevator holding a precise planing attitude — ailerons into the turn, except when aileron into the wind is needed to keep the upwind wing from lifting.

The go/no-go the student must own: step taxi only where they are confident of sufficient water depth, no floating debris, no hidden obstructions, and no other water traffic nearby. Never step taxi in shallow water — if the floats touch bottom at speed, the sudden drag is likely to flip the seaplane. And if a wake is unavoidable, reduce to idle and idle taxi across it, preferably at an angle.

Different mechanisms, different feel, different fix — and the handbook says new seaplane pilots confuse a skip with a porpoise, so name the distinguishing cue first.

Porpoising is a rhythmic pitching motion caused by dynamic instability along the float bottoms while on the step. An incorrect planing attitude sets off a cyclic oscillation that steadily increases in amplitude unless the proper pitch attitude is reestablished; uncorrected it will nose the seaplane into the water, with extensive damage or capsizing. Feel: a rocking-chair fore-and-aft motion. Recovery for the nose-low case: timely back pressure on the elevator, applied and maintained until it stops — and if it hasn't stopped by the time the second oscillation occurs, reduce the power to idle and hold the elevator control back firmly so the seaplane settles onto the water with no further oscillation.

Skipping occurs when landing at excessive speed with the nose at too high a pitch angle, putting the seaplane at the upper trim limit of stability; it can also come from crossing a boat wake while on the step or during takeoff. Feel: vertical G, like bouncing a landplane. Recovery: increase back pressure and add enough power to keep the floats off the water, then establish the proper pitch attitude and reduce power gradually to settle on. Skipping oscillations do not grow in amplitude the way porpoising does, but they pound the floats and airframe and can lead to porpoising.

The instructor's own limit belongs in this card: divergent porpoising is the case where you take the airplane, and you say so in the brief before the first step taxi, not during the second oscillation.

Sailing is guiding the seaplane on the water using the wind as the main motive force — the technique for situations where conventional taxiing is undesirable or impossible, and the thing that lets a skilled pilot fit into a space that looks impossible (FAA-H-8083-23 ch. 4). Because the seaplane weathervanes into the wind, sailing usually means moving backward.

The mechanism, which is what you narrate:

• Keel effect. With the engine idling or off, swing the tail a few degrees with the air rudder and the seaplane sails backward in the direction the tail is pointed — the sterns of the floats have become the front as far as the water is concerned. Lift the water rudders, because their action is counter to what you want.
• The hazard of doing it too fast. The rear portions of the floats are smaller and less buoyant; in a strong wind with speed building, the sterns can submerge and dig in, and combined with the wind's lift over the wings the seaplane could conceivably flip over backward. Answer: full forward elevator to keep the sterns up and the nose down, and adding power also helps.
• Cancel the motion and the mechanism inverts. With enough thrust to exactly cancel the wind's backward motion, there is no movement relative to the water, so keel effect disappears; now turning the fuselage a few degrees gives the wind a surface to push against and the seaplane moves sideways in the direction the nose is pointed. Combining the two is how you sail around an obstacle and into a confined dock.
• Increasing the sail area. With the engine off, lowering the flaps and opening the cabin doors adds air resistance and sailing speed — but may reduce the effect of the air rudder. If engine-off sailing gives too much downwind motion and an idling engine too much thrust, carburetor heat or one magneto trims the power slightly — neither for extended periods; better to start the engine briefly to slow down.

That current can beat the wind, with a number to make it stick: with a seaplane of average size and power at idle, a 5-knot water current can offset a 25-knot wind in the opposite direction (FAA-H-8083-23 ch. 4). A 5-knot current will carry the seaplane against a 25-knot wind.

The mechanism the student has to hold onto: keel effect only works when the floats are moving through the water. If the current is what's moving the seaplane, there may be little or no motion relative to the water even though the seaplane is moving smartly relative to the shore — so the rudder does nothing and the student's mental model quietly fails. Using wind, current, and thrust to track a desired course requires careful planning and a thorough understanding of the various forces at work, which is exactly why this is a Deep Dive card and not a checklist item.

Two more for the brief: evaluate wind and current carefully before taxiing into a confined area, or the seaplane may be driven into obstructions; and in a flying boat with the engine shut down, the hull gives less keel effect in proportion to the side area, so most sail backward and toward whichever side the nose is pointed regardless of wind velocity — to sail straight back, release the controls and let the wind steer.

The handbook's guidance doubles as your lesson-planning rule: each type of seaplane has its own peculiarities, so practice sailing until thoroughly familiar with that particular type — in large bodies of water such as lakes or bays, but sufficiently close to a prominent object to evaluate performance (FAA-H-8083-23 ch. 4). A student sailing in open water with nothing to reference is getting no feedback and learning nothing.

The instructor reading of that passage: the type-specific caveat applies to you first. If you're teaching in a model you haven't sailed, your ability to perceive a problem, decide upon a course of action, and physically react is untested in the one regime where there are no brakes and no place to stop (AIH ch. 9) — and the AIH's rule is that learners should never be allowed to exceed the flight instructor's limits. Get current in type before you take a student to a dock in a strong wind.