Study guide
20.1 Seaplane and Water Operations Knowledge
FAA Private Pilot — Airplane PAR
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1 Introduction & Exam Overview
1.1 Current Exam Facts 1.2 ACS Codes, the AKTR, and How to Use This Guide
2 Pilot Qualifications & Medicals
2.1 Eligibility, Training, and Knowledge-Test Authorization 2.2 Private Pilot Privileges and Limitations 2.3 Medical Certificates, Duration, and Disqualification 2.4 BasicMed (14 CFR 61.113(i) and Part 68)
3 Airworthiness, Documents & Currency
3.1 Required Pilot and Aircraft Documents 3.2 Inspections, Airworthiness Directives, and Preventive Maintenance 3.3 Inoperative Equipment and 91.213 3.4 Recent Flight Experience and the Flight Review
4 14 CFR Part 91 Operating Rules
4.1 Right-of-Way, Minimum Safe Altitudes, and Speed Limits 4.2 VFR Cruising Altitudes, Altimeter Settings, and Oxygen 4.3 Fuel Requirements, Transponder, ADS-B, and ELT 4.4 NOTAMs, TFRs, and Accident/Incident Duties
5 National Airspace System
5.1 Class A, B, and C Airspace 5.2 Class D, E, and G Airspace and VFR Weather Minimums 5.3 Special Use Airspace 5.4 Other Airspace, TFRs, TRSA, ADIZ, and SFRA
6 Aviation Weather Theory
6.1 Atmosphere, Pressure, Temperature, and Density 6.2 Stability, Clouds, and Moisture 6.3 Air Masses and Fronts 6.4 Wind, Jet Stream, and Local Wind Systems
7 Weather Hazards
7.1 Thunderstorms and Convective Weather 7.2 Structural Icing, Frost, and Carburetor Ice 7.3 Fog, Low Ceilings, and Visibility 7.4 Wind Shear, Microbursts, Turbulence, and Mountain Waves
8 Weather Products & Briefings
8.1 METAR Decoding 8.2 TAF and Graphical Forecast Products 8.3 PIREPs, AIRMET, SIGMET, Convective SIGMET, and Winds Aloft 8.4 Briefings and Go/No-Go Decisions
9 Principles of Flight
9.1 Four Forces and Lift Production 9.2 Angle of Attack, Critical AoA, and Stalls 9.3 Drag, L/D, and Ground Effect 9.4 Axes, Stability, and Flight Controls
10 Maneuvering Flight, Stalls & Spins
10.1 Load Factor, Bank Angle, and Stall Speed 10.2 Left-Turning Tendencies 10.3 Slow Flight, Power-On/Off Stalls, and Spin Awareness 10.4 Steep Turns and Ground-Reference Maneuvers
11 Powerplant, Fuel & Electrical Systems
11.1 Reciprocating Engines, Mixture, Detonation, and Preignition 11.2 Ignition, Magnetos, Carburetor vs Fuel Injection 11.3 Fuel Grades, Contamination, and Fuel-System Management 11.4 Electrical System and Alternator Failure
12 Flight Instruments & Avionics
12.1 Pitot-Static Instruments and Blockage Errors 12.2 Gyroscopic Instruments, Vacuum Failure, and Magnetic Compass Errors 12.3 Engine Instruments, Transponder Modes, and Basic Avionics
13 Aircraft Performance
13.1 Pressure Altitude, Density Altitude, and Performance Effects 13.2 Takeoff and Climb Performance 13.3 Cruise, Descent, and Landing Performance 13.4 Wind, Gradient, Surface, and Crosswind Component
14 Weight and Balance
14.1 Weight-and-Balance Principles 14.2 Moment, CG, and Sample Computations 14.3 Forward and Aft CG Effects 14.4 V-Speeds, Markings, and Limitation Placards
15 Charts, Pilotage & Dead Reckoning
15.1 Sectional Chart Symbology and Airspace Depiction 15.2 Pilotage and Dead Reckoning 15.3 Variation, Deviation, Wind Triangle, and E6B 15.4 VFR Cross-Country and Fuel Planning
16 Radio Navigation, Lost Procedures & Airport Operations
16.1 VOR Navigation 16.2 GPS, RAIM, and Radar Services 16.3 Lost Procedures and Diversion 16.4 Communications, Light-Gun Signals, Lighting, and Traffic Patterns
17 Aeromedical Factors
17.1 Hypoxia, Hyperventilation, and Carbon Monoxide 17.2 Spatial Disorientation, Illusions, and Vision 17.3 Scuba-to-Flight, Alcohol/Drugs, and IMSAFE
18 ADM, Night Operations & Emergencies
18.1 ADM, Hazardous Attitudes, PAVE, and DECIDE 18.2 Night Operations and Night Illusions 18.3 Emergency Descent, Engine Failure, and System Malfunctions 18.4 Survival Gear, ELT, and Forced-Landing Considerations
19 Preflight Procedures & Airport Ground Operations
19.1 Preflight Assessment, Airworthiness Determination, and the Preflight Inspection 19.2 Flight Deck Management, Passenger Briefings, and Engine Starting 19.3 Taxi Operations: Signs, Markings, Lighting, and Runway Incursion Avoidance 19.4 Before-Takeoff Check, After-Landing, and Securing the Airplane
20 Class-Specific Knowledge: Seaplane & Multiengine
20.1 Seaplane and Water Operations Knowledge 20.2 Multiengine Knowledge: VMC, VYSE, and Engine-Out Fundamentals
20.1 Seaplane and Water Operations Knowledge
Key Takeaways Explain This Topic AI
Glassy water removes depth perception, so the technique is a known pitch attitude and a rate of descent of about 150 feet per minute carried to touchdown using shoreline references.
Porpoising is a longitudinal oscillation caused by planing at too low a pitch attitude; correct it with back pressure, and close the throttle if it does not stop within two or three cycles.
Water rudders are retracted for takeoff, landing, and step taxi, and extended for displacement taxi, docking, and sailing.
14 CFR 91.115 governs water right-of-way: the aircraft or vessel to the other’s right has the right-of-way when crossing, both alter course to the right when head-on, and the craft being overtaken has the right-of-way.
A Naval Vessel Protection Zone extends 500 yards around a U.S. naval vessel; operate at minimum speed within 500 yards and stay outside 100 yards unless authorized.
Last updated: August 2026
FAA-S-ACS-6C is the ACS for the airplane category — single-engine land and sea , multiengine land and sea — so it carries a full set of seaplane knowledge elements. This section covers Task I.I (water and seaplane base characteristics), Task II.E (seaplane taxiing and sailing), the water takeoff and landing tasks in Area IV, and Task XII.B (seaplane postflight).
Reading the water surface
PA.I.I.K1 lists what to evaluate before committing to a landing area: size and location ; protected versus unprotected areas; surface wind ; direction and strength of the water current ; floating and partially submerged debris ; sandbars, islands, and shoals ; vessel traffic and wakes ; direction and height of waves ; and any other characteristic specific to the area.
Two of those deserve emphasis. Current matters because a landing that looks fine against the wind may be badly downstream over the ground, and because docking is done against the stronger of wind or current. Debris is the seaplane equivalent of an obstacle on the runway, and a deadhead log floating just below the surface is invisible from pattern altitude.
The three surface conditions and the three techniques
Condition The hazard The technique
Glassy water The surface is a mirror. You have no depth perception and cannot judge height above the water — the classic accident is flying straight into it. Set a known pitch attitude and power producing roughly 150 feet per minute of descent at a safe airspeed, using the shoreline, trees, or a dock for height reference, and hold that attitude until the floats touch. Do not chase a flare you cannot judge.
Rough water / swells Impact loads and skipping; the face of a swell can stop the floats abruptly. Land parallel to the swells where possible, touching on the crest or the back side of a swell rather than its face, with a slightly higher airspeed and the nose held up .
Confined area Obstacles on both ends and limited room to accelerate or decelerate. Full obstacle analysis, maximum-performance technique, and a firm go/no-go decision before descending below the obstacles.
Porpoising and skipping — the two named seaplane malfunctions
PA.I.I.K3 asks for the causes of porpoising and skipping and the pilot action to prevent or correct them, and these are exactly the kind of named-phenomenon items the test likes.
Porpoising is a rhythmic longitudinal oscillation on the step, caused by planing at too low (too nose-down) a pitch attitude so the bows dig in and the airplane rocks fore and aft with increasing amplitude. Correction: apply back pressure to raise the nose to the correct planing attitude. If the oscillation does not stop within two or three cycles, close the throttle and let the floats settle off the step.
Skipping is a bouncing off the tops of waves, caused by touching down in rough water at too high a pitch attitude or too fast — the airplane rebounds rather than settling. Correction: add power and go around, or lower the nose to the correct planing attitude if remaining on the water.
The symmetry is worth memorizing: porpoising is nose too low, skipping is nose too high.
Taxiing, sailing, and the water rudders
Task II.E covers taxiing and sailing. There are four distinct surface modes:
Displacement taxi — idle power, floats deep in the water, nose slightly high, a large bow wave. The slow, controllable mode. Water rudders down.
Plowing taxi — a transitional, very nose-high, high-drag attitude between displacement and step. Useful briefly for visibility over the nose; not for sustained taxiing, because it produces spray and heavy loads.
Step taxi — up on the step and planing, fast and efficient. Water rudders UP , because they will be damaged and are ineffective at speed.
Sailing — engine at idle or shut down, using the wind on the airframe with flaps, doors, and water rudders as sails to back the airplane into a dock or beach. A seaplane always weathervanes into the wind, and sailing works with that tendency rather than against it.
Water rudder discipline (PA.I.G.K1k) is a favorite test item: retracted for takeoff, landing, and step taxi; extended for displacement taxi, docking, and sailing.
Floats, charts, restrictions, and marine rules
Float and hull construction (PA.I.I.K2) changes performance: floats add weight and a great deal of parasite drag, so the takeoff run is longer, cruise speed is lower, and useful load is reduced. Floats are divided into watertight compartments — and every one of them must be pumped out before flight, because trapped water is both weight and an unknown CG shift.
Charts and directories (PA.I.I.K4): seaplane bases carry their own symbol on sectional charts, and the Chart Supplement lists seaplane bases along with their restrictions. Operating restrictions (K5) are frequently not FAA rules at all — state and local governments, wildlife refuges, and national parks regulate the water surface, and a lake that is aeronautically perfect may be legally closed.
Right-of-way on the water — 14 CFR 91.115:
General. Each person operating an aircraft on the water shall, so far as possible, keep clear of all vessels and avoid impeding their navigation .
Crossing. The aircraft or vessel to the other's right has the right-of-way.
Head-on. Each shall alter course to the right to keep well clear.
Overtaking. The craft being overtaken has the right-of-way; the one overtaking alters course to keep well clear.
Marine navigation aids (K7) include buoys, beacons, lights, sound signals, and range markers; in U.S. waters the convention is "red, right, returning" when returning from seaward. Naval Vessel Protection Zones (K8) extend 500 yards around a U.S. naval vessel: operate at the minimum speed necessary for safe navigation within 500 yards, and do not come within 100 yards without authorization. No-wake zones (K9) mean displacement taxi only.
Postflight (Task XII.B) is mooring, docking, anchoring, and beaching or ramping. All four are approached slowly, into the wind or current where possible, with the engine shut down early enough that you arrive with no more energy than you can absorb by hand, and with the floats protected from rocks and pilings.