19.1 Preflight Assessment, Airworthiness Determination, and the Preflight Inspection
Key Takeaways
- 91.7(a) prohibits operating a civil aircraft unless it is in an airworthy condition; 91.7(b) makes the pilot in command responsible for determining that the aircraft is in condition for safe flight.
- Airworthy has two halves: the aircraft conforms to its type certificate (including STCs and complied-with ADs), and it is in condition for safe operation. Both must be true.
- 91.103 requires the PIC to become familiar with all available information concerning the flight, and specifically requires weather reports and forecasts, fuel requirements, alternatives, known traffic delays, runway lengths at airports of intended use, and takeoff and landing distance data.
- The preflight inspection is flown from the AFM/POH checklist for that make and model, not from a generic walk-around card; ACS II.A asks which items you check, why you check them, and how you would detect a defect.
- Visually verify fuel quantity and grade at the filler and sump every tank and drain — fuel gauges are required equipment but are not a legal or practical substitute for looking.
Everything in this chapter comes from ACS Area of Operation II, Preflight Procedures, the block the knowledge test uses for "before you release the brakes" questions. Section 19.1 covers Task II.A, Preflight Assessment. The ACS splits the task into three questions, and the test asks all three: is the pilot fit, is the airplane appropriate and airworthy, and has the required preflight action been completed?
Pilot self-assessment comes first
PA.II.A.K1 is pilot self-assessment. That is the IMSAFE checklist and the personal-minimums habit from Section 17.3, plus the P in the PAVE model from Section 18.1. On the written test, self-assessment questions are usually dressed as a scenario — a pilot with a head cold, a pilot 5 hours into a 20-hour duty day, a pilot who took an over-the-counter antihistamine — and the correct answer is almost always the one that cancels or delays. 61.53 is the regulation with teeth here: you may not act as pilot in command while you know, or have reason to know, of a medical condition or medication that makes you unable to meet the standards of your medical certificate or BasicMed.
"Appropriate and airworthy" — two different determinations
PA.II.A.K2 asks you to determine that the airplane to be used is appropriate and airworthy. They are separate findings.
Appropriate means the airplane matches the mission and matches your certificate. Do you hold the category and class rating? Does it need a high-performance, complex, tailwheel, or high-altitude endorsement? Will it carry the load to the destination with legal reserves at a legal CG? Is it legal for the operation — day VFR only, or equipped for night under 91.205(c)?
Airworthy is the 91.7 term, and it has two halves that both have to be true:
- The aircraft conforms to its type certificate — including supplemental type certificates and any alterations properly recorded — and all applicable Airworthiness Directives have been complied with.
- The aircraft is in condition for safe operation.
91.7(a) says no person may operate a civil aircraft unless it is in an airworthy condition. 91.7(b) puts the determination on the pilot in command, and requires the PIC to discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur. The mechanic signs the inspection; you make the airworthiness determination on the day you fly.
The paperwork side of that determination is Chapter 3: the ARROW documents aboard (Section 3.1), the inspections current (Section 3.2), and any inoperative equipment resolved through 91.213 (Section 3.3).
91.103 — preflight action
PA.II.A.K3d points at the associated regulations, and 91.103 is the one the test loves. Read what it actually says, because the specific list is the answer:
- General duty. Each PIC shall, before beginning a flight, become familiar with all available information concerning that flight.
- For a flight not in the vicinity of an airport, and for any flight under IFR: weather reports and forecasts, fuel requirements, alternatives available if the planned flight cannot be completed, and any known traffic delays advised by ATC.
- For any flight: runway lengths at airports of intended use, and the takeoff and landing distance data in the approved AFM — or, if that data is not published, other reliable information appropriate to the aircraft, using airport elevation and runway slope, aircraft gross weight, and wind and temperature.
Two traps. First, the weather-and-alternates paragraph applies to flights not in the vicinity of an airport, so a local pattern flight is not excused from the runway-length and distance-data paragraph, which applies to any flight. Second, "all available information" is not satisfied by a phone glance at one radar image; NOTAMs, TFRs, and the Chart Supplement are available information (Sections 4.4 and 8.4).
The preflight inspection — what, why, and how you would spot it
PA.II.A.K3 breaks the inspection into which items to inspect, the reasons for checking each item, how to detect possible defects, and the associated regulations. Most candidates can recite a sequence; the ACS wants the reason. Use the AFM/POH checklist for that make and model, not a generic card, because the manufacturer's list reflects that airplane's known failure points.
| Item | Why you check it | What a defect looks like |
|---|---|---|
| Fuel quantity, visually at the filler | Gauges are required by 91.205 but are only required to be accurate at empty; fuel exhaustion and starvation remain leading causes of engine-failure accidents | Level well below the tab or last known fueling; a fuel receipt that does not match the tank |
| Fuel sumps — every drain, every tank, plus the gascolator | Water settles to the low point; the wrong grade or jet fuel will destroy the engine | Clear beads or a separate layer at the bottom; wrong color for the grade (100LL is blue); a sweaty, kerosene smell |
| Oil quantity against the AFM minimum for flight | Below minimum, cooling and lubrication margins disappear on a hot climb | Level below the marked minimum; oil streaks aft of the cowling or on the belly |
| Control surfaces, hinges, and linkage | A jammed or disconnected control is unrecoverable in flight | Excess play, missing cotter pins or safety wire, cracked hinge brackets, dented skins |
| Pitot cover removed; pitot and static ports clear | A blocked pitot or static port gives false airspeed and altitude (Section 12.1) | Cover still installed, insect nest, tape or wax over the static port |
| Fuel vents clear | A blocked vent creates a vacuum and starves the engine in cruise | Insect nests, crushed vent tube |
| Stall warning | Your only aerodynamic warning before the buffet (Section 9.2) | No horn or light with suction applied and master on |
| Propeller and spinner | Nicks are stress risers that grow into fatigue cracks | Nicks, gouges, cracks in the spinner or its backplate, oil at the hub |
| Tires, brakes, struts | Directional control on the roll and the ability to stop | Cord showing, flat spots, hydraulic wetness at the caliper, a flat strut |
| Tie-downs, chocks, gust locks, cowl plugs | Every one of them has caused a departure accident when left in place | Anything still attached to the airplane |
| Antennas, static wicks, windscreen | Communication, navigation, and the ability to see | Bent or missing antennas, crazed or oil-filmed windscreen |
How to detect a defect (PA.II.A.K3c) is a discipline, not a list: compare against how the airplane looked last time, follow oil and hydraulic streaks upstream to their source, press and wiggle anything meant to be rigid, and treat anything you cannot explain as a discrepancy until a mechanic explains it. Frost, snow, or ice on the lifting surfaces is a stop item — Section 7.2 explains why even a thin layer of frost can cost enough lift to prevent a safe takeoff.
Under 14 CFR 91.103, which item must a private pilot review before a 20-minute local flight that stays in the traffic pattern?
A rental airplane has a fresh annual inspection signed off yesterday. During preflight the pilot finds a fuel vent tube crushed closed. Which statement matches 14 CFR 91.7?
ACS Task II.A asks the applicant for the reason each preflight item is checked. Why is the fuel visually verified at the filler neck rather than read from the gauge?