The visual preflight assessment is an important step in mitigating airplane flight hazards. The purpose of the preflight assessment is to ensure that the airplane meets regulatory airworthiness standards and is in a safe mechanical condition prior to flight. The term “airworthy” means that the aircraft and its component parts meet the airplane’s type design or is in a properly altered configuration and is in a condition for safe operation. The inspection has two parts and involves the pilot inspecting the airplane’s airworthiness status and a visual preflight inspection of the airplane following the AFM/POH to determine the required items for inspection. [Figures 1 through 3] The owner/operator is primarily responsible for maintenance, but the pilot is (solely) responsible for determining the airworthiness (and/or safety) of the airplane for flight.
|Figure 1. Pilots must view the aircraft’s maintenance logbook prior to flight to ensure the aircraft is safe to fly|
|Figure 2. A visual inspection of the aircraft before flight is an important step in mitigating airplane flight hazards|
|Figure 3. Airplane Flight Manuals (AFM) and the Pilot Operating Handbook (POH) for each individual aircraft explain the required items for inspection|
Each airplane has a set of logbooks that include airframe and engine and, in some cases, propeller and appliance logbooks, which are used to record maintenance, alteration, and inspections performed on a specific airframe, engine, propeller, or appliance. It is important that the logbooks be kept accurate and secure but available for inspection. Airplane logbooks are not required, nor is it advisable, to be kept in the airplane. It should be a matter of procedure by the pilot to inspect the airplane logbooks or a summary of the airworthy status prior to flight to ensure that the airplane records of maintenance, alteration, and inspections are current and correct. [Figure 4] The following is required:
- Annual inspection within the preceding 12-calendar months (Title 14 of the Code of Federal Regulations (14 CFR) part 91, section 91.409(a))
- 100-hour inspection, if the aircraft is operated for hire (14 CFR part 91, section 91.409(b))
- Transponder certification within the preceding 24-calendar months (14 CFR part 91, section 91.413)
- Static system and encoder certification, within the preceding 24-calendar months, required for instrument flight rules (IFR) flight in controlled airspace (14 CFR part 91, section 91.411)
- 30-day VHF omnidirectional range (VOR) equipment check required for IFR flight (14 CFR part 91, section 91.171)
- Emergency locator transmitter (ELT) inspection within the last 12 months (14 CFR part 91, section 91.207(d))
- ELT battery due (14 CFR part 91, section 91.207(c))
- Current status of life limited parts per Type Certificate Data Sheets (TCDS) (14 CFR part 91, section 91.417)
- Status, compliance, logbook entries for airworthiness directives (ADs) (14 CFR part 91, section 91.417(a)(2)(v))
- Federal Aviation Administration (FAA) Form 337, Major Repair or Alteration (14 CFR part 91, section 91.417) • Inoperative equipment (14 CFR part 91, section 91.213)
|Figure 4. A sample airworthiness checklist used by pilots to inspect an aircraft|
A review determines if the required maintenance and inspections have been performed on the airplane. Any discrepancies must be addressed prior to flight. Once the pilot has determined that the airplane’s logbooks provide factual assurance that the aircraft meets its airworthy requirements, it is appropriate to visually inspect the airplane. The visual preflight inspection of the airplane should begin while approaching the airplane on the ramp. The pilot should make note of the general appearance of the airplane, looking for discrepancies such as misalignment of the landing gear and airplane structure. The pilot should also take note of any distortions of the wings, fuselage, and tail, as well as skin damage and any staining, dripping, or puddles of fuel or oils.
It must be determined by the pilot that the following documents are, as appropriate, on board, attached, or affixed to the airplane:
- Original Airworthiness Certificate (14 CFR part 91, section 91.203)
- Original Registration Certificate (14 CFR part 91, section 91.203)
- Radio station license for flights outside the United States or airplanes greater than 12,500 pounds (Federal Communications Commission (FCC) rule)
- Operating limitations, which may be in the form of an FAA-approved AFM/POH, placards, instrument markings, or any combination thereof (14 CFR part 91, section 91.9)
- Official weight and balance
- Compass deviation card (14 CFR part 23, section 23.1547)
- External data plate (14 CFR part 45, section 45.11)
Visual Preflight Assessment The inspection should start with the cabin door. If the door is hard to open or close, does not fit snugly, or the door latches do not engage or disengage smoothly, the surrounding structure, such as the door post, should be inspected for misalignment which could indicate structural damage. The visual preflight inspection should continue to the interior of the cabin or cockpit where carpeting should be inspected to ensure that it is serviceable, dry, and properly affixed; seats belts and shoulder harnesses should be inspected to ensure that they are free from fraying, latch properly, and are securely attached to their mounting fittings; seats should be inspected to ensure that the seats properly latch into the seat rails through the seat lock pins and that seat rail holes are not abnormally worn to an oval shape; [Figure 5] the windshield and windows should be inspected to ensure that they are clean and free from cracks, and crazing. A dirty, scratched, and/or a severely crazed window can result in near zero visibility due to light refraction at certain angles from the sun.
|Figure 5. Seats should be inspected to ensure that they are properly latched into the seat rails and checked for damage|
AFM/POH must be the reference for conducting the visual preflight inspection, and each manufacturer has a specified sequence for conducting the actions. In general, the following items are likely to be included in the AFM/POH preflight inspection:
- Master, alternator, and magneto switches are OFF
- Control column locks are REMOVED
- Landing gear control is DOWN
- Fuel selectors should be checked for proper operation in all positions, including the OFF position. Stiff fuel selectors or where the tank position is not legible or lacking detents are unacceptable.
- Trim wheels, which include elevator and may include rudder and aileron, are set for takeoff position.
- Avionics master OFF
- Circuit breakers checked IN
- Flight instruments must read correctly. Airspeed zero; altimeter when properly set to the current barometric setting should indicate the field elevation within 75 feet for IFR flight; the magnetic compass should indicate the airplane’s direction accurately; and the compass correction card should be legible and complete. For conventional wet magnetic compasses, the instrument face must be clear and the instrument case full of fluid. A cloudy instrument face, bubbles in the fluid, or a partially filled case renders the compass unusable. The vertical speed indictor (VSI) should read zero. If the VSI does not show a zero reading, a small screwdriver can be used to zero the instrument.The VSI is the only flight instrument that a pilot has the prerogative to adjust. All others must be adjusted by an FAA-certificated repairman or mechanic.
- Mechanical air-driven gyro instruments must be inspected for signs of hazing on the instrument face, which may indicate leaks.
- If the airplane has retractable gear, landing gear down and locked lights are checked green.
- Check the landing gear switch is DOWN, then turn the master switch to the ON position and fuel qualities must be noted on the fuel quantity gauges and compared to a visual inspection of the tank level. If so equipped, fuel pumps may be placed in the ON position to verify fuel pressure in the proper operating range.
- Other items may include checking that lights for both the interior and exterior airplane positions are operating and any annunciator panel checks.
Advanced avionics aircraft have specific requirements for testing Integrated Flight Deck (IFD) “glass-panel” avionics and supporting systems prior to flight. IFD’s are complex electronic systems typically integrating flight control, navigation and communication, weather, terrain, and traffic subsystems with the purpose to enhance a pilot’s situational awareness (SA), aeronautical decision-making (ADM), and single-pilot resource management (SRM) capability. Ground-based inspections may include verification that the flight deck reference guide is in the aircraft and assessable, system driven removal of “Xs” over engine indicators, pitot/static and attitude displays, testing of low level alarms, annunciator panels, setting of fuel levels, and verification that the avionics cooling fans, if equipped, are functional. [Figure 6] The AFM/POH specifies how these preflight inspections are to take place. Since an advanced avionics aircraft preflight checklist may be extensive, pilots should allow extra time for these aircraft to ensure that all items are properly addressed.
|Figure 6. Ground-based inspections include verification that “Xs” on the instrument display are displayed until the sensor activates|