Ice and rain protection

Five procedures.

Procedure 1 — Clean a pneumatic deicer boot (S3, R3)

1. Identify the approved cleaner from the boot manufacturer's instructions. Nothing else.
2. Remove loose dirt with clean water first.
3. Apply the cleaner as specified, working gently — no aggressive scrubbing and no abrasives.
4. Rinse and dry.
5. Apply the approved dressing where the manufacturer specifies one.
6. Inspect while you work: cuts, punctures, abrasion, lifting at the bond line, cracking.

Check — name the product before you open it. A general shop solvent will clean the boot and destroy it, and the damage appears weeks later (AF-L Concepts §2).

Procedure 2 — Inspect and operationally check a deicer boot (S2)

1. Inspect the boot surface and bond line — lifting at an edge is a finding.
2. Check air lines and connections for security and leaks.
3. Operate the system and watch: each boot inflates fully, in the correct sequence, and deflates cleanly and completely.
4. Time the cycle against the manual.
5. Check inflation pressure against the specification.

Check — watch the deflation, not just the inflation. A boot that inflates well and stays partly inflated is a permanent aerodynamic penalty and a sign of a suction or valve fault.

Procedure 3 — Inspect and check an electrically heated system (S1, S5, S6, S7)

1. Visual: element condition, connections, security, chafe, discoloration or burning at terminals.
2. Measure current with the system on, and compare against the expected value (GEN-A Procedures Procedure 3).
3. Or measure element resistance cold, against specification, with the circuit isolated.
4. Check the control and any thermostat or overheat protection functions.
5. On a heated windshield, check for delamination, discoloration and hot spots.

Check — measure, do not feel. A partially failed element still gets warm, and warmth is not evidence that it is producing its rated heat (AF-L Concepts §4).

Procedure 4 — Troubleshoot a heated pitot circuit (S4)

1. Predict: supply voltage, expected current, expected element resistance.
2. Confirm supply at the breaker and at the switch.
3. Voltage drop under load along the circuit — supply, switch, connector, element, ground.
4. The whole supply voltage across a break locates an open; volts across a connection locates resistance.
5. Check the ground. It is the most commonly overlooked half of the circuit.

Check — the drops must sum to the supply voltage. If they do not, an element you have not measured holds the missing volts (GEN-A Procedures Procedure 5).

Procedure 5 — Inspect a rain control system (S8, S9)

1. Wipers: blade condition, arm pressure, park position, and that the mechanism sweeps the specified area without contacting the frame.
2. Chemical systems: fluid level, nozzle condition, spray pattern.
3. Bleed-air rain removal: duct and nozzle condition, security.
4. Check for anything that could damage the transparency — a worn blade with exposed metal will scratch a windscreen in one pass.

Check — run the wipers dry only if the manual permits it. Dry operation damages both blade and transparency, and it is the fastest way to ruin a windscreen during an inspection.

The checks, collected

License

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