kopik
Create
Aviation & dronesVerified by Kopik: Official sources reviewed and answers tested by Kopik

Control cable inspection and turnbuckle safetying: FAA AC 43.13-1B rules

Control cables wear where nobody looks: over pulleys, through fair-leads and near swaged fittings. The assistant explains the inspection and replacement criteria and the turnbuckle rules of AC 43.13-1B, Chapter 7.

Ask your question

Free account required

Each question stands alone · 1 free a month, then with a subscription.

Answers are written by a language model solely from this base's documents, with numbered sources. They can be wrong and aren't legal, medical or financial advice: check the sources before any important decision.

Finding broken wires and corrosion

All control cables must be inspected for broken wires at each annual or 100-hour inspection. Critical fatigue areas are where the cable runs over, under or around a pulley, sleeve or fair-lead, any section that is flexed or rubbed, and any point within 1 foot of a swaged-on fitting.

In these areas, pass a cloth along the cable: it snags on broken wires. Some breaks only show as a hairline crack, so a visual check is still needed.

If the surface is corroded, relieve tension and open the cable by reverse twisting to look inside. Corrosion on the interior strands constitutes failure and the cable must be replaced. With no internal corrosion, remove loose rust with a clean, dry, coarse-weave rag or fiber brush, never metallic wool or solvents, then apply MIL-C-16173 grade 4 compound sparingly.

Turnbuckles and their safetying

Both threaded terminals should be screwed into the barrel an equal amount, with no more than three threads exposed on either side. On initial installation, terminals should not be screwed in more than four threads inside the barrel. Turnbuckles with distorted or bent threads should be replaced.

Safety each turnbuckle with safety wire, using the double-wrap (preferred) or single-wrap method, or with an approved device meeting TSO-C21. Safety wire must not be reused, and the wire ends are wrapped at least four times around the shank.

Frequently asked questions

When must a cable be replaced regardless of broken wires?

AC 43.13-1B says to replace any cable with a popped core or loose strands regardless of wear or broken wires. Nylon-jacketed cable with cracks or necking down of the jacket must also be replaced.

Why is a straightened kink still a problem?

A kink disturbs the relative adjustment between strands, creating unequal tension and excessive wear. Even if it looks slight once straightened, the cable cannot give maximum service and should be replaced.

What should I check on pulleys?

Look for roughness, sharp edges and foreign material in the grooves, and check bearings for lubrication, smooth rotation and flat spots. Keep pulleys aligned so the cable does not ride on the flanges, and check brackets and guards for damage and security.

For developers and agents

Embed / API / MCP

Connect this base to Claude, Cursor, ChatGPT or your own app. Each API or MCP request costs €0.10, charged to your Kopik credit (not charged if nothing is found). You need an API key: create one from your dashboard.

MCP for your agents

This base's MCP server URL (tools ask_base and search_base):

MCP URL
https://kopik.io/api/mcp?base=us-faa-aircraft-repair-ac43-13
Claude Code, Cursor and other clients
Claude Code
claude mcp add --transport http kopik-us-faa-aircraft-repair-ac43-13 "https://kopik.io/api/mcp?base=us-faa-aircraft-repair-ac43-13" --header "Authorization: Bearer kpk_…"
JSON config (mcpServers)
{
  "mcpServers": {
    "kopik-us-faa-aircraft-repair-ac43-13": {
      "url": "https://kopik.io/api/mcp?base=us-faa-aircraft-repair-ac43-13",
      "headers": {
        "Authorization": "Bearer kpk_…"
      }
    }
  }
}

REST API for your apps

mode is "answer" (written answer + sources) or "passages" (raw passages only). Add an optional maxPriceCents to cap the price: if the base costs more, the call is refused and nothing is charged.

curl
curl -X POST https://kopik.io/api/v1/bases/us-faa-aircraft-repair-ac43-13/query \
  -H "Authorization: Bearer kpk_…" \
  -H "Content-Type: application/json" \
  -d '{"question": "Your question here", "mode": "answer"}'

Getting started

  1. Create a key in your dashboard and top up your credit.
  2. Replace kpk_… with your key.
  3. Full details (responses, errors, JS and Python examples): developer docs.