How do I install the Special Conditions skill?

Run npx skillmds@latest add ashfordeou/special-conditions in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Special Conditions safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Special Conditions?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Special Conditions free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under Apache-2.

Who published Special Conditions?

ashfordeOU (@ashfordeou) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Special Conditions by ashfordeou — Agent Skill

Name: Special Conditions
Author: ashfordeOU

Special Conditions

Use when you must determine whether a novel or unusual transport-category design feature needs a special condition under FAR 25.17 or CS-25.17 instead of being covered by the existing airworthiness standards: classify the feature from its novelty, existing coverage, and safety significance, then draft the special condition scope with the affected subject, the issue addressed, and the proposed means of compliance (analysis, test, simulation). Produces the special-condition verdict and the scoped content for the certification program. Trigger: special condition, novel design feature, fly-by-wire, envelope protection, unusual technology, new technology, means of compliance, FAR 25.17, CS 25.17.

ashfordeOU Updated Sep 17, 2026

File contents

Special Conditions (avionics/far-cs25/special-conditions)

Use when the task is the special-conditions decision for a transport airplane: whether a novel or unusual design feature is covered by the existing FAR-25 / CS-25 airworthiness standards or needs a special condition under 25.17, and what that special condition should contain.

Domain quick reference

FAR 25.17 / CS-25.17 let the certification authority issue special conditions when a novel or unusual design feature is not covered by the existing airworthiness standards.
The special condition states additional requirements for the feature and the means of compliance that demonstrate them.
Examples from certification history: fly-by-wire flight control with envelope protection, and novel composite wing structures.
A special condition is scoped per feature: affected subject, the issue addressed, and the proposed means of compliance (analysis, test, simulation).
This module reasons over categorical inputs (booleans and short text), so no physical quantities or unit conventions apply.

Workflow

Describe the feature: name, novelty (novel), coverage by an existing standard (existing_standard), and safety significance (safety_significant).
Classify with classify_feature: returns the verdict and the category from the rule table.
When the verdict is special-condition-required, scope the content with draft_scopes: subject area, issue, means of compliance.
Bring the draft scope to the certification authority for agreement on the requirement text and the means of compliance.

Pitfalls

Treating every new feature as needing a special condition when an existing standard already covers it.
Scoping a special condition (draft_scopes) for a feature the rule table classifies as covered: it raises ValueError.
Passing numbers or strings where booleans are expected, or omitting a required key: the module raises ValueError.
Confusing the special-conditions decision with the certification basis or the 25.1309 safety assessment (separate leaves).

Behavior contract (gate 3)

The classification and scoping logic is exercised by the gate 3 contract test: scripts/test_special_conditions_logic.py against scripts/special_conditions_logic.py (stdlib unittest, offline). Run: python3 scripts/test_special_conditions_logic.py

Compliance

FAR-25 is US government work (17 U.S.C. 105), quotable with citation; CS-25 reproduction authorised with source acknowledged (EASA). Paraphrase preferred per standards-map.yaml.
compliance: STANDARDS-REF, gated: false.

---name: special-conditionsdescription: Use when you must determine whether a novel or unusual transport-category design feature needs a special condition under FAR 25.17 or CS-25.17 instead of being covered by the existing airworthiness standards: classify the feature from its novelty, existing coverage, and safety significance, then draft the special condition scope with the affected subject, the issue addressed, and the proposed means of compliance (analysis, test, simulation). Produces the special-condition verdict and the scoped content for the certification program. Trigger: special condition, novel design feature, fly-by-wire, envelope protection, unusual technology, new technology, means of compliance, FAR 25.17, CS 25.17.license: Apache-2.0---# Special Conditions (avionics/far-cs25/special-conditions)Use when the task is the special-conditions decision for a transportairplane: whether a novel or unusual design feature is covered by theexisting FAR-25 / CS-25 airworthiness standards or needs a specialcondition under 25.17, and what that special condition should contain.## Domain quick reference- FAR 25.17 / CS-25.17 let the certification authority issue special conditions when a novel or unusual design feature is not covered by the existing airworthiness standards.- The special condition states additional requirements for the feature and the means of compliance that demonstrate them.- Examples from certification history: fly-by-wire flight control with envelope protection, and novel composite wing structures.- A special condition is scoped per feature: affected subject, the issue addressed, and the proposed means of compliance (analysis, test, simulation).- This module reasons over categorical inputs (booleans and short text), so no physical quantities or unit conventions apply.## Workflow1. Describe the feature: name, novelty (novel), coverage by an existing standard (existing_standard), and safety significance (safety_significant).2. Classify with classify_feature: returns the verdict and the category from the rule table.3. When the verdict is special-condition-required, scope the content with draft_scopes: subject area, issue, means of compliance.4. Bring the draft scope to the certification authority for agreement on the requirement text and the means of compliance.## Pitfalls- Treating every new feature as needing a special condition when an existing standard already covers it.- Scoping a special condition (draft_scopes) for a feature the rule table classifies as covered: it raises ValueError.- Passing numbers or strings where booleans are expected, or omitting a required key: the module raises ValueError.- Confusing the special-conditions decision with the certification basis or the 25.1309 safety assessment (separate leaves).## Behavior contract (gate 3)The classification and scoping logic is exercised by the gate 3contract test: scripts/test_special_conditions_logic.py againstscripts/special_conditions_logic.py (stdlib unittest, offline).Run:python3 scripts/test_special_conditions_logic.py## Compliance- FAR-25 is US government work (17 U.S.C. 105), quotable with citation; CS-25 reproduction authorised with source acknowledged (EASA). Paraphrase preferred per standards-map.yaml.- compliance: STANDARDS-REF, gated: false.

Frequently asked questions