# ATPL.app > Build your aviation theory knowledge with focused question practice, mock exams, and practical study guides from ATPL. ## Blog - [Review the reasoning, not just the result](https://atpl.app/blog/review-the-reasoning): Make your question practice more useful by reviewing uncertain correct answers, identifying gaps in your reasoning, and choosing a clear next study objective. ## Changelog - [A new home for aviation theory](https://atpl.app/changelog/website-preview): The first preview of ATPL’s public website brings together a knowledge hub, study guides, product help, blog articles, and a changelog. ## Guides - [Pilot guides](https://atpl.app/guides): Licensing routes and training decisions, organised by the system you will fly under and the qualification you want to work towards. - [How to build an ATPL study plan](https://atpl.app/guides/atpl-study-plan): Turn your aviation theory syllabus into a practical study routine, with focused objectives, question practice, review time, and a simple error log. ### EASA - [Getting an EASA PPL(A)](https://atpl.app/guides/easa/ppl-a): Learn what you need for an EASA private pilot licence for aeroplanes, including medical requirements, exams, flight training and the licence application. ### FAA - [Pilot guides for the United States](https://atpl.app/guides/faa): FAA certificate pathways, with aircraft category, class and additional ratings identified separately. ### UK - [Getting a UK PPL(A)](https://atpl.app/guides/uk/ppl-a): Learn what you need for a UK Part-FCL private pilot licence for aeroplanes, including medical requirements, exams, flight training and the CAA application. ## Help - [ATPL help](https://atpl.app/help): Get started with the ATPL study app, learn the difference between study and mock modes, and find your completed sessions for review. - [Getting started with ATPL](https://atpl.app/help/getting-started): Learn how to start an ATPL study session, choose study or mock mode, answer questions, and return to completed sessions for review. ## Knowledge - [Aviation theory knowledge hub](https://atpl.app/knowledge): Explore aviation theory by subject, with clear explanations of meteorology, principles of flight, and general navigation, plus related study guides. ### Meteorology - [Aviation meteorology](https://atpl.app/knowledge/meteorology): Study aviation meteorology through pressure, moisture, stability and weather systems, with examples that separate observations, forecasts and assumptions. - [How density altitude affects aircraft performance](https://atpl.app/knowledge/meteorology/density-altitude): Understand density altitude, how it differs from pressure altitude, and why a hotter day changes aircraft performance. Work through a clear two-day example. - [Why air pressure falls with altitude](https://atpl.app/knowledge/meteorology/pressure-and-altitude): Learn why atmospheric pressure falls with altitude, how an altimeter converts pressure into a reading, and why its setting and temperature matter in flight. ### Principles of flight - [Principles of flight](https://atpl.app/knowledge/principles-of-flight): Connect airflow, lift, drag, stability and manoeuvres in principles of flight. Check worked examples by drawing forces and stating what stays constant. - [Angle of attack vs pitch angle](https://atpl.app/knowledge/principles-of-flight/angle-of-attack): Understand angle of attack vs pitch angle with a clear diagram and worked examples. Learn why a nose-down aircraft can still have a positive angle of attack. - [Induced drag vs parasite drag](https://atpl.app/knowledge/principles-of-flight/induced-and-parasite-drag): Compare induced drag vs parasite drag, understand why their speed trends differ, and read a total-drag curve with clear assumptions and a worked example. ### General navigation - [General navigation](https://atpl.app/knowledge/general-navigation): Connect positions, charts, time, speed and wind in general navigation. Use worked examples to check units, reference directions and small-angle estimates. - [Calculating wind correction angle](https://atpl.app/knowledge/general-navigation/wind-correction-angle): Calculate wind correction angle from course, wind and true airspeed. Follow worked examples, check the correction direction and understand the method’s limits. - [Heading vs track](https://atpl.app/knowledge/general-navigation/heading-and-track): Understand heading vs track and course with a wind diagram and a worked example. See why pointing the nose north does not always take you north over the ground. ## RSS Feeds - [ATPL.app — Blog](https://atpl.app/blog/rss.xml) - [ATPL.app — Changelog](https://atpl.app/changelog/rss.xml) ## Agent skills - [atpl-app](https://atpl.app/.well-known/agent-skills/atpl-app/SKILL.md): Read the ATPL.app docs instead of answering from memory. Build your aviation theory knowledge with focused question practice, mock exams, and practical study guides from ATPL. Use when a task involves ATPL.app: how it works, how to set it up or configure it, or its API. ## Agent resources - [llms-full.txt](https://atpl.app/llms-full.txt): The full Markdown of every page in one file. - [Page Markdown](https://atpl.app/index.md): Append `.md` to any page URL to fetch that page as raw Markdown. - [JSON API](https://atpl.app/api/docs/pages.json): Page index of the JSON docs API; each entry links the page's JSON and Markdown forms. Described by the OpenAPI document at https://atpl.app/openapi.json. - [MCP server](https://atpl.app/mcp): Streamable HTTP Model Context Protocol server with search_docs, get_page, list_pages, and get_navigation tools, plus every page as a resource. Discovery document: https://atpl.app/.well-known/mcp.json - [Agent skills](https://atpl.app/.well-known/agent-skills/index.json): Agent Skills discovery index of the skills this site publishes. - [API catalog](https://atpl.app/.well-known/api-catalog): RFC 9727 linkset of the APIs documented here. - [AI catalog](https://atpl.app/.well-known/ai-catalog.json): ARD manifest of the agent-facing resources on this site (MCP server, skills, APIs). - [agent-readability.json](https://atpl.app/agent-readability.json): Manifest of every agent-facing artifact on this site. - [Sitemap](https://atpl.app/sitemap.xml): Every indexable page URL with its last-modified date.