CAP 1404 — Airspace Infringements: review and actions (Edition 6, 20 June 2023) is the CAA's published process document. It describes how allegations are evaluated, what factors are weighed, and what outcomes are available. Understanding it is essential to framing your response effectively.
CAP 1404 prominently invokes "Just Culture" — a principle from aviation safety science in which people are not punished for honest mistakes. The CAA states that investigations seek to establish facts, not apportion blame. CAP 1404 Ed. 6, p.5
In practice, a significant number of pilots — including professional pilots and flight examiners — have reported a different experience. A 2020 investigation by Pilot magazine, based on multiple complainants, found: Pilot magazine, Nov 2020
The CAA's own fact file (CAP 2125) acknowledges, verbatim, that pilots ask: "How can the CAA justify saying they follow Just Culture and then treat infringing pilots in the way they do?" — indicating this criticism is well known to the authority itself.
You are entitled to hold the CAA to the standards it publicly commits to. The obligations set out in CAP 1404 — to disclose the evidence, to explain the rationale, to accept your submissions — are not aspirational. They are what the CAA says it will do. Demand it.
Despite the concerns above, the statistics show that serious sanctions remain rare. On average across all reviewed infringements: 69% receive educational material only; 22% undertake online tutorial or AIAC; 7% undertake additional flight training; 2% face provisional suspension; <0.4% face prosecution; <0.025% face full suspension or revocation. CAP 1404 Ed. 6, p.4
The strongest case for challenging the evidence arises where the alleged infringement is small. In those cases the ICG's first question — "can we confirm an infringement occurred?" — may genuinely be unanswerable on the data available.
The ANSP (usually NATS) submits a Mandatory Occurrence Report (MOR) to the CAA detailing the apparent infringement. Separately, in serious cases, the ANSP may also file a CA939 — an Alleged Breach of Air Navigation Legislation (ABANL) — directly with the CAA's Investigations and Enforcement Team. The MOR route and the ABANL route are distinct and have different implications. [CAP 1404 Ed. 6, p.7]
NATS will often ask you to complete a questionnaire via airspacesafety.com. It is presented as a two-way learning exercise, but CAP 1404 makes clear that the information you provide is shared with the CAA and forms part of the evidence considered by the ICG. Failure to respond also has consequences — the ICG will base its decision only on the ANSP's evidence. If you intend to challenge the technical evidence, review the questionnaire carefully before completing it and consider seeking advice first. [CAP 1404 Ed. 6, pp.7–8]
Cases with any of three characteristics are referred to the ICG: (1) safety impact such as loss of separation or ATC avoiding action; (2) safety intervention measures applied (runway holds, vectors, holds); (3) pilot has a previous infringement decision within the preceding 2 years. The ICG is a multi-disciplinary panel from across the CAA including the General Aviation Unit, Investigations and Enforcement, Airspace Regulation, Pilot Licensing, ATM, and the Military Aviation Authority. [CAP 1404 Ed. 6, pp.9–10]
CAP 1404 Edition 6 (p.11) lists the specific questions the ICG must address. These are directly relevant to how you frame your response.
The first and most important question. The ICG cannot proceed to remedial action unless it can confirm the infringement happened. This is where technical accuracy arguments belong. If the alleged penetration margin is within the accuracy tolerance of the surveillance system, the answer should be "not confirmed". Your response should make this argument clearly and with reference to the specific figures in CAP 670 and the EUROCONTROL specification. [CAP 1404 Ed. 6, p.11]
Loss of radar separation from other traffic is a significant aggravating factor. If no separation was lost — because your aircraft was alone in the area or other traffic was well clear — address this directly in your response. The absence of a separation event is relevant both to severity classification and to the question of whether a genuine hazard existed. [CAP 1404 Ed. 6, p.11]
The ICG considers whether ATC had to give avoiding action, break off approaches, hold departures, or vector other aircraft. If no such measures were needed, note this in your response. Furthermore: if the controller did not identify a genuine hazard in real time and did not react to it, this may indicate the track data was not obviously showing a clear boundary penetration — consistent with the data being at the margins of the system's accuracy. [CAP 1404 Ed. 6, p.11]
The ICG explicitly asks whether you used a VFR moving map. A "yes" answer, supported by a GPS track log showing your aircraft consistently outside the boundary, is highly relevant evidence. It demonstrates both good airmanship and provides independent positional data substantially more accurate than ATC radar. Preserve your EFB or GPS track log immediately. [CAP 1404 Ed. 6, p.11]
The ICG expressly weighs your attitude and understanding. A professional, factual, evidence-based response that engages seriously with the technical issues — without being dismissive of airspace safety in general — is exactly the right approach. You can acknowledge the importance of airspace compliance while firmly maintaining that the specific data in your case does not establish an infringement. Challenging evidence is not the same as being uncooperative. [CAP 1404 Ed. 6, p.11]
A previous infringement is only considered relevant if the CAA's decision on that earlier event falls within 2 years of the current incident date. This is measured from the date of the CAA's decision on the previous event, not the date of the previous incident itself. If you have an earlier infringement but the CAA's decision on it was more than 2 years before the current alleged incident, it should not escalate the current case. [CAP 1404 Ed. 6, p.9]
If the ICG confirms an infringement occurred, it classifies severity and determines proportionate action. [CAP 1404 Ed. 6, pp.12–16]
No safety intervention measures required. No previous decision within 2 years.
Safety interventions were needed, or pilot has a relevant previous decision.
Flight safety was compromised, or more than one previous infringement within the window.
Since CAP 1404 Edition 5 (August 2021), pilots have the right to request a review of a provisional suspension decision. You must be notified of this right. The review process is set out in CAP 393, Section 6 — General Appeals Process. The technical accuracy arguments in this guide are directly relevant: if the evidence on which the suspension is based falls within radar tolerance, the suspension may not be sustainable. Seek professional representation immediately if you receive a provisional suspension notice. [CAP 1404 Ed. 6, pp.14–15]
CAP 1404 Edition 6 (p.5) sets out specific obligations the CAA takes on under Just Culture principles:
Submit your SRG1605 form (available on the CAA forms page) alongside your UK GDPR Subject Access Request for the radar data. These are complementary requests covering different records.