diff --git a/App/app/(portal)/crewing/applications/actions.ts b/App/app/(portal)/crewing/applications/actions.ts
index 8abf91c..6baf102 100644
--- a/App/app/(portal)/crewing/applications/actions.ts
+++ b/App/app/(portal)/crewing/applications/actions.ts
@@ -115,6 +115,16 @@ export async function advanceStage(id: string, action: ApplicationAction): Promi
   if (!transition) return { error: `Cannot ${action} from ${app.stage}` };
   if (!canPerformAction(app.stage, action, g.role)) return { error: "Unauthorized" };
 
+  // C5 (spec §5.1 / Epic C5 AC1): at least one reference must be recorded before
+  // leaving the COMPETENCY_AND_REFERENCES stage. The merged competency+references
+  // gate is completed by `verify_competency`.
+  if (action === "verify_competency") {
+    const references = await db.referenceCheck.count({ where: { applicationId: id } });
+    if (references === 0) {
+      return { error: "Record at least one reference check before completing competency & references" };
+    }
+  }
+
   await db.application.update({
     where: { id },
     data: {
@@ -207,6 +217,33 @@ export async function verifyDocuments(formData: FormData): Promise<ActionResult>
   const d = parsed.data;
   const crewMemberId = app.crewMember.id;
 
+  // C3 (spec §5.1 / Epic C3 AC1): block advancement when a mandatory document for
+  // the seat's rank is EXPIRED.
+  // Scope note (documented limitation): seafarer documents are collected on the
+  // crew profile *after* onboarding (Phase 4a) — during the pipeline a candidate
+  // usually has none on file, so a hard "missing document" block would stall the
+  // whole funnel. We therefore gate on what is available (expiry of documents the
+  // candidate already holds); the "all required documents present" check is
+  // enforced post-onboarding in the verification queue (§8.11). Once careers
+  // intake (A2) uploads documents pre-onboarding, tighten this to also require
+  // presence of every mandatory docType.
+  const reqRank = await db.requisition.findUnique({ where: { id: app.requisition.id }, select: { rankId: true } });
+  if (reqRank) {
+    const [required, candidateDocs] = await Promise.all([
+      db.rankDocRequirement.findMany({ where: { rankId: reqRank.rankId, isMandatory: true }, select: { docType: true } }),
+      db.seafarerDocument.findMany({ where: { crewMemberId }, select: { docType: true, expiryDate: true } }),
+    ]);
+    const requiredTypes = new Set(required.map((r) => r.docType));
+    const now = new Date();
+    const expired = candidateDocs.filter((doc) => requiredTypes.has(doc.docType) && doc.expiryDate && doc.expiryDate < now);
+    if (expired.length > 0) {
+      return { error: `Cannot verify documents — a required document is expired: ${expired.map((doc) => doc.docType).join(", ")}` };
+    }
+  }
+  // C4 (experience check) is deferred: the Requisition has no min-experience
+  // criteria field yet (see Epic A2 AC1 / wiki Tech-Debt). Once that lands, compare
+  // the candidate's ExperienceRecord total against it here and flag a shortfall.
+
   await db.$transaction(async (tx) => {
     // Capture bank / EPF (PII — encryption deferred to Phase 4).
     await tx.bankDetail.upsert({
diff --git a/App/tests/integration/applications.test.ts b/App/tests/integration/applications.test.ts
index 5299dfe..cd485b5 100644
--- a/App/tests/integration/applications.test.ts
+++ b/App/tests/integration/applications.test.ts
@@ -69,6 +69,7 @@ afterEach(async () => {
   await db.salaryStructure.deleteMany({});
   await db.applicationGate.deleteMany({});
   await db.referenceCheck.deleteMany({});
+  await db.seafarerDocument.deleteMany({});
   await db.application.deleteMany({});
   await db.bankDetail.deleteMany({});
   await db.epfDetail.deleteMany({});
@@ -191,6 +192,42 @@ describe("interview waiver (ex-hands, R2)", () => {
   });
 });
 
+describe("vetting gates (C3/C5)", () => {
+  it("blocks completing competency & references until a reference is recorded (C5)", async () => {
+    const { applicationId } = await newApplication();
+    as(manningId, "MANNING");
+    await advanceStage(applicationId, "start_competency"); // → COMPETENCY_AND_REFERENCES
+    // No reference recorded yet → cannot advance.
+    expect("error" in (await advanceStage(applicationId, "verify_competency"))).toBe(true);
+    expect((await db.application.findUniqueOrThrow({ where: { id: applicationId } })).stage).toBe("COMPETENCY_AND_REFERENCES");
+    // Record one → now it advances.
+    await recordReferenceCheck(fd({ applicationId, refereeName: "Capt. Rao", outcome: "positive" }));
+    expect("ok" in (await advanceStage(applicationId, "verify_competency"))).toBe(true);
+    expect((await db.application.findUniqueOrThrow({ where: { id: applicationId } })).stage).toBe("DOC_VERIFICATION");
+  });
+
+  it("blocks document verification when a required document on file is expired (C3)", async () => {
+    const { applicationId, requisitionId, crewMemberId } = await newApplication();
+    await setStage(applicationId, "DOC_VERIFICATION");
+    const reqRank = (await db.requisition.findUniqueOrThrow({ where: { id: requisitionId } })).rankId;
+    await db.rankDocRequirement.upsert({
+      where: { rankId_docType: { rankId: reqRank, docType: "MEDICAL_FITNESS" } },
+      update: { isMandatory: true },
+      create: { rankId: reqRank, docType: "MEDICAL_FITNESS", isMandatory: true },
+    });
+    await db.seafarerDocument.create({ data: { crewMemberId, docType: "MEDICAL_FITNESS", expiryDate: new Date("2020-01-01") } });
+
+    as(manningId, "MANNING");
+    expect("error" in (await verifyDocuments(fd({ applicationId })))).toBe(true);
+    expect((await db.application.findUniqueOrThrow({ where: { id: applicationId } })).stage).toBe("DOC_VERIFICATION");
+
+    // Renew the document → advancement proceeds.
+    await db.seafarerDocument.updateMany({ where: { crewMemberId }, data: { expiryDate: new Date("2030-01-01") } });
+    expect("ok" in (await verifyDocuments(fd({ applicationId })))).toBe(true);
+    expect((await db.application.findUniqueOrThrow({ where: { id: applicationId } })).stage).toBe("SALARY_AGREEMENT");
+  });
+});
+
 describe("rejection", () => {
   it("MPO rejects from a mid stage", async () => {
     const { applicationId } = await newApplication();