diff --git a/src/features/online-board/components/BoardDetailsHeader/DetailsHeaderBadge.test.tsx b/src/features/online-board/components/BoardDetailsHeader/DetailsHeaderBadge.test.tsx
index 956de2ad..b6a318a3 100644
--- a/src/features/online-board/components/BoardDetailsHeader/DetailsHeaderBadge.test.tsx
+++ b/src/features/online-board/components/BoardDetailsHeader/DetailsHeaderBadge.test.tsx
@@ -88,6 +88,13 @@ describe("DetailsHeaderBadge", () => {
     expect(screen.getByText("SU 0022")).toBeTruthy();
   });
 
+  it("TIRREDESIGN-13: renders suffix in primary flight number", () => {
+    const flight = makeDirect();
+    flight.flightId = { ...flight.flightId, flightNumber: "0038", suffix: "D" };
+    render(<DetailsHeaderBadge flight={flight} locale="ru" />);
+    expect(screen.getByText("SU 0038D")).toBeTruthy();
+  });
+
   it("renders operator-logo", () => {
     render(<DetailsHeaderBadge flight={makeDirect()} locale="ru" />);
     expect(screen.getByTestId("operator-logo")).toBeTruthy();
diff --git a/src/features/online-board/components/BoardDetailsHeader/DetailsHeaderBadge.tsx b/src/features/online-board/components/BoardDetailsHeader/DetailsHeaderBadge.tsx
index 699ee772..d13dcde9 100644
--- a/src/features/online-board/components/BoardDetailsHeader/DetailsHeaderBadge.tsx
+++ b/src/features/online-board/components/BoardDetailsHeader/DetailsHeaderBadge.tsx
@@ -39,7 +39,7 @@ export const DetailsHeaderBadge: FC<DetailsHeaderBadgeProps> = ({
 }) => {
   const { t } = useTranslation();
   const codeshareLegs = getCodeshareLegs(flight);
-  const primaryNumber = `${flight.flightId.carrier} ${flight.flightId.flightNumber}`;
+  const primaryNumber = `${flight.flightId.carrier} ${flight.flightId.flightNumber}${flight.flightId.suffix ?? ""}`;
   const carrier = operatingCarrier(flight.operatingBy) ?? flight.flightId.carrier;
 
   return (
diff --git a/src/features/online-board/components/FlightsMiniList/FlightsMiniListItem.test.tsx b/src/features/online-board/components/FlightsMiniList/FlightsMiniListItem.test.tsx
index 04e0d163..cdc5aebf 100644
--- a/src/features/online-board/components/FlightsMiniList/FlightsMiniListItem.test.tsx
+++ b/src/features/online-board/components/FlightsMiniList/FlightsMiniListItem.test.tsx
@@ -60,6 +60,15 @@ describe("FlightsMiniListItem", () => {
     expect(screen.getByText(/SU\s*0022/)).toBeTruthy();
   });
 
+  it("TIRREDESIGN-13: renders suffix in flight number", () => {
+    const flight = makeDirectFlight({
+      id: "SU0038D-20260514",
+      flightId: { carrier: "SU", flightNumber: "0038", suffix: "D", date: "20260514" },
+    });
+    render(<FlightsMiniListItem flight={flight} isSelected={false} lang="ru" />);
+    expect(screen.getByText(/SU\s*0038D/)).toBeTruthy();
+  });
+
   it("renders departure and arrival times", () => {
     const flight = makeDirectFlight();
     render(<FlightsMiniListItem flight={flight} isSelected={false} lang="ru" />);
diff --git a/src/features/online-board/components/FlightsMiniList/FlightsMiniListItem.tsx b/src/features/online-board/components/FlightsMiniList/FlightsMiniListItem.tsx
index f8771fb3..9739fa81 100644
--- a/src/features/online-board/components/FlightsMiniList/FlightsMiniListItem.tsx
+++ b/src/features/online-board/components/FlightsMiniList/FlightsMiniListItem.tsx
@@ -127,14 +127,14 @@ export const FlightsMiniListItem = forwardRef<HTMLAnchorElement, FlightsMiniList
         <div className="mini-list__flight-number">
           {(() => {
             const childIds = (flight as typeof flight & {
-              _childFlightIds?: { carrier: string; flightNumber: string }[];
+              _childFlightIds?: { carrier: string; flightNumber: string; suffix?: string }[];
             })._childFlightIds;
             if (childIds && childIds.length > 1) {
               return childIds
-                .map((c) => `${c.carrier} ${c.flightNumber}`)
+                .map((c) => `${c.carrier} ${c.flightNumber}${c.suffix ?? ""}`)
                 .join(", ");
             }
-            return `${flight.flightId.carrier} ${flight.flightId.flightNumber}`;
+            return `${flight.flightId.carrier} ${flight.flightId.flightNumber}${flight.flightId.suffix ?? ""}`;
           })()}
           <span
             className={`mini-list__status-icon ${iconColor}`}
diff --git a/src/features/online-board/components/OnlineBoardDetailsPage.test.tsx b/src/features/online-board/components/OnlineBoardDetailsPage.test.tsx
index a95f1052..d5940eeb 100644
--- a/src/features/online-board/components/OnlineBoardDetailsPage.test.tsx
+++ b/src/features/online-board/components/OnlineBoardDetailsPage.test.tsx
@@ -173,6 +173,29 @@ describe("OnlineBoardDetailsPage", () => {
     expect(screen.getAllByText("SU 100").length).toBeGreaterThanOrEqual(1);
   });
 
+  it("TIRREDESIGN-13: renders suffix in the details page flight number", () => {
+    const suffixFlight = {
+      ...mockFlight,
+      id: "SU0038D-20260514",
+      flightId: { carrier: "SU", flightNumber: "0038", suffix: "D", date: "20260514" },
+    } as IDirectFlight;
+    mockState = {
+      flight: suffixFlight,
+      allFlights: [suffixFlight],
+      daysOfFlight: ["20260514"],
+      loading: false,
+      error: null,
+    };
+    render(
+      <OnlineBoardDetailsPage
+        flightId={{ carrier: "SU", flightNumber: "0038", suffix: "D", date: "20260514" }}
+        locale="ru"
+        canonicalOrigin="https://www.aeroflot.ru"
+      />,
+    );
+    expect(screen.getAllByText("SU 0038D").length).toBeGreaterThanOrEqual(1);
+  });
+
   it("renders loading skeleton", () => {
     mockState = { flight: null, allFlights: [], daysOfFlight: [], loading: true, error: null };
     render(<OnlineBoardDetailsPage flightId={mockFlightId} locale="ru" canonicalOrigin="https://www.aeroflot.ru" />);
@@ -440,6 +463,20 @@ describe("OnlineBoardDetailsPage", () => {
       expect(link?.getAttribute("href")).toContain("/ru/onlineboard/flight/SU1234-20260515");
     });
 
+    it("TIRREDESIGN-13: flight context keeps suffix in breadcrumb back URL", () => {
+      mockSearchParamsInstance = new URLSearchParams("request=onlineboard-flight-SU0038D-20260514");
+      const { container } = render(
+        <OnlineBoardDetailsPage
+          flightId={mockFlightId}
+          locale="ru"
+          canonicalOrigin="https://example.com"
+        />,
+      );
+      const link = getCrumbLink(container, "BREADCRUMBS.FLIGHT-NUMBER");
+      expect(link).toBeTruthy();
+      expect(link?.getAttribute("href")).toContain("/ru/onlineboard/flight/SU0038D-20260514");
+    });
+
     it("route context → leaf 'Маршрут: …' linking back to /route/", () => {
       mockSearchParamsInstance = new URLSearchParams("request=onlineboard-route-MOW-LED-20260515");
       const { container } = render(
diff --git a/src/features/online-board/components/OnlineBoardDetailsPage.tsx b/src/features/online-board/components/OnlineBoardDetailsPage.tsx
index 34a2d0d8..30706f44 100644
--- a/src/features/online-board/components/OnlineBoardDetailsPage.tsx
+++ b/src/features/online-board/components/OnlineBoardDetailsPage.tsx
@@ -21,7 +21,7 @@ import { useLiveFlightDetails } from "../hooks/useLiveFlightDetails.js";
 import { useOnlineBoard } from "../hooks/useOnlineBoard.js";
 import { parseDetailsRequestParam } from "@/shared/detailsRequestParam.js";
 import { buildFlightJsonLd } from "../json-ld.js";
-import { buildOnlineBoardUrl } from "../url.js";
+import { buildOnlineBoardUrl, parseFlightUrlParams } from "../url.js";
 import { getFlightSearchDate } from "../flightSearchDate.js";
 import { useCityName, useStationDisplayName } from "@/shared/hooks/useDictionaries.js";
 import { FlightDetailsAccordion } from "./details-panels/FlightDetailsAccordion.js";
@@ -65,6 +65,10 @@ export interface OnlineBoardDetailsPageProps {
   canonicalOrigin: string;
 }
 
+function parseParentFlightRequest(flightNumber: string, date: string): IParsedFlightId | null {
+  return parseFlightUrlParams(`${flightNumber}-${date}`);
+}
+
 /**
  * One side of a leg's station block — station code + airport name + city
  * + terminal, plus scheduled / expected / actual times formatted as
@@ -449,13 +453,14 @@ export const OnlineBoardDetailsPage: FC<OnlineBoardDetailsPageProps> = ({
     const backUrl = (() => {
       switch (parentRequest.kind) {
         case "flight": {
-          const m = parentRequest.flightNumber.match(/^([A-Z]{2,3})(\d+)$/);
-          if (!m || !m[1] || !m[2]) return `/${locale}/onlineboard`;
+          const parsed = parseParentFlightRequest(parentRequest.flightNumber, parentRequest.date);
+          if (!parsed) return `/${locale}/onlineboard`;
           return `/${locale}/${buildOnlineBoardUrl({
             type: "flight",
-            carrier: m[1],
-            flightNumber: m[2],
-            date: parentRequest.date,
+            carrier: parsed.carrier,
+            flightNumber: parsed.flightNumber,
+            ...(parsed.suffix ? { suffix: parsed.suffix } : {}),
+            date: parsed.date,
           })}`;
         }
         case "departure":
@@ -483,8 +488,10 @@ export const OnlineBoardDetailsPage: FC<OnlineBoardDetailsPageProps> = ({
       switch (parentRequest.kind) {
         case "flight": {
           // Angular renders "Рейс: SU 6188" — carrier and number space-separated
-          const m = parentRequest.flightNumber.match(/^([A-Z]{2,3})(\d+)$/);
-          const formatted = m?.[1] && m?.[2] ? `${m[1]} ${m[2]}` : parentRequest.flightNumber;
+          const parsed = parseParentFlightRequest(parentRequest.flightNumber, parentRequest.date);
+          const formatted = parsed
+            ? `${parsed.carrier} ${parsed.flightNumber}${parsed.suffix ?? ""}`
+            : parentRequest.flightNumber;
           return t("BREADCRUMBS.FLIGHT-NUMBER", { flightNumber: formatted });
         }
         case "departure":
@@ -594,7 +601,7 @@ export const OnlineBoardDetailsPage: FC<OnlineBoardDetailsPageProps> = ({
   }
 
   const legs = getLegs(displayFlight);
-  const flightNumber = `${displayFlight.flightId.carrier} ${displayFlight.flightId.flightNumber}`;
+  const flightNumber = `${displayFlight.flightId.carrier} ${displayFlight.flightId.flightNumber}${displayFlight.flightId.suffix ?? ""}`;
 
   const firstLeg = legs[0];
   const lastLeg = legs[legs.length - 1];
diff --git a/src/features/online-board/json-ld.test.ts b/src/features/online-board/json-ld.test.ts
index 96eb419d..afeb25a0 100644
--- a/src/features/online-board/json-ld.test.ts
+++ b/src/features/online-board/json-ld.test.ts
@@ -94,6 +94,14 @@ describe("buildFlightJsonLd", () => {
     expect(result.flightNumber).toBe("SU0100");
   });
 
+  it("TIRREDESIGN-13: includes suffix in flightNumber", () => {
+    const flight = makeDirectFlight({ carrier: "SU", flightNumber: "0038" });
+    flight.flightId.suffix = "D";
+    const result = buildFlightJsonLd(flight);
+
+    expect(result.flightNumber).toBe("SU0038D");
+  });
+
   it("maps departure airport", () => {
     const flight = makeDirectFlight({ depCode: "SVO", depAirport: "Sheremetyevo" });
     const result = buildFlightJsonLd(flight);
diff --git a/src/features/online-board/json-ld.ts b/src/features/online-board/json-ld.ts
index f3ebc3c2..1281ebcf 100644
--- a/src/features/online-board/json-ld.ts
+++ b/src/features/online-board/json-ld.ts
@@ -48,11 +48,11 @@ export function buildFlightJsonLd(flight: ISimpleFlight): Flight {
   const firstLeg = getFirstLeg(flight);
   const lastLeg = getLastLeg(flight);
 
-  const { carrier, flightNumber } = flight.flightId;
+  const { carrier, flightNumber, suffix } = flight.flightId;
 
   const result: Flight = {
     "@type": "Flight",
-    flightNumber: `${carrier}${flightNumber}`,
+    flightNumber: `${carrier}${flightNumber}${suffix ?? ""}`,
     provider: {
       "@type": "Airline",
       name: "Aeroflot",
diff --git a/src/ui/flights/FlightCard.test.tsx b/src/ui/flights/FlightCard.test.tsx
index 9a5572a8..4b7ad9b0 100644
--- a/src/ui/flights/FlightCard.test.tsx
+++ b/src/ui/flights/FlightCard.test.tsx
@@ -170,6 +170,15 @@ describe("4.1.13.3 Table 23 — Direct flight collapsed row", () => {
     expect(screen.getByTestId("flight-carrier-number").textContent).toContain("SU 0022");
   });
 
+  it("TIRREDESIGN-13: renders suffix in collapsed row flight number", () => {
+    const flight = {
+      ...makeFlight({}),
+      flightId: { carrier: "SU", flightNumber: "0038", suffix: "D", date: "20260514" },
+    } as ISimpleFlight;
+    render(<FlightCard flight={flight} expandable />);
+    expect(screen.getByTestId("flight-carrier-number").textContent).toContain("SU 0038D");
+  });
+
   it("T23-C2: renders operator logo (full, not mini/round) for direct flight", () => {
     render(<FlightCard flight={makeFlight({})} expandable />);
     const logo = screen.getByTestId("operator-logo");
diff --git a/src/ui/flights/FlightCard.tsx b/src/ui/flights/FlightCard.tsx
index 25e9c154..7f7d891d 100644
--- a/src/ui/flights/FlightCard.tsx
+++ b/src/ui/flights/FlightCard.tsx
@@ -184,7 +184,7 @@ export const FlightCard: FC<FlightCardProps> = ({
     ? childFlightIds
         .map((id) => `${id.carrier} ${id.flightNumber}${id.suffix ?? ""}`)
         .join(", ")
-    : `${flight.flightId.carrier} ${flight.flightId.flightNumber}`;
+    : `${flight.flightId.carrier} ${flight.flightId.flightNumber}${flight.flightId.suffix ?? ""}`;
   // TZ §4.1.22: when OperatingBy is null, resolve carrier from flight-number
   // ranges (SU1-2999→SU, SU5000-5399→DP, SU5400-5799→HZ, etc.).
   // Falls back to the flight's own carrier code for non-SU flights or when