# BOEING **Attachments** - AAVA BOEING 73x Checklist - Boeing 73x QRH (Quick Reference Handbook) **AAVA Checklist FCOM** # Cold Weather Operations - Boeing ### **AAVA – FLIGHT OPERATIONS MANUAL** ### **COLD WEATHER OPERATIONS – BOEING 737 SERIES (73x)** **FOR FLIGHT SIMULATION USE ONLY** --- #### **1.0 GENERAL** This section defines cold weather operational standards for all AAVA Boeing 737 series aircraft (including 737-700/800/900 variants). Procedures reflect Boeing FCOM/FCTM guidance and simulation-appropriate best practices. Cold weather operations apply when any of the following exist: – OAT/TAT at or below **10°C** – Visible moisture (rain, snow, ice crystals, fog) – Frost or ice present on aircraft surfaces – Operations from **contaminated taxiways or runways** The **Clean Aircraft Concept** applies at all times. --- #### **2.0 CLEAN AIRCRAFT CONCEPT** An aircraft **must not depart** unless all critical surfaces are free from contamination. The **Captain** is responsible for confirming the aircraft is clean after deicing/anti-icing and prior to takeoff. ##### **2.1 CRITICAL SURFACES** The following must be free of frost, ice, snow, or slush: – Wing leading edges, upper wing surfaces – Horizontal stabilizer, elevators – Vertical stabilizer, rudder – Slats, flaps, flap tracks – Engine inlets, spinner, fan blades – AoA vanes, pitot probes, static ports – Flight controls and fairings ##### **2.2 CLEAN AIRCRAFT VERIFICATION** A Clean Aircraft Check is required when: – Frozen precipitation continues after deicing – Holdover time is near expiration – A delay occurs after deicing – Fluid effectiveness is uncertain Verification may be completed from: – **Flight deck** (within HOT) – **Cabin overwing windows** (HOT expired or heavy precipitation) Left wing root is used as the reference point (first area sprayed, oldest fluid). --- #### **3.0 GROUND DEICING / ANTI-ICING** ##### **3.1 OVERVIEW** **Deicing** removes contamination. **Anti-icing** protects against further accumulation. Clear coordination between Flight Crew and Ground Deicing Personnel is required. ##### **3.2 APPROVED FLUID TYPES** ##### **Type I Fluid** – Hot glycol mixture – Used primarily for **deicing** – Short holdover time – Smooth glossy appearance indicates active protection ##### **Type IV Fluid** – Thickened, long-lasting anti-ice fluid – Applied after Type I – Provides extended protection before takeoff – Designed to shear off during takeoff roll ##### **3.3 HOLDOVER TIME (HOT)** Holdover Time begins when the **final anti-icing** application starts. HOT expires when the fluid can no longer prevent frozen contamination. Precipitation **anticipated** at application time affects HOT selection. ##### **3.4 ENGINE & AIRFRAME CONFIGURATION** ##### **Engines Running Deicing** – May be conducted only when the spray zone is safe – Crew and Ground Team must coordinate carefully – If APU is inoperative, crew may shut down the engine on the side being sprayed – Perform crossbleed start after completion ##### **Flaps During Deicing** The Boeing 737 uses **flap angles** (1°, 5°, 10°, 15°, 25°, 30°, 40°). – For uniform protection, extend flaps to **15°** prior to deicing when contamination on flap areas exists – If contamination is present on upper wing surfaces, extending to 15° does **not** risk damage – If flaps remain at 15° for flap-area contamination removal, do **not** retract until contamination is removed **CAUTION:** Retracting flaps below **15°** with contamination present can cause flap track damage. --- #### **4.0 IN-FLIGHT ICING OPERATIONS** ##### **4.1 WING ANTI-ICE OPERATION** Boeing WAI may be used in two ways: ##### **Primary Method — Deicer Mode** Activate WAI when ice is observed on: – Window frames – Wiper arms – Side window posts – Wing leading edges This method: – Produces clean leading edges – Minimizes runback ice – Reduces fuel and thrust penalties ##### **Secondary Method — Anti-Icer Mode** Use WAI **before** ice accumulation during prolonged exposure in **moderate or severe icing**. ##### **General Notes** – WAI is unnecessary below **–40°C SAT** – Turn WAI **OFF** when clear of icing – Avoid prolonged icing operation with flaps extended --- #### **5.0 ENGINE ANTI-ICE (EAI)** EAI must be used when: – OAT/TAT ≤ 10°C **and** visible moisture exists – Ice is detected or suspected – Conditions conducive to icing exist Indicators of engine icing: – Fan vibration – Increasing EGT at constant thrust – N1/N2 instability – Engine spool-up sluggishness Use **ENGINE ANTI-ICE switches ON** as required. --- #### **6.0 DESCENT IN ICING CONDITIONS** When descending or holding in **moderate or severe icing** with low thrust: Every ~15 minutes: – Increase thrust on **each engine separately** to a minimum of **70–80% N1** – Maintain increase for several seconds This sheds ice from: – Spinner – Fan blades – Inlet lips --- #### **7.0 APPROACH, LANDING & CONTAMINATED RUNWAY OPERATIONS** ##### **7.1 FLAP RETRACTION AFTER LANDING (BOEING 737)** If ice accumulation is present after landing: – Do **not** retract flaps **below 15°** – Maintain flaps at **15°** until ice is removed from: – Flap surfaces – Tracks – Fairings Once contamination is removed, flaps may be retracted to **UP**. ##### **7.2 REVERSE THRUST USE** On slippery or contaminated runways: – Use reverse thrust as required for a **safe stop** – Reduce reverse thrust smoothly below **60 kt**, depending on deceleration rate ##### **7.3 TAKEOFF FROM CONTAMINATED RUNWAYS** – Use **maximum takeoff thrust** – Within 5 minutes of takeoff: – Perform an **engine run-up to ~50% N1** for at least 5 seconds – Confirm stable engine operation – During a rejected takeoff, rudder provides primary directional control to approximately **60 kt** ##### **7.4 SAFETY PRIORITY** During landing or a rejected takeoff in contamination: **Stopping the aircraft is always the highest priority.**