SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B

FIGURE 1-6: MAINTENANCE ACCESS POINTS ...............................................................................................14 FIGURE 1-7: HYDRAULIC FLUID LEVEL PLACARD ........................................................................................16 FIGURE 1-8: FLUID TYPES AND QUANTITIES .................................................................................................16 FIGURE 1-9: JACK CRADLE RECOMMENDED MODIFICATION ....................................................................21 FIGURE 1-10: JACKING LOCATION ...................................................................................................................21 FIGURE 1-11: FLOAT SECURING LOCATIONS .................................................................................................22 FIGURE 1-12: FLOAT SECURING LOCATIONS OVERVIEW ...........................................................................23 FIGURE 3-1: NOSE WHEEL BOX ........................................................................................................................29 FIGURE 3-2: NOSE WHEEL GREASING ............................................................................................................30 FIGURE 3-3: NOSE GEAR & BOX ITEM .............................................................................................................32 FIGURE 4-1: MINIMUM BRAKE LINING THICKNESS .......................................................................................35 FIGURE 4-2A: MAIN GEAR, LOWER (OIL BATH WHEEL) ................................................................................37 FIGURE 4-2B: MAIN GEAR, LOWER (GREASED WHEEL) ..............................................................................37 FIGURE 4-3: MAIN GEAR GREASING POINTS .................................................................................................39 FIGURE 4-4A: MAIN GEAR ADJ. DOWN ............................................................................................................40 FIGURE 4-4B: MAIN GEAR ADJ. DOWN ............................................................................................................41 FIGURE 4-5: MAIN GEAR ADJ. UP......................................................................................................................42 FIGURE 4-6: MAIN GEAR DOWN STOP ADJ. ....................................................................................................43 FIGURE 4-7: ROTARY ACTUATOR .....................................................................................................................48 FIGURE 4-8: MAIN SHOCK STRUT ....................................................................................................................49 FIGURE 5-1: HYDRAULIC SCHEMATIC .............................................................................................................54 FIGURE 6-2: WATER RUDDER/STEERING CABLE ROUTING, MODEL 208 .................................................59 FIGURE 6-3: WATER RUDDER/STEERING CABLE ROUTING, MODEL 208B ..............................................59 SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 6 Revision R P/N 1005723 Doc. No. W8750-24-01 WIPLINE FLOATS • SKIS • MODIFICATIONS • AIRCRAFT SALES AVIONICS • INTERIOR • MAINTENANCE • PAINT REFINISHING NEW CUSTOMER INFORMATION Customer Name Billing Address Shipping Address Phone Number Fax Number Purchasing Contract Phone Number Email Fax Number Accounts Payable Contact Phone Number Email Fax Number Type(s) of Aircraft Owned or Maintained Model(s) of Floats and Skis Owned or Maintained FedEx and/or UPS Account Number (if applicable) Please return to Wipaire Customer Service: Fax (651) 306-0666 Phone (651) 306-0459 Email: CustomerService @wipaire.com SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 7 CHAPTER 1 INTRODUCTION AND GENERAL INFORMATION CONTENTS 1.0 INTRODUCTION ...............................................................................................................................................8 1.1 GENERAL FLOAT INFORMATION ................................................................................................................15 1.2 CLEANING .......................................................................................................................................................18 1.3 CORROSION ...................................................................................................................................................19 1.4 TOWING ...........................................................................................................................................................20 1.5 HOISTING ........................................................................................................................................................20 1.6 LEVELING ........................................................................................................................................................20 1.7 JACKING PROCEDURES ..............................................................................................................................20 1.8 JACK REMOVAL ..............................................................................................................................................23 1.9 MOORING ........................................................................................................................................................23 SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 8 Revision R P/N 1005723 Doc. No. W8750-24-01 CHAPTER 1 INTRODUCTION AND GENERAL INFORMATION This manual is provided for the owners of Wipaire model 8750 Floats as installed on the Cessna 208 Caravan and 208B Grand Caravan. It has two main priorities: To inform owners of the level and amount of servicing required to properly maintain their floatplane, and to provide technical data and servicing as specified to maintenance professionals charged with servicing the floats. The service products referred to throughout this manual are described by their trade names and may be purchased from the Wipaire Parts Department. When performing standard repairs for Wipline Aluminum Floats, please refer to the “Structural Repair Manual For Wipline Aluminum Floats” part number 1008274. It is available free of charge online at www.wipaire.com. Reference Wipaire document number 1011959 for STC SA1311GL for a list of commercial parts. We, at Wipaire, welcome your purchase and look forward to years of satisfying exchanges with you. Your floats are built with pride and attention to detail, but we want that care to extend beyond your purchase. Our customer service department is available for your questions 24 hours a day, 7 days a week, where ever you are in the world. Parts Sales and Technical Support Dept: Wipaire, Inc. 1700 Henry Avenue – Fleming Field South St. Paul, MN 55075 Telephone: (651) 306-0459 Fax: (651) 306-0666 Website: www.wipaire.com Email: CustomerService@wipaire.com In this service manual we have worked hard to include many repair scenarios in addition to the recommended products, practices, and routine maintenance required to keep your floats in working order. When a float part is significantly changed, or an additional inspection is recommended or required, often a service letter and/or kit is issued. If a warranty is issued, most commonly it is for an 18-month time period, so it is crucial to check for service letters specific to your float model at each periodic inspection to be eligible. Service Manuals and the installation prints included are also revised periodically and kept updated. Service letters, Service Kits and Service Manuals are available on our web site at no charge, www.wipaire.com. NOTE: IT IS CRITICAL TO CHECK FOR MANUAL UPDATES EACH TIME AN INSPECTION IS EXECUTED. 1.0 INTRODUCTION SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 9 FIGURE 1-1: FRONT VIEW CESSNA 208 CARAVAN SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 10 Revision R P/N 1005723 Doc. No. W8750-24-01 FIGURE 1-2: TOP & SIDE VIEWS CESSNA 208 CARAVAN SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 11 FIGURE 1-3: FRONT VIEW CESSNA 208B CARAVAN SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 12 Revision R P/N 1005723 Doc. No. W8750-24-01 FIGURE 1-4: TOP & SIDE VIEWS CESSNA 208B CARAVAN SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 13 FIGURE 1-5: FLOAT TERMINOLOGY SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 14 Revision R P/N 1005723 Doc. No. W8750-24-01 FIGURE 1-6: MAINTENANCE ACCESS POINTS SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 15 1.1 GENERAL FLOAT INFORMATION The model 8750 amphibious float is an all aluminum structure. The alloy used throughout is mostly corrosion resistant 6061-T6, with 2024-T3 and 7075-T651 used in strength critical fittings and panels. Interior parts are cleaned, acid-etched and then primed prior to being riveted for enhanced corrosion resistance. Exterior surfaces are cleaned, alodine is applied as a corrosion resistant barrier, and then primed and custom painted. Model 8750 floats contain sixteen (16) water tight compartments per hull. Access to the inside of the floats for cleaning, inspection and repairs is through the access covers on the float deck and the access covers inside the wheel well. Figures 1-1 and 1-2 show three view drawings of the Cessna 208 as installed on Wipline model 8750 amphibious floats. Figures 1-3 and 1-4 show three view drawings of the Cessna 208B as installed on Wipline model 8750 amphibious floats. As a part of the float installation, the following additional changes are made to the landplane: 1. The hydraulic landing gear retraction system components and cockpit controls are added 2. The landing gear emergency gear operation hand pump and system are added 3. A water rudder steering system is installed 4. Auxiliary Vertical Fins (Finlets) are added 5. A seaplane extended chord rudder is installed 6. TKS pod & reservoir (if equipped) is removed Operational information is detailed in the Cessna 208 Airplane Flight Manual Supplement or Cessna 208B Airplane Flight Manual Supplement. Actual displacement for each float in fresh water is: Amphibian: at 100% Buoyancy = 8240 pounds at 80% Reserve = 9155 pounds Seaplane: at 100% Buoyancy = 8741 pounds at 80% Reserve = 9712 pounds LANDING GEAR The landing gear incorporated within the amphibious floats is a retractable quadricycle type with two swiveling nose (or bow) wheels and four (4) (two (2) dual sets) of main wheels. Shock absorption is provided by air-oil shock struts on the two main landing gear assemblies and composite flat springs on the nose gear assemblies. Each main wheel is equipped with a hydraulically-actuated disc brake. Landing gear extension and retraction is accomplished by two (2) electrically-driven hydraulic pumps and four (4) hydraulic actuators (one (1) for each gear). The hydraulic pumps are located in the aircraft empennage and can be accessed by removing the aft cabin bulkhead. The hydraulic actuators are located adjacent to each gear. Hydraulic system fluid level should be checked at 25-hour intervals and should be serviced to levels in SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 16 Revision R P/N 1005723 Doc. No. W8750-24-01 The nose wheels are fully castoring for maneuverability while the airplane is under engine power or being towed. The main landing gear has dual 6:00x6 8-ply tires and the nose gear has a single 5:00x5 10-ply tire. All tires must be approved to TSO C62, type III. Differential use of the main-wheel brakes steers the aircraft on land. Grease zerks are provided in many locations that have pivoting joints. Greasing is recommended at 25-hour intervals, or more often depending on operating environment, with HCF Grease or equivalent. See Figure 3-2 for nose gear grease zerk locations. See Figure 4-3 for main gear grease zerk locations. OLEO STRUT & TIRE SERVICING Full service of the oleo strut is accomplished by releasing the nitrogen pressure, draining the hydraulic fluid, refilling the hydraulic fluid to level in Figure 1-8, and servicing with nitrogen to pressure specified in Figure 1-8. FIGURE 1-7: HYDRAULIC FLUID LEVEL PLACARD FIGURE 1-8: FLUID TYPES AND QUANTITIES accordance with the installed placard using MIL-H-5606 (red) hydraulic fluid. The fluid level placard (Figure 1-7) is installed on the forward hydraulic Reservoir. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 17 STRUT PACKAGE The strut package attaches the floats to the aircraft. The strut package is comprised of the forward struts, main pylons, rear cross-wires, and front cross wires (or flying wires). The streamlined struts are made from extruded aluminum alloys. The main pylon is built from machined aluminum trusses, internal ribs, and skinned with aluminum sheet. WATER RUDDERS The floats are equipped with water rudders attached at the rear of the float structure. These rudders steer when the floats are in the water. Rudder controls are integrated into the existing aircraft rudder system and should move in the same direction as the air rudder. Water rudders are extended and retracted with a handle installed to the right of the pilot seat. Water Rudder & Springs SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 18 Revision R P/N 1005723 Doc. No. W8750-24-01 The outside of the float should be kept clean by washing with fresh water and soap. Special care should be taken to remove engine exhaust trails, water-line marks, and barnacle deposits. After salt water operations, washing with fresh water should be done daily with special attention paid to hard to reach places like: - skin seams - wheel well areas - float attach points - hardware Alternatively, water taxiing in fresh water at step-speed can help flush the floats themselves, but additional rinsing should be conducted on struts and fittings. The float interior should be flushed out, especially if salt water or polluted water gets inside the compartments. If the floats are being stored inside a building either installed on the aircraft or not, it is strongly recommended to remove the inspection covers so the interior of the floats can dry out. 1.2 CLEANING OPERATORS IN SALT WATER ARE STRONGLY CAUTIONED RINSING THE AIRCRAFT AND FLOATS WITH FRESH WATER AT THE END OF EACH DAY IS CRITICAL. ADHERING TO THESE CLEANING RECOMMENDATIONS IS VITAL FOR KEEPING CORROSION TO A MINIMUM. FAILURE TO CLEAN THOROUGHLY CAN SEVERLY SHORTEN THE LIFE OF THE FLOATS. SALT WATER, POLLUTED WATER AND THEIR ENVIROMENTS, ARE STRONGLY AND DIRECTLY LINKED TO CORROSION AND MUST BE HANDLED PRO ACTIVELY. EVEN WITHOUT DIRECT CONTACT WITH SALTWATER, THIS HYDRAULIC PUMP IN THE AIRCRAFT FUSELAGE HAS SEVERELY CORRODED DUE TO BEING IN A SALTWATER ENVIRONMENT WITHOUT BEING KEPT CLEAN. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 19 CORROSION HOT SPOTS - DISSIMILAR METAL CONTACT LIKE LANDING GEAR, FLOAT ATTACH POINTS AND OTHERS. - ENCLOSED SPACES THAT STAY MOIST LIKE LANDING GEAR FLOAT INTERIORS, SKIN LAP-JOINTS, AND OTHERS. - CONTAMINATES ON THE METAL LIKE DIRT, SALT, ENGINE EXHAUST, AND OLD OR OTHERWISE COMPRISED GREASE. Corrosion is the process by which metals are turned into oxides. It is a natural and ultimately unavoidable chemical reaction that is accelerated by dissimilar metals in contact with each other, and enclosed spaces and contaminants like dirt and exhaust deposits that hold moisture against the metal. If that moisture is salt water or fresh water that is polluted, it conducts the electrolytes better and the process of corroding is faster. Most aircraft and most floats are made out of aluminum due to its strength to weight ratio, and its ability to withstand fatigue and remain field repairable. Steel is used for strength in hardware and landing gear parts, and these are often areas where these dissimilar metals cause corrosion. Areas where moisture and dirt mix and stay wet against metal are common sites of oxidation. Float strut attach points, water rudders, and skin joints are examples of areas where this occurs. Cladding, plating, anodizing, painting, greasing and waxing are all processes used to help protect metal from corrosion; Wipaire uses all these techniques during manufacture. But due to the rugged way our floats are used and the environment, these surface sealers become abraded or wear away, leaving the metal exposed. Removal of corrosion is detailed more fully in Chapter 9, but there are a few things an owner can do to stop the spread of corrosion and minimize the damage. Aside from the already detailed cleaning and inspection procedures, an anti-corrosion spray like Corrosion X, or its equivalent, should be used liberally. Because it has the ability to displace moisture and contaminants, it can be used when the floats are still wet or when they are dry. 1.3 CORROSION SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 20 Revision R P/N 1005723 Doc. No. W8750-24-01 Periodically, hardware should be covered with waterproof grease. Especially in a salt water environment, bolts should be removed at least once a year and grease applied to the shafts, bolt/screw heads, and nuts. 1.4 TOWING When towing the amphibian aircraft, 2 lugs are provided on the lower forward side of the nose spring. On land, a rigid “V” frame can be fabricated to attach to these lugs for towing the aircraft with a tractor. Lake & Air Training and Pilot Shop has this tow bar available for purchase. On water, a rope bridle arrangement can used to tow the aircraft from the lugs described above. 1.5 HOISTING Hoisting the aircraft can be performed using a lifting rig that attaches to the aircraft with lifting rings that are installed at the wing attach points. If the lifting rings are not installed, reference applicable aircraft maintenance/ service manual for additional hoisting specifications. Lake & Air Training and Pilot Shop has this hoisting rig available for purchase. Contact Wipaire Customer Service for additional guidance in removal or installation of floats. CAUTION! Make sure nothing is under or above the airplane or floats when hoisting the aircraft 1. Raise aircraft high enough to place float cradle under floats as shown in Figure 1-12. 2. Lower aircraft onto float cradle as shown in Figure 1-12. 3. Place fore and aft supports as shown in Figure 1-11 and Figure 1-12. 1.6 LEVELING See applicable aircraft maintenance/service manual. 1.7 JACKING PROCEDURES CAUTION! Make sure nothing is under or above the airplane or floats when jacking the aircraft. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 21 1. Turn off fuel. 2. Place weighted bags above the nose gear (approximately 100 lbs. on each float to start, more may be added as needed). 3. Position 1 person at each fore and aft of each float, and 3 people at the jacking location of one float. 4. Modify jack saddle of a 3 ton minimum jack by welding as shown in Figure 1-9. (X = WIDTH OF CRADLE) FIGURE 1-9: JACK CRADLE RECOMMENDED MODIFICATION NOTE: This is not required and Wipaire does not have the parts for modification. It is recommended a similar modification be performed to the jack saddle to prevent the slippage of the cradle. 1. Center cradle on saddle and position so cradle is as far aft on the main keel as possible without interfering with main gear as it decompresses as shown in Figure 1-10. NOTE: If desired to prevent possible cosmetic damage to float, use material to separate cradle and float. FIGURE 1-10: JACKING LOCATION 1. Jack one side at a time, taking care to check the balance of the aircraft and adding more weight to the front if needed. 2. Two people, both outboard, lift the fore and aft cradle stands up to the cradle as a 3rd person release the pressure slowly, allowing the cradle and stands to gently contact the ground. 3. Repeat previous procedure to the other float. NOTE: A smaller jack may be needed to slightly lift the float into a high enough position for the main jack. 4. Secure floats with fore and aft supports as shown in Figure 1-11 and Figure 1-12. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 22 Revision R P/N 1005723 Doc. No. W8750-24-01 FIGURE 1-11: FLOAT SECURING LOCATIONS ALTERNATE JACKING METHOD IF WIPAIRE JACKING FIXTURE IS NOT AVAILABLE (8000A model shown for reference only) SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 23 Aft Cradle Stand Fore Cradle Stand Cradle Fore Support Aft Support (8000A MODEL SHOWN FOR REFERENCE ONLY) FIGURE 1-12: FLOAT SECURING LOCATIONS OVERVIEW 1.8 JACK REMOVAL Make sure nothing is under or above the airplane or floats when removing the jacks from the aircraft 1. Turn off fuel. 2. Verify landing gear is in the down and locked position. 3. Verify weighted bags are still located above the nose gear. 4. Position 1 person at each fore and aft of each float, and 1 person at the jacking location of one float. 5. Remove all fore and aft supports as shown in Figure 1-11 and Figure 1-12. 6. Using modified jack saddle as shown in Figure 1-9, center jack saddle in center of cradle on 1 of the floats, 7. Lift aircraft to clear fore and aft cradle stands and remove fore and aft cradle stands of lifted float. 8. Slowly lower float to the ground, remove jack from under float, and remove cradle from jack saddle. 9. Repeat previous procedure to the other float. 10. Remove weighted bags from floats. 1.9 MOORING For land operations, the aircraft is equipped with three fixed mooring points. Two are located on the outboard edge of the wing struts and the other is located on the underside of the tail section of the aircraft. Mooring Procedure on Land: 1. Position the aircraft near mooring location and it point into the wind. 2. Set the parking brake and/or chock the main wheels. 3. Install the aircraft control column lock. 4. Install the flight control gust lock. 5. Tie down the aircraft to anchor points on the ground. 6. Install provided engine inlet covers, pitot tube covers, and propeller anchor assembly. 7. Attach a static ground cable to one of the aircraft tie-down eyelets and the ground anchor point. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 24 Revision R P/N 1005723 Doc. No. W8750-24-01 For water operations, the floats are equipped with two deck cleats on each float, one forward near the pilot/copilot doors, and one aft near the cargo door. Mooring Procedure on Water at Dock: 1. Position the aircraft near the dock and point into the wind as much as able. 2. Install the control column lock. 3. Install the flight control gust lock. 4. Tie down using both deck cleats to secure aircraft to dock and keep it from moving if wind direction shifts. Mooring Procedure on Water at Buoy: 1. Position the aircraft near buoy. 2. Install the control column lock. 3. Install the flight control gust lock. 4. Tie to buoy using one deck cleat and leave sufficient slack in the rope so that the aircraft can move as the wind direction shifts without causing damage to aircraft. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 25 CHAPTER 2 AIRWORTHINESS LIMITATIONS CONTENTS 2.0 AIRCRAFT AIRWORTHINESS ......................................................................................................................26 SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 26 Revision R P/N 1005723 Doc. No. W8750-24-01 2.0 AIRCRAFT AIRWORTHINESS SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 27 CHAPTER 3 NOSE GEAR CONTENTS 3.0 NOSE GEAR ....................................................................................................................................................28 3.1 ADJUSTMENT/TEST NOSE GEAR ...............................................................................................................30 3.2 NOSE GEAR BASIC SERVICING ..................................................................................................................30 3.3 NOSE GEAR DISASSEMBLY .........................................................................................................................31 3.4 NOSE GEAR ASSEMBLY ...............................................................................................................................31 SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 28 Revision R P/N 1005723 Doc. No. W8750-24-01 3.0 NOSE GEAR The nose gear consists of composite fiberglass beams that are attached on top to a moving carriage and on the bottom to blocks that caster. Inside the block is a castoring pin that is set into the machined fork assembly; the castoring pin allows the nose wheel to pivot 360 degrees. Geometry is such that no shimmy dampers are necessary. The nose gear has an over-center down lock. Retraction occurs when pressure is applied to the forward face of the actuator piston and the carriage is drawn along the tracks in the nose box. Gear position light proximity switches are closed when the piston (containing magnetic material) has reached either end of its travel. Refer to Figure 3.1 for visual reference The nose gear has single 5:00 x 5 10-ply tire. All tires must be approved to TSO C62, type III. NOSE WHEEL AND TIRE REMOVAL To remove each nose wheel: 1. Jack the aircraft, completely lifting both hulls. It is not recommended to jack only one hull. 2. Cut cotter pin and remove axle nut. 3. Remove the AN4 bolt securing the opposite side of the axle. 4. Pull/Push the axle through the side plate. (either direction) taking care to set spacers aside as they are removed. 5. Wheel will drop out between side plates once axle has been removed a sufficient distance. Each nose wheel is a split-type rim. To remove the tire: 1. Remove air from tire. 2. Remove six (6) bolts that hold the wheel together. 3. Split rim and remove tire and tube. Nose tires should be replaced when the tread is worn through in any area. Reinstallation is the reverse of removal. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 29 FIGURE 3-1: NOSE WHEEL BOX SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 30 Revision R P/N 1005723 Doc. No. W8750-24-01 3.1 ADJUSTMENT/TEST NOSE GEAR Refer to Figure 3.1 for visual reference. Adjustment of actuator stroke is provided at the ends of the piston rods. The length of the nose gear rod is adjusted such that the over-center knuckle (brass) rollers just bottom out on the down side and the piston just bottoms out on the mounting flange. The up stops nests in the up-stop pins. Nose gear proximity switches are located on clips that are mounted on the outer cylinder body, one on each end. The most forward switch is for the gear down lights and most aft is for the gear up position lights. Set the proximity switch mounting clip along outer cylinder body to a position such that the light goes out when the over-center track is about ¼ inch from bottomed position while traveling in the up direction. Lights should come on about 1/8 inch from the bottomed position while traveling in the down direction. The cylinder piston has a magnet that will activate the proximity switches. 3.2 NOSE GEAR BASIC SERVICING Refer to Figure 3-2 for visual reference. The nose gear pivot assembly should be cleaned and inspected every 25 hours or more frequently whenever in water for an extended period of time, especially saltwater. Tracks and blocks should be cleaned and left dry or alternately cleaned and wiped with a rag with dry silicone spray on it. The nose wheels contain grease nipples for the wheel bearings. They should be greased every 25 hours. Nose tires are standard 5:00 x 5, 10-ply, inflated to 60 +/- 5 psi. All tires must be approved to TSO C62, type III. FIGURE 3-2: NOSE WHEEL GREASING SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 31 3.3 NOSE GEAR DISASSEMBLY (In float or removed from float) Items refer to areas on Figure 3-3. 1. Disconnect hydraulic lines. Item 1 2. Remove the 4, NAS1103-2 bolts and washers attaching the Nose Ram, Item 2, to the flange assembly, Item 3, and slide the Nose Ram off of the flange assembly. 3. Inspect interior bore of the Nose Ram for corrosion and pitting. 4. Loosen AN316-10R Jam Nut, Item 4, on Nose Ram Rod End, Item 5. 5. Using a strap wrench or other suitable, non-marring tool, unthread the Ram, Item 6, from the Nose Ram Rod End. Do not attempt to remove the ram piston top (brass) from the ram shaft (stainless steel). They are assembled as a unit and permanently secured. 6. Remove Ram Assembly, Item 3, if desired to replace the T-seals, Item 10, felt wiper, Item 7, and plastic wiper, Item 8. 7. Replace T-seals on the Nose Ram, Item 9, and Ram Assembly, Item 3, if necessary. The T-Seal in the Cylinder End-Cap, Item 11, can be replaced by removing the NAS1103-2 bolts and removing the cap from the Cylinder. 8. Slide the Trolley, Item 12, out bottom of nose gear track. 9. If worn or damaged, replace the 4 Slide Blocks, Item 13, and the 2 Track Rollers, Item 14. Note: Slide Block, Item 13, notches should face toward each other. 10. Grease the 2 axles, Items 15 & 16, when reassembling. 3.4 NOSE GEAR ASSEMBLY Items refer to areas on Figure 3-3 1. Insert the Ram Assembly, Item 6, into the Flange Assembly, Item 3, if removed during disassembly. 2. Slide the Trolley, Item 12, with installed blocks and rollers into nose box track from bottom. 3. Pull forward on the Link, still attached to the Rod End, Item 5, to place the rollers, Item 14, into the down lock pocket on the nose box track. 4. Thread the Ram Assembly, Item 6, onto the Rod End, Item 5, until the ram piston contacts the Flange Assembly, Item 7, while at the same time the rollers are seated in the down lock pocket. Both the piston and the rollers need to bottom out against their respective mating parts at the same time. 5. Tighten the AN316-10R jam nut against the rod end. 6. Install the Nose Ram, Item 2, onto the Flange Assembly, Item 3, being careful not to nick T-Seals on bolt holes. Fasten with NAS1103-2 bolts and necessary washers. 7. Oil felt wiper through oil cup on the Flange assembly, Item 3. 8. Connect hydraulic lines to cylinder and cycle gear to fill cylinder with fluid. 9. Service hydraulic system with Mil-H-5606 if necessary. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 32 Revision R P/N 1005723 Doc. No. W8750-24-01 FIGURE 3-3: NOSE GEAR & BOX ITEM SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 33 CHAPTER 4 MAIN LANDING GEAR BRAKES & GEAR RETRACTION CONTENTS 4.0 GENERAL.........................................................................................................................................................34 4.1 MAIN GEAR RETRACTION DESCRIPTION .................................................................................................38 4.2 MAIN GEAR ASSEMBLY SETUP AND ADJUSTMENT ................................................................................44 4.3 ADJUSTING THE GEAR UP POSITION ........................................................................................................47 4.4 ADJUST MAIN UP AND DOWN POSITION SWITCHES .............................................................................47 4.5 EMERGENCY GEAR OPERATION ...............................................................................................................50 SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 34 Revision R P/N 1005723 Doc. No. W8750-24-01 4.0 GENERAL The main landing gear incorporated within the amphibious floats are retractable, quadricycle type with four main wheels in a dual tire formation. Air-oil shock struts on the two main landing gear assemblies provide shock absorption. The main landing gear has dual 6:00 x 6 8-ply tires. All tires must be approved to TSO C62, type III. The gear system is hydraulically actuated and driven by two hydraulic pumps. Brakes are hydraulic and there is a caliper on each main wheel. INTRODUCTION OF OIL BATH WHEELS Prior to float serial number 87223 (pre Service Letter 171), main wheels are greased via main axle zerks. Float serial numbers 87223 and later (and earlier serial numbers that have had Service Letter 171 accomplished) have oil bath lubricated main wheels. BRAKE REMOVAL & INSPECTION Each main wheel has a dedicated brake caliper. To remove the brake caliper: 1. Remove two mounting bolts on each caliper. 2. Compress the caliper piston using a c-clamp. 3. Slide caliper off of the brake disc. 4. At brake installation, apply STA-Lube synthetic brake and caliper grease or equivalent to brake caliper pins. Brake pads should be replaced when the minimum section thickness is less than 0.100”, see Figure 4-1. Generally, the brake discs should be checked for wear, grooves, deep scratches, and excessive pitting. Pitting deeper than 0.015” or thickness below 0.327” is cause for replacement. MAIN WHEEL AND TIRE REMOVAL AND INSPECTION To remove each main wheel: 1. Remove brake caliper. 2. For oil bath wheels: a. Drain oil from the axle by removing the plug in the hub cap of the inboard wheel. b. After oil drains, remove snap ring and hub cap. 3. Cut cotter pin and remove axle nut. 4. Pull wheel off of axle. Each main wheel is a split-type rim. To remove the tire: 1. Remove air from tire 2. Remove 3 bolts that hold wheel together 3. Split rim and remove tire and tube Main gear tires should be replaced when the tread is worn through in any area. Reinstallation is the reverse of removal for tires, wheels, and brakes. FOR OIL BATH WHEELS Inspect an oil sample taken from the axle. Look for signs of bearing wear including metal shavings or other impediments in the oil. If the oil sample is clean and there are no abnormalities with the wheel spinning, further SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 35 FIGURE 4-1: minimum brake lining thickness MAIN GEAR/WHEEL ALIGNMENT There is no way to adjust the alignment within each main gear wheel set. If the tires are showing signs of abnormal/asymmetric wear, some component has likely been worn/bent. Starting with the axle, examine each main gear component and mounting point for signs of damage/deformation. Replace damaged components once found. If no gear/bulkhead/airframe components are found to be damaged, use the following procedure to align left and right floats: 1. Move aircraft to level surface, ensure both nose wheels are facing aft (i.e. positioned for forward motion). 2. Measure the length of the forward flying wires, from the aft face of the clevis on each end. These distances should be equal. If they are not, loosen the jamb nuts and adjust the wires as required so the length of each is equal. 3. Tighten each forward wire until is snug, then tighten the jamb nuts. Wire should not be overly tight but should be tight enough to prevent excessive motion at the center. 4. Next, tighten the aft wires in a similar fashion; measuring between the face of the clevises and loosening, then tightening the wires until they are of equal. Secure with jamb nuts. inspection including removing the wheel only needs to be done at the inspector’s discretion. Note: Some grease may show up in the oil sample as a result from grease used by the wheel manufacturer. Grease does not affect the wheel bearing lubrication, but oil may be changed to flush loose grease from the system if desired. Main gear tires should be replaced when the tread is worn through in any area. Reinstallation is the reverse of removal for tires, wheels, and brakes. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 36 Revision R P/N 1005723 Doc. No. W8750-24-01 BLEEDING BRAKE SYSTEM Whenever the hydraulic brake lines are disconnected and reattached the brake system should be bled. To bleed the brake system: 1. Check that all lines are properly attached between the brake calipers and brake master cylinders. 2. Check brake fluid reservoir level and fill to MAX line (located on the pilot side of the engine compartment mounted to the firewall). 3. Depress brakes using pilot pedals, brakes will likely be “spongy” and need significant travel to build braking force. 4. Loosen hydraulic fitting at one brake caliper just enough to let fluid and air seep out when brakes are actuated. 5. While one person actuates the brakes, a second person should watch the brake caliper with the loose fitting. 6. If air is in the system, actuating the brakes will cause bubbles in the fluid coming out of the loosened brake caliper fitting. 7. Actuate the brakes through full travel several times until all the bubbles have been released and fluid is being expelled at the loose caliper without signs of air. 8. Tighten the loose caliper fitting. 9. Check fluid level in brake fluid reservoir and refill to MAX line as necessary. 10. Repeat procedure at each caliper. 11. When complete, brakes should not feel “soft” or “spongy” when actuated. BLEEDING BRAKE SYSTEM (ALTERNATE METHOD) When the Hydraulic Brake system is disconnected use the primary procedures listed in the previous section, or as an alternative method to bleed the brake system is cross bleeding between main gear calipers and to brake reservoir (Back Bleeding). To bleed the brakes system using this alternate method: 1. Connect pressurize brake bleeding system to outboard caliper. CAUTION WHEN PERFORMING CROSS BLEEDING, IT MAY BE NECESSARY TO REMOVE RESIDUAL FLUID FROM BRAKE RESEVERIOR TO PREVENT OVERFLOW. 2. Open inboard and outboard bleeders on main gear and pump fluid between calipers till all air has been purged from calipers. 3. Tighten inboard caliper bleeder and continue pressurization to reservoir till all air has been purged from line. 4. Perform steps 1 thru 3 on opposite main gear. 5. When complete check brake fluid in reservoir service to max line if necessary. 6. When complete, brakes should not feel “soft” or “spongy” when actuated. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 37 FIGURE 4-2A: MAIN GEAR, LOWER (OIL BATH WHEEL) FIGURE 4-2B: MAIN GEAR, LOWER (GREASED WHEEL) SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 38 Revision R P/N 1005723 Doc. No. W8750-24-01 4.1 MAIN GEAR RETRACTION DESCRIPTION Refer to Figures 4-1, 4-2A, 4-2B, 4-3, 4-4A, 4-4B, 4-5 and 4-6 for visual reference. Retraction and extension of the main gear is accomplished with a hydraulic rack and pinion type actuator. The actuator consists of two opposing pistons connected by a geared rack, with a rotating pinion gear in the middle. Hydraulic fluid is transferred from one piston to the other using an electrically reversible hydraulic pump located in the empennage of the aircraft. The differential pressure builds up causes the piston to move, pushing the rack and rotating the pinion gear and its attached drive shaft. Attached to each end of the drive shaft are actuating arms that drive separate rod linkages with adjustable rod ends. The drive shaft and actuating arms have a keyway to prevent slippage on the rotating drive shaft. The rod linkages push and pull on the Main Gear Top Arm Assembly causing it to pivot around a fixed point. Also attached to the actuators drive shaft is a visual gear position indicator. This indicator consists of colored bands that rotate with the drive shaft allowing the pilot to visually determine the position of the main landing gear by looking at a placard on the deck of the float. Since the actuator rotates through approximately 193 degrees, the rod linkages and the actuating arm pass an over center point, preventing reverse driving of the rack and pinion actuator in both the fully extended and fully retracted positions. The actuator rotation is adjusted by setscrews that determine the length of travel of the actuator pistons. Providing an over center up-lock prevents inadvertent main gear extension in the case of a hydraulic failure. As a secondary safety to ensure the geometry remains over center with a hydraulic failure, a spring is installed on the actuating arm preventing motion of the rack and pinion actuator. Since the retraction mechanism is over center, the weight of the landing gear and oleo, when retracted, also prevent the retraction mechanism from rotating past the over center point. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Doc. No. W8750-24-01 P/N 1005723 Revision R Page 39 FIGURE 4-3: MAIN GEAR GREASING POINTS In addition to the over center locking provided by the rod linkages and actuator arm for the gear extended position, a second down locking method is provided as well. The geometry of the main gear drag link, oleo- pneumatic shock strut and the top arm assembly, provide an additional over center locking method. The force vector from the oleo, (directed in line with the centerline of the oleo assembly) rotates the contacting face on the top arm assembly into contact with the main gear top mount at all positions of oleo stroke. This transfers the landing load into a structure designed to withstand the generated landing forces, as well as prevents the top arm from rotating and collapsing the main landing gear. There are two proximity switches on each main gear unit. One for sensing gear up position, and the other for gear down position. These are easily replaceable and can essentially be adjusted during maintenance, see figure 4-4A and 4-5. The proximity sensors have a built in LED to indicate when they are sensing the gear position. This feature greatly aids in the setup and servicing of the sensors. There are several service points on the main landing gear to pay attention to during maintenance. Grease zerks are located on the pivots of the main gear draglinks, each wheel axle, top and bottom pivot points on the oleo- pneumatic shock strut, and the rotation point of the top arm assembly, see figure 4-3. The adjustable rod end bearings are permanently sealed and do not require servicing. Inspect the rod ends for freedom of movement and corrosion. Replace the rod ends when necessary. Depending on the operating environment, greasing requirements may vary. Highly corrosive environments, such as salt water, may require more frequent inspections. Regardless, the gear should be inspected visually at least every 25 hours for cleanliness and proper lubrication. Note: If replacing any of the (4) bushings located within the pivot arm which are serviced by the trunion zerks (see Figure 4-3), the internal grooves must be aligned to the zerk fitting and a grease hole must be drilled into the bushing after insertion. SERVICE MANUAL & ICA 8750 AMPHIBIAN/SEAPLANE FLOATS ON CESSNA 208/208B Page 40 Revision R P/N 1005723 Doc. No. W8750-24-01 FIGURE 4-4A: MAIN GEAR ADJ. DOWN