helicopter structure

FOR TRAINING PURPOSE ONLY Malaysian Institute of Aviation Technology

WEEK 3:

HELICOPTER STRUCTURE (CONTINUE)

04/11/23 SABRI OMAR 1


LEARNING OBJECTIVES AND OUTCOMES

OBJECTIVES:

1. GAIN KNOWLEDGE ON METHOD OF CONSTRUCTION AND ATTACHMENT OF FIREWALL.

2. GAIN KNOWLEDGE ON VARIOUS TYPE OF HELICOPTER LANDING GEAR SYSTEM.

OUTCOMES:

1. DESCRIBE THE FUNCTION AND PURPOSE OF FIREWALL AND HOW IT IS CONTRUCTED AND ATTACHED TO HELICOPTER.

2. DESCRIBE THE VARIOUS TYPE OF LANDING GEAR INSTALLATION.

04/11/23 Copyright Allen Peter Diman 2


INTRODUCTIONINTRODUCTION

FIREWALL

1. IN THIS LESSON WE SHALL LOOK AT THE FOLLOWINGS;

– FUNCTION OF FIREWALL

– CONSTRUCTION OF FIREWALLS

– INSTALLATION OF FIREWALLS

– MAINTENANCE OF FIREWALLS

LANDING GEAR

1. IN THIS LESSON WE SHALL LOOK AT THE FOLLOWINGS;

– TYPE OF LANDING GEAR SYSTEM.

– CONSTRUCTION OF SKID TYPE LANDING GREAR.

– INSTALLATION OF SKID TYPE LANDING GEAR

– MAINTENANCE OF SKID TYPE LANDING GEAR.



FIREWALLPICTURE ON THE LH SIDE SHOWS THE CONSTRUCTION OF FIREWALL ON BELL430 HELICOPTERTHE FIREWALL IS NORMALLY FIITED TO ENGINE COMPARTMENT.ITS PURPOSE TO CONTAIN ANY FIRE FROM SPREADING TO THE AIRFRAME SHOULD IT OCCURS..



FIREWALL ON BELL 430THE FIREWALL IS NOT ONLY USED TO PROTECT THE CABIN BUT IS ALSO USED TO PROTECT ANY PIPELINES THAT MIGHT RUNNING IN BETWEEN THE ENGINE



CONSTRUCTION OF FIREWALLIN OLDER HELICOPTERS, FIREWALL IS NORMALLY CONSTRUCTED FROM STAINLESS STEEL.MODERN HELICOPTERS USING TITANIUM IN THE CONSTRUCTION OF FIREWALL AS THEY ARE MORE TEMPERATURE RESISTANT.IN ADDITION TO TITANIUM, FIREPROOF COMPOSITE HONEYCOMB IS ALSO USED AS IN THE CASE OF BELL 430THE MAIN DISADVANTAGE OF TITANIUM IS THAT IT’S DIFFICULT TO REPAIR.



FIREWALL INSTALLATION ON AS365N3


TITANIUM FIRAWALL


INSTALLATION & MAINTENANCE OF FIREWALL

1. FIREWALL IS NORMALLY ATTACHED TO THE ENGINE DECK BY MEANS OF FASTENERS WHICH ALLOWS EASY REMOVAL FOR ACCESS.

2. CARE SHOULD BE TAKEN DURING THE REMOVAL & INSTALLATION TO AVOID INJURY DUE TO SHARP EDGES.

3. PROPER INSTALLATION IS IMPORTANT BECAUSE LOOSELY FITTED FIREWALL MIGHT POSED A DANGER TO THE CABIN AND ITS PASSENGERS SHOULD FIRE OCCUR.



MAINTENANCE1. MAINTENANCE ACTIVITY ON THE FIREWALL WILL BE

SPECIFIED IN THE MAINTENANCE SCHEDULE.2. GENERALLY IT INVOLVES VISUAL INSPECTION ON THE

CONDITION AND INATALLATION OF THE FIREWALL ASSEMBLY.3. THE COMPOSITE HONEYCOMB FIREWALL GENERALLY

REQUIRE MORE INSPECTION AS IT CAN BE EASILY DAMAGED.4. NORMALLY REPAIRS ARE NOT FEASIBLE DUE TO THE NATURE

OF TITANIUM. DAMAGED FIREWALLS ARE NORMALLY REPLACED WITH NEW ONES



LANDING GEARTHIS LESSON WILL ONLY TOUCH THE SKID TYPE LANDING GEAR AS THE WHEELS TYPE LANDING GEAR HAS BEEN TOUCHED IN THE SUBJECT LANDING GEAR SYSTEM.IN GENERAL, HELICOPTER CAN BE FITTED WITH 2 TYPES OF LANDING GEAR NAMELY;1. SKID TYPE2. WHEEL TYPE.SKID TYPE IS NORMALLY USED ON SMALL HELICOPTERS DUE TO ITS SIMPLICITY BUT THE DISADVANTAGE WOULD BE IT RESTRICTED AIRCRAFT MOVEMENT ON GROUND.WHEEL TYPE IS USED ON MEDIUM TO LARGE SIZE HELICOPTERS AS IT ALLOWS GREATER MOBILITY OF THE AIRCRAFT AND IT CAN SUPPORTED MORE WEIGHT COMPARED TO SKID TYPE LANDING GEAR.



CONSTRUCTION OF SKID TYPE LANDING GEARTHE PICTURE ON THE LEFT SHOWS THE SKID TYPE LANDING GEAR FITTED TO BELL 412.IT IS MADE OF ALUMINIUM ALLYS AND CONSIST OS 2 PARTS; 2 LONGITUDINAL TUBES & 2 CROSSTUBES.IT IS SIMPLE, RUGGED AND VIRTUALLY MAINTENANCE FREE.IT IS DESIGNED TO ABSORB ENERGY AND PRECLUDE EXTENSIVE DAMAGE TO THE HELICOPTER IN THE EVENT OF HARD LANDING



CONSTRUCTION OF SKID TYPE LANDING GEAR (CONT)

ON SOME HELICOPTERS, THE SKID TYPE LANDING GEAR CAN EITHER BE THE LOW SKID TYPE OR HIGH SKID TYPE DEPENDING ON THE CUSTOMER REQUEST.

OTHER ACCESSORIES THAT MAY BE ATTACHED TO THE SKID INCLUDES THE FLOATATION EQUIPMENT, AND UNDERSLUNG UNIT.



Skid landing gear on MD 900


LANDING GEAR INSTALLATIONCOMPARED TO THE WHEEL TYPE LANDING GEAR THE SKID TYPE HAS FEWER PARTS WHICH MAKES INTALLATION A LOT SIMPLER.THE INSTALLATION PARTS MAY COMPRISE OF SHOCK ABSORBER WHICH IS USED TO MINIMISE THE GROUND RESONANCE. IN ADDITION, THICK RUBBER BLOCKS MAY BE PLACED BETWEEN THE CROSS-TUBES & THE FUSELAGE TO FURTHER ISOLATE VIBRATION GENERATED BY SKID FROM BEING TRANSFERRED TO THE FUSELAGE.



LANDING GEAR INSTALLATION ON AS 355THE TOP PICTURE ON THE LH SIDE SHOWS THE RUBBER BLOCK BEING PLACED BETWEEN THE CROSS-TUBE AND THE FUSELAGE.THE BOTTOM PICTURE MEANWHILE SHOWS THE INSTALLATION OF TWO SHOCK ABSOBERS.BOTH PLAY AN IMPORTANT ROLES TO REDUCE GROUND RESONANCE WHEN THE ROTOR IS RUNNING.



MAINTENANCE

DETAILS OF MAINTENANCE ACTIVITIES ON THE LANDING GEAR WILL BE STATED IN THE APPROVED MAINTENANCE SCHEDULE.MOST OF THE INSPECTION INVOLVE VISUAL INSPECTION WHICH NEED TO BE PERFORMED AT CERTAIN INTERVALS AND ANY DEFECTIVE PARTS MUST BE REPLACED.MOST COMMON PARTS THAT REQUIRE FREQUENT REPLACEMENT INCLUDE WORN SKID SHOES AND DETERIORATION OF RUBBER MATERIALSFOR SPECIFIC INSPECTION, IT USUALLY INVOLVES JACKING UP THE AIRCRAFT AND THROUGHLY INSPECTED THE COMPONENTS FOR DAMAGE SUCH AS CORROSION AND DEFORMATION.



MAINTENANCE (CONT)

EXAMPLE ON THE LEFT SHOWS THE TYPE OF INSPECTION THAT SHOULD BE PERFORMED ON AS355 SKID AND ITS DIMENSIONAL VALUE.


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