Actual Aircraft Maintenance Practices

FINAL YEAR REPORT
ON
ACTUAL AIRCRAFT MAINTENANCE PRACTICES

HONG KONG

June 2012

Contents

         Page

1. Objective                                        3
2. Introduction                                      3
3. Rudder and Rudder Trim Control System – Adjustment   4
   3.1 Reason for the task                                             4
   
   3.2 Review on the advice and/or conclusions from the incident/accident history 4
   
   3.3 Description of relevant system(s) or component(s)                     4
   
   3.4 Preparation work and procedure                                 4-8
   
   3.5 Use of aircraft maintenance documents in compliance with airworthiness   8     requirements
   
   3.6 Involvement of related knowledge or skills                           8
   
   3.7 Discussions                                                  8-9
   
   3.8 Development of solutions or recommendations to improve the quality of  maintenance                                                      9

1. Conclusions                                      9
2. References                                      

Objective

This report is the review of my maintenance work on actual aircraft under the supervision of qualified aircraft maintenance person. It let me learn a lot of practical experience and it is very useful for me in the industry. Also, it can lead more people understand my maintenance work.

Introduction

This report is my maintenance work at the Hong Kong Aircraft Engineering Company Limited (HAECO). HAECO has provided comprehensive aeronautical engineering and maintenance services to airlines and operators since 1950.

It is a full service provider at the new Hong Kong International Airport at Cheek Lap Kook offering comprehensive line to heavy maintenance packages including aircraft component overhaul support and AOG/aircraft recovery service.

From June 2008, I joined this company and started working at Base Maintenance and my team is belong to airframe team. Sometime we need to support the other trades, for example: Flight Control, Landing Gear, Engine and Cargo team. Therefore, I learn lots for experience from the maintenance work under the supervision of the qualified instructor.

My team major working area is empennage, so we had a lot of maintenance experience work for the Rudder, Elevator and Horizontal Stabilizer.

So the following part of the report, is the detail maintenance task that I had been done of my work.

Maintenance Task

Rudder and Rudder Trim Control System – Adjustment        

Reason for the task:

This task was done in Base Maintenance. The Aircraft type is Boeing B-767-300 and is owned by Delta Airline. The registration number is N185DN. This aircraft was undergoing a 4C check. During to the inspection, the inspector found out that a pair control cable of the Rudder was corroded and needed to be replaced. After replacing the cables, we need to carry out the adjustment according to the AMM 27-21-00.

Review on the advice and/or conclusions from the incident/accident history:

Rudder and Rudder Trim Control System provides directional control, stability around the vertical axis and indicated the rudder position on the EICAS status page from the rudder position transmitter. Therefore, we must carry out the adjustment to ensure the correct indication show on the display units for the pilots to control the aircraft and avoid out of control.

Description of relevant system(s) or component(s):

The two rudder control cables are attached at the left and right forward quadrants. The cables run under the flight deck, up the rear wall of the flight deck, and above the main deck compartment to the feel, centering, and trim mechanism aft quadrant. Their functions are transmit the force from forward quadrants to aft quadrant apply by the pilot. Then, transmit the force to the PCAs by the input rods and control the rudder movement.

Preparation work:

Before carrying out the task, we should set-up the job first. For example, what tools and equipment we needed to use and printed out the related AMM for this task. After that, they took me to the store to borrow the tools. We should only use the approved tools to carry out the maintenance job. According to the AMM, we need to use the rig pins, Towing Lever Lock Pin and Cable Tension meter.

As the old control cables were reject. Therefore, we should disconnect the old one and replaced by the new cables. Due to the cables were new, so we needed to adjust the cables tension up to twice about the normal rig load for about 24 hours to stabilize the cable tension.

After that, supply electrical power and asked the qualified person to move the tail flight control shutoff valve L, C, and R switches to OFF and attach warning tags. Then, Move the towing lever on the metering valve module to the tow position and install the towing lever lock pin in the nose gear and install rig pins into the control column torque tube to prevent accidental elevator movement.

Procedures:

After the preparation, we could start the adjustment. Then, we should adjust the Rudder Pedals and Jackshaft (Fig. 503). First, we adjusted the captain's pedals and jackshaft by disconnecting the control rods from the left and right rudder pedal arms and install rig pin into the quadrant. Then, adjust the control rods until the bolts can be easily installed through the rod end bearings at the pedal arms. After that, connect the control rods and tighten the jam nuts.

Then, repeat above step again for adjust the first officer's pedal adjustment crank.

After these step, we could remove the rig pins and cycle the rudder pedals. Make sure there is full quadrant travel between its stops and do an inspection on all the control rods. Make sure that control rod threads can be seen in at least one-half of the control rod inspection hole.

Then, we could move to next step to carry out the oscillation check of the Rudder Ratio Changer Actuator (RRCA). First, installed rig pin for the feel, centering, and trim mechanism and supply pressure to the left hydraulic system. Make sure that, keep persons and equipment away from all control surface when hydraulic power is supplied to prevent injury to persons or damage to the equipment. Then asked the qualified person to operating and test the Rudder Ratio Changer Actuator (RRCA) and observe the RRCA and Rudder Ratio Changer Output Arms for oscillations. If oscillations are noted, troubleshoot and correct the oscillation should carry out before complete this procedure. After that, we can remove the rig pin and move the left RRCM test switch to NORMAL and remove the power from the left hydraulic system.