Module 7 essay questions 1.Describe how you would make a hole in metal, composite and wood, discuss this in context of aircraft maintenance, state the precautions to be taken and include any limits or tolerances that the usage of these tools can achieve. 2.Describe the inspection in-situ of a brake unit, what would be your actions if you find a brake worn to limits. 3.Describe how tooling and equipment is controlled within a part 145maintenance organisation. 4.There is 2 inches of wet snow on the aircraft and light snow is still falling, the temperature is –2 deg, what are your considerations before releasing the aircraft for departure. 5.You notice that there is no hydraulic pressure indicated on the left system,details your actions. 6.There is water contamination in the fuel tank, how would you carry out awater fuel contamination test and what are the other tests you could carry out, describe any follow-up actions if contamination is found and continues in the future. 7.Micrometers and dial test indicators are used as precision equipment discuss the use of these equipment, their limitations and state the precautions to betaken when using them. 8.On a major hangar inspection, you fi nd corrosion on a panel on an un- pressurised area of the fuselage, detail your actions to return the aircraft to service. 9.Describe how you would replace an electronics card, and the precautions you would take. 10.Describe the problem of HIRF and discuss the design features of protection against HIRF. HIGH INTENSITY RADIATED FIELD (FIRF) Discuss the methods of protection against HIRF and the checks/ inspections which would be carried out after a fault was entered in the technical log. INTRODUCTION
High Intensity Radiated Field (HIRF) is produced by high energy systems located ont h e ground and occurs at all frequencies. It affects any electronic and d i g i t a l systems on the aircraft, causing affected systems to operate erratically. PROTECTION
Aircraft and systems can be protected against HIRF by
proper shielding of cables,E M I fi l t e r s , g o o d b o n d i n g , e l e c t r o s t a t i c d i s c h a r g e r. P r o p e r t e r m i n a t i o n o f a i r c r a f t s y s t e m connectors and sealing of LRUs conducting surface o n windows, screening of cables. CHECKS/ INSPECTIONS
If a fault had been entered in the technical log as HIRF I would make the aircraft safei n accor dance wit h the Air cr aft Ma int enance M anual ( AMM) and r aise an y other paper work required. I would attempt to isolate the fault, debrief t h e a i r c r e w, i f necessary and confirm it is HIRF and not just a fault with the systems involved. Thetechnical log could be consulted to establish if there is a pattern of previous similar faults. If HIRF appeared to be the cause I would check the serviceability of EMIfilters, continuity check of shielding and bonding and carry out BITE (Built InTest Equipment) tests where possible to rectify the defect. And also check for the following: Detailed bonding resistance Using loop resistance tester to measure the loop resistance/ i m p e d a n c e measurement. Disassemble the connector to detect corrosion. Arrange to reconfirm loop position within the limit. Carry out related s y s t e m functional test. C ERTIFICATION
Any work carried out would be recorded and signed as the job progressed. If anyi t e m s w e r e r e p l a c e d c r o s s c h e c k t h e E A S A F o r m 1 o r F A A 8 1 3 0 - 3 f o r i t e m s airworthiness conformity and would be attached to paper work, part numbers GRN’s,s e r i a l n u m b e r s o n a n d o f f w o u l d b e r e c o r d e d . C R S w o u l d b e i s s u e d b y a appropriately authorized engineer and a statement would be made in the technical log to monitor the systems affected on the next flights. R EPORTING
As any occurrence of HIRF is an incident this must be reported to the CAA throught h e Mandatory Occurrence Report (MOR) scheme. I would also report it to t h e organisation HIRF programme.