Maintenance Policy Part III

7/23/2019 Maintenance Policy Part III

1/6

Maintenance Policy

Health and usage monitoring systems

Health and usage monitoring systems (HUMS)is a generic term given to

activities that utilize data collection and analysis techniques to help ensure

availability, reliability and safety of vehicles. Activities similar to, or

sometimes used interchangeably with, HUMS include condition-based

maintenance (!M) and operational data recording (ODR). This term

H!" is o#ten used in re#erence to airborne cra#t and in particular rotor$

cra#t % the term is cited as being introduced by the o##shore oil industry a#ter

a commercial &hinoo' crashed in the orth "ea, 'illing all but two

passengers in *+. H!" are now used not only #or sa#ety but #or a

number o# other reasons including-

Maintenance- reduced mission aborts, #ewer aircra#t on ground(AO), simpli#ied logistics #or #leet deployment

ost" /maintain as you #ly0 maintenance #lights are not re1uired.

2er#orming repairs when the damage is minor increases the aircra#t

mean time before failure (M#!$)and decreases the mean time to

repair (M##%)&

'perational" 3mproved #light sa#ety, mission reliability and

e##ectiveness

erformance" improved aircra#t per#ormance and reduced #uel

consumption

AHealth Usage Monitoring System (HUMS)records the status o# critical

systems and components on helicopters so that the early detection o#

progressive de#ects, or indications o# them, is possible and thus recti#ication

can be achieved be#ore they have an immediate e##ect on operational sa#ety.

The on$board e1uipment stores data on a 2&!&3A &ard. 4or analysis, the

card is downloaded a#ter #light and maintenance analysis can then be

per#ormed on a ground$based computer. These systems were #irst deployed

in the early **5s as a response to the relatively poor continuing

airworthiness record and their introduction led to, and continues to support,signi#icant improvements in both sa#ety and reliability. A typical H!"

system uses sensors, distributed throughout the air#rame and its components,

which are lin'ed to a central computer unit with a data recording and storage

system. !onitoring trends in the recorded data is particularly important $ it

allows system specialists to determine whether the aircra#t has developed (or

is li'ely to develop) #aults that re1uire recti#ication.


2/6

The e6tent o# H!" data capture varies considerably. A basic system

collects some usage parameters such as ta'e$o##s, landings, engine starts and

winch li#ts as well as a small subset o# engine and transmission health data.

The most modern systems monitor the health o# all signi#icant vibrating and

spinning parts $ engines, gearbo6es, sha#ts, #ans, rotor systems $ and other

components. The operational conte6t o# events is recorded so that the trends

can be #ully analy7ed and maintenance crews are thus able to proactively

per#orm condition$based maintenance. The latest e1uipment allows the data

ac1uired to be processed onboard the aircra#t or at a ground station $ and

some systems allow it to be transmitted, whilst the helicopter is in #light, via

satellite communications to operator maintenance control units so that

subse1uent maintenance downtime can be minimi7ed by pre$planning. These

systems can also be con#igured to automatically report urgent or emergency

conditions to the operator and manu#acturer #rom anywhere in the world. An

e6ample o# a typical H!" system is brie#ly described in the re#erencebelow.

Planned maintenance

lanned reventive Maintenance (822!8) or more usual 9ust simple

Planned Maintenance(2!) or Scheduled Maintenanceis any variety o#

scheduled maintenance to an ob9ect or item o# e1uipment. "peci#ically,

lanned Maintenance is a scheduled service visit carried out by a

competent and suitable agent, to ensure that an item of equipment is

operating correctly and to therefore avoid any unscheduled breado*nand do*ntime.

Together with ondition !ased Maintenance, 2lanned maintenance

comprises preventive maintenance, in which the maintenance event is

preplanned, and all #uture maintenance is preprogrammed. 2lanned

maintenance is created #or every item separately according to manu#acturer:s

recommendation or legislation. 2lan can be based on e1uipment running

hours, date based, or #or vehicles distance traveled.

+ good eample of a planned maintenance program is car maintenance,

*here time and distance determine fluid change requirements&

+ good eample of ondition !ased Maintenance is the oil pressure

*arning light that provides notification that you should stop the vehicle

because failure *ill occur because engine lubrication has stopped&


3/6

2lanned maintenance has some advantages over &ondition ;ased

!aintenance such as-

Turnaround criti1ue communication. On$The$?ob planning enhancement #or day$to$day wor'. ?ob pac'age creation. "taging areas


4/6

3mplement @ey 2er#ormance indicators (@23:s). or' on e##ective use o# &!!". Hand$on support #or history documentation.

3mprovement o# technical database (;ill O# !aterials, technical data,e1uipment identi#ication, etc.)

3mprove integration with materials management &ontractor management and integration o# wor' processes.


5/6

Maintenance Planning and Scheduling

Maintenance planning and schedulingprioriti7es and organi7es wor' so it

can be e6ecuted in the most e##icient manner. 3t:s getting the right people in

the right place with the necessary tools, parts and in#ormation to per#orm the

re1uired tas'. The bene#its o# proper planning and scheduling include-

&ost savings due to e##icient use o# maintenance labor hours

3ncreased production yield #rom #aster e6ecution o# 9obs

Reduced in9uries and stress #rom a better wor' #low

!aintenance planning and scheduling are two activities that ensure theallocation o# needed resources and the se1uence in which they are needed so

any activity can be per#ormed in the shortest time with the least cost.

Although planning and scheduling are o#ten spo'en in the same breath, they

are two separate #unctions. 2lanning de#ines the HAT, H


6/6

re1uired wor'.

Backlog

!aintaining the bac'log is an important part o# the planning and scheduling

process. How well an organi7ation manages its bac'log demonstrates the

e##ectiveness with which it applies its resources to the highest priority wor'.

!any organi7ations have neglected bac'log and #ailed to reali7e its

importance in managing the maintenance wor' load. As a result they are

generally drowning in their own data. There are several common symptoms

o# poorly managed bac'log.

Scheduling

The purpose o# scheduling is to ensure that proper resources are available at

a speci#ic time when e1uipment on which the wor' to be done can also be

available. "imply stated, the HO and the H

Maintenance Policy Part III

Documents

Transcript of Maintenance Policy Part III