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Project Management
Planning & Control
SureFli Case Study1
1 Copyright H.A.Ainsworth April 1999, 2002
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SureFli Ground Services PLC
1.0 IntroductionSureFli Ground Services PLC has been providing a
wide range of services at airports andto airline companies.
Recently it has expanded its operations into the field of
aircraft
maintenance.The Civil Aviation authorities require that all
aircraft are subjected to rigorousmaintenance inspection at
stipulated regular intervals.The expansion is part of the long term
strategy of SureFli in accordance with its missionto be ... the
leading provider of a complete range of high quality civil aircraft
services....The timing of the decision to proceed coincides with an
opportunity to tender for a fiveyear contract to provide the
maintenance for the Airbus fleet of a major internationalpassenger
airline.
1.1 Company OrganizationThe current company organisation
structure is shown below. The new division is to be
called Aircraft Maintenance. Each division is headed by a
director with a place on theBoard of Directors.
C a t e r i n g
D i v i s i o n
A i r p o r t R e t a i l
S e r v i c e s
D i v i s i o n
C a r g o H a n d l i n g
D i v i s i o n
S u r e F l i
B o a r d o f D i r e c t o r s
1.2 The Proposed Aircraft Maintenance DivisionBefore
establishing this division a feasibility study is to be conducted
which will need toevaluate a range of problematic areas and propose
viable solutions. It is clear from
discussions held with the airline that turn-round time, safety
standards and emergencysupport will be key factors when the tenders
are examined.The Director himself has taken charge of the project
to put together a tender as he has hadsome experience of project
management and feels the sensible application of thetechniques will
give the best possible chance of success. However you have
beeninstructed to carry out the feasibility study project with the
brief to examine a range ofissues, namely turn-round time,
staffing, costs, project structure, quality assurance, costand time
monitoring methods etc.
1.3 Aircraft MaintenanceThe requirements, spelled out in the
tender documents, cover full maintenance of the
aircraft engines, its airframe and fuel tanks and all landing
gear. After the aircraft has beenchecked in and all the relevant
data recorded it will be moved to a maintenance hangar
andpositioned ready for work to begin. The first activities are
concerned with conducting adetailed inspection of all the three
areas of concern by suitably qualified inspectionengineers. From
this a complete list of required rectifications is produced for the
relevantfitters to perform. Once the rectifications have been done
thorough checking is carried outbefore the aircraft is signed off
and moved from the hangar ready to resume service.Clearly it is
desirable to minimise the loss of income incurred by the airline by
completing
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the maintenance as quickly as possible. However safety should
never be compromised forthe sake of shorter turnaround.
2.0 Project DataAs a first step in the planning process the
Project Manager should develop a first levelWork Breakdown
Structure (see Fig 1 below) before proceeding to gather detailed
data.
The packages at the first level may be called Phases, Stages or
whatever is mostappropriate. As the lower levels of the structure
are produced and the work packagesbroken down into activities or
tasks vital data is recorded for later analysis.
P r e p a
A i r c r a
I n s p e
A i r c r a
R e c t i
A i r c r a
C h e c
R e c t i f i c
M a i n t e
Figure 1
Further analysis of each work package produces the second level
of the WBS shown inFigure 2 overleaf.
The packages at the second level might be called Activities (see
Table 1 over for adetailed description of each activity). Chapter 4
of Burke gives a thorough evaluation ofWBS (see also Chapter 9 of
the MBA Project Management study guide).
A
P r e p a r e
A i r c r a f t
B C D
I n s p e c t
A i r c r a f t
E F G
R e c t i f y
A i r c r a f t
H
C h e c k
R e c t i f i c a t i
M a i n t e n a
Figure 2
Exercise 2
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Work Package
Second Level
Project Title
Activities
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By considering the breakdown of the Aircraft into its main
maintenance parts try todevelop an alternative WBS for
SureFli.Discuss the organisational structure issues which arise
from these two approaches?
More detailed investigation produces the activity data given
below:
Activity Description Duration(days)
InspectionEngineers
Fitters
A Position & jack up aircraft. Clean undercarriage&
remove wheels
2 - 4
B Inspect engines 2 1 3C Inspect airframe 4 2 1D Inspect
undercarriage 2 1 3E Rectify airframe 4 - 3F Rectify engines 3 - 2G
Rectify undercarriage & refit wheels 4 - 1H Check rectification
& sign off 2 3 1
Table 1.
2.1 Project LogicAfter the construction of the WBS for the
project more detailed analysis will be neededbefore we can
determine how long the project will take and how much it will
probablycost. This entails not only collecting the above data but
also establishing the logicalrelationships between activities.
Essentially all one has to ask about any particular activityis
Which activities are stopping it from starting?. These activities
are called theimmediate predecessors.
Exercise 2.1 In the table below three predecessors have been
entered, complete the table
for the other five activities:
Activity Description ImmediatePredecessors
A Position & jack up aircraft. Clean undercarriage &
remove wheels NoneB Inspect engines AC Inspect airframe
D Inspect undercarriage
E Rectify airframe
F Rectify engines BG Rectify undercarriage
HCheck Rectification
Table 2.
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2.2 Network ConstructionFrom the predecessor data a graphical
representation of the logic can be produced usingeither
activity-on-node (boxes) or activity-on-arrow (arrows) to represent
activities.Currently all commercial software uses the former for
network construction.The network, using the activity-on-node
method, which is also known as precedencediagramming, is shown
below.
Figure 3.
Exercise 2.2.
Draw the activity-on-node network for each of the following
projects.i) A company specialising in the erection of swimming
pools has broken the activitiesdown as shown below. (Source:
Project Management Study Guide, Chapter 6 Task 1).
Activity Predecessors Duration (weeks) Staff Required
A - 2 2B - 4 3C A 3 2
D A 5 4E A 1 3
F C 2 3G D 5 3H B,E 7 3I H 2 2J F,G,I 3 1
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B F
start A C E H end
D G
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ii) (Optional) A heavy engineering company has undertaken to
install a large turbine at apower station. A breakdown of the
activities with estimated durations and their respectivecosts is
given below. (Source: Project Management Study Guide, Chapter 6,
Task 2)
Activity Predecessors Duration (weeks) Costs (000)
A - 6 120
B - 5 50C - 4 60D A 4 60
E B 8 60F B,C 8 136G D,E 7 96H F 4 56I H,G 3 64
2.3 Network AnalysisNetwork Analysis, also known as Critical
Path Analysis (CPA), is carried out in twostages.
1. Starting with the first activities and passing forwards
through the network it is nowpossible to determine the Earliest
Start (ES) times for every activity. The earlieststart time for H
added to the time H is estimated to take will give us the
EarliestFinish (EF) time for the project (i.e. its duration).
2. A backward pass starting with H will enable us to find the
Latest Start(LS) timesfor every activity. The Latest Start for each
activity is found by subtracting itsduration from the Latest Start
Time of its immediate successor. For example DsLS is Gs LS minus Ds
duration i.e. 6-2=4. Should an activity have more than
one immediate successor the one with the earliest LS (i.e.
smallest numerically)will decide that activitys LS.
Activities where ES=LS have no scope for delay and are said to
be Critical - suchactivities are said to have zero Float.
Activities with scope for delay will have LS > ES.They are said
to havefloat.
The definition ofTotal Float is LS minus ES ( LS ES ). The
sequence(s) of activitieswith no float form what is known as the
Critical Path(s). Activities with float are callednon-critical
these are the tasks which can be delayed without the project
finishing late.
It should be noted that any particular float is usually shared
by a sequence of activities;thus if one non-critical activity is
delayed this will normally result in a reduction in thefloat of
succeeding activities.
From the earliest and latest start times we can also find the
Earliest and Latest Finishtimes (EF & LF) for each activity.
Together these provide the manager with valuableinformation for
planning and controlling the project.
The full critical path analysis for SureFli is shown on the
network below:
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Figure 4.
From this we can see the project will take 12 days and the
Critical Path is A-C-E-H.
Exercise 2.3Carry out the critical path analysis for the two
projects from Exercise 2.2.
2.4 Network InformationWe can display the CPA in tabular form as
on occasions it is more useful to the manager.
A partly completed tabulation of the results is shown in Table
3.
Activity Duration Earliest
Start
Latest
Start
Earliest
Finish
Latest
Finish
Total
Float
A 2 0 0 0
B 2 2 5 3
C 4 2
D 2 2
E 4 6
F 3
G 4
H 2
Table 3
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ES
2 4 TSK Dur
B 2 F 3 LS TF
5 3 7 3
0 0 2 6 10 12
start A 2 C 4 E 4 H 2 end
0 0 2 0 6 0 10 0 12
2 4
D 2 G 4
4 2 6 2
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Another valuable way of presenting the information both to
members of the project teamand management alike is the Gantt chart.
Using time on the horizontal axis this graphicalform lays out a bar
for each activity set at the Earliest Start time with length
representingthe duration. Activities A and B have been drawn on the
Gantt Chart below.
Days of the Project
Figure 5
Exercise 2.4a) Complete Table 3 and the Gantt Chart, Figure 4.b)
Consider each of the following and discuss their individual effects
on the total project
time:i) Extra work is required rectifying the undercarriage
which will take one day
longer than expected.ii) Inspection and rectification of
airframe takes only 6 days.iii) Due to an emergency on an
operational aircraft the engine inspection is
delayed and does not start until the beginning of the 7th
day.
3.0 Resource PlanningBy superimposing the resources required by
each activity onto the Gantt chart above wecan determine the
resource requirements for each day of the project - this is called
theforward load on resources. Table 4 shows the results for
Inspection Engineers ( *indicates activities with Float):
Activity 1 2 3 4 5 6 7 8 9 10 11 12
A 0 0B 1 1 * * *C 2 2 2 2
D 1 1 * *E 0 0 0 0F 0 0 0 * * *G 0 0 0 0 * *H 3 3
Total 0 0 4 4 2 2 0 0 0 0 3 3
Table 4
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Task 1 2 3 4 5 6 7 8 9 10 11 12
A = = = =
B = = = = :::::: :::::: ::::::
C
D
E
F
G
H
Float
Critical
Non-critical
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Exercise 3.1
Complete the resource analysis table for the forward load on
resources for the Fitters.
Activity 1 2 3 4 5 6 7 8 9 10 11 12
A
B
CD
E
F
G
H
Total
For this particular schedule we can see that the maximum number
of Inspection Engineersrequired is 4 and also that there is uneven
utilisation of the fitter resource. This shows upclearly in the
histogram of the forward load on the resources (see Graph 1).
Graph 1This can be smoothed by delaying non-critical activities.
If the company has limitedresource the load on resources can be
levelled by delaying non-critical and also criticalactivities if
necessary. The latter will of course extend the duration of the
project.
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RESOURCE HISTOGRAM
0
1
2
3
4
5
6
7
8
1 2 3 4 5 6 7 8 9 10 11 12 13
DAY
MEN
Fitters
Inspection Engineers
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When activities are delayed it is vital to look at the
implications for successor activities asthey will have to be
delayed also.
Exercise 3.2a) By delaying selected non-critical activities
smooth the load on Fitters.b) If SureFli decide they only wish to
employ 5 Fitters can they still complete the aircraft
maintenance in 12 days? If so what is the schedule? If not what
is the shortest totalproject time and what is the schedule?
c) Construct a resource analysis table and histogram for
Exercise 2.2(i) (see Page 5).Determine if it is possible to
complete the project in the shortest possible time withoutever
employing more than ten staff simultaneously on the site.
4.0 Project CostsIt is now possible to do some cost estimating
based on the activity data using appropriatecharge out rates for
the engineers and fitters; in this case it was decided after
consultationwith the Accounting Department that 250 and 200 per day
respectively should be used.In addition some estimate of the costs
of materials and spare parts that are likely to be used
also needed including
The estimated costs in 00 for each activity including labour,
materials and/or replacementparts is shown in Table 5.
Activity LabourCosts
OtherCosts
TotalCost
A 16 1 17B 17 0.6 17.6C 28 28
D 17 1.2 18.2E 24 9 33F 12 12G 8 8 16H 19 19
Table 5.
Using this data we can calculate the cumulative costs for the
project on a day-by-daybasis. This information is useful in
identifying any potential difficulties the company mayhave with
cash flow and could also be used as part of the control process
once the project
is up and running.
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Table 6 shows the breakdown of costs on a daily basis note it
has been assumed that thecosts are distributed evenly over the
duration of each activity. The cumulative costs areshown in the
graph below.
Days
1 2 3 4 5 6 7 8 9 10 11 12Activity
A 850 850 0 0 0 0 0 0 0 0 0 0
B 0 0 880 880 0 0 0 0 0 0 0 0
C 0 0 700 700 700 700 0 0 0 0 0 0
D 0 0 910 910 0 0 0 0 0 0 0 0
E 0 0 0 0 0 0 825 825 825 825 0 0
F 0 0 0 0 400 400 400 0 0 0 0 0
G 0 0 0 0 400 400 400 400 0 0 0 0
H 0 0 0 0 0 0 0 0 0 0 950 950
Total
Cost
850 850 2490 2490 1500 1500 1625 1225 825 825 950 950
Cum.Tot.Costs
850 1700 4190 6680 8180 9680 11305
12530
13355
14180
15130
16080
Table 6.
Graph 2.
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SureFli
Cumulative Costs
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
0 5 10 15 20
Days
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Exercise 4.Construct the cost table forExercise 2.2 (i) if the
swimming pool company charges out itsstaff at 500 per week and
hence draw the cumulative costs graph.
5.0 Improving The Plan
The data in Table 1 formed the basis for our first plan. The
next stage is to try to improvethat plan. Each of the activities
involved was examined in turn and alternative (crash)durations,
together with the necessary resources and costs were estimated.
These areshown in Table 7 below:
Activity CrashDuration
Inspection
Engineers
Fitters Estimated TotalCost ($)
A 1 - 9 1900C 2 2 6 3400
E 3 - 6 4500F 2 - 4 1600G 2 - 3 2000
Table 8
By examining the critical path and selecting the most
cost-effective activity to crash theduration of the project can be
decreased thus potentially reducing the overhead costs. Thiswill
provide management with a range of options from which the final
schedule can bechosen after having given full consideration to the
resource implications and any necessarytime-cost trade-offs. A
characteristic of crash programmes is that inevitably the risk in
theproject is increased.
Exercise 5.5.1 For SureFlia) Determine what alternative
schedules are available and their respective total costs.
b) Find the quickest schedule and its total cost.
c) If the contract states that there will be a penalty of 1000
per day for each day that theproject takes in excess of 7 days what
is the lowest total cost schedule? What is thelowest cost schedule
if the penalty is 2000 per day?
d) If on the other hand the contract states that will be a bonus
payment of 2000 per dayfor each day under 12 days what is the
optimum schedule now?
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5.2 If a client of the swimming pool company offers a bonus
payment of 1000 for everyweek less than the normal finish date and
the following tasks can be crashed to thedurations given below for
the revised total costs shown finda) the minimum cost b) the
quickest schedules.
Task B D G H J
CrashDuration
3 4 3 5 2
CrashCost
7500 10500 9000 11500 2000
5.3 (optional) This exercise uses the problem scenario of
Exercise 2.2 (ii) (see Page 6).The data given in the question is to
be taken as the normal data resulting in a schedulewith duration 23
weeks at a project cost of $702,000 (see solution to Exercise 4
fromabove). At this stage of the planning you are informed that
there is penalty clause inthe contract of $19,000 per week for each
week the project lasts beyond 15 weeks (i.e.
the normal schedule above will incur a penalty of 8 x $19,000 =
$152,000) which willbe deducted from the agreed contract price.The
following crash cost data is to be used to determine what
alternative schedules arepossible and to decide ona) the minimum
cost scheduleb) the quickest schedule.
Activity A B E F G HCrash Duration 4 4 5 6 5 3Crash Cost ($000)
160 60 84 170 120 70
6.0 Monitoring the ProjectVarious approaches are available
depending on the size and complexity of the project. Forsuccessful
control three areas must be considered: The original budgeted costs
which give a baseline against which to measure The actual costs
i.e. the money spent doing The work carried out.
Only Earned Value Analysis (see Burke Chapter 16) integrates
both Time and Cost controlinto one comprehensive framework. In this
approach at appropriate times comparison ismade with the baseline
costs using the following parameters
Budget at Completion (BAC) the original planned
expenditureBudget Cost for Work Scheduled (BCWS) the original
planned cost of the work thatwas planned to have been done by that
time.Budget Cost for Work Performed (BCWP) the work that has
actually been completedby that time costed at the original budgeted
rate.Actual Cost for Work Performed (ACWP) the amount spent
achieving the workcompleted by that time.
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From this key data a set ofvariances can be calculated which can
be used as indicators ofachievement, an explanation of some of the
basic ones follows.Firstly we look at those concerned with
monitoring time: Schedule Variance (SV) = BCWP - BCWS SV% =
SV/BCWS*100
A negative SV indicates the project is lagging behind the
planned schedule in some way.However it does not necessarily follow
that the project will overrun the plannedfinish date as the delays
may have been in non-critical activities.
Secondly we consider the variances which monitor the project
costs: Cost Variance (CV) = BCWP - ACWP CV% = CV/BCWP*100
Here again a negative CV indicates a cost overrun.
Finally we have
Estimate at Completion (EAC) the best estimate at that time of
how much the project isgoing to cost, initially this will be the
same as BAC but later must take into account theperformance during
the project so far as follows:EAC = BAC * ACWP / BCWP and
Variance at Completion = EAC - BAC
Exercise 6.a) After 6 days activities A, B, C and D are
completed. No other activities have been
started. The total activity costs incurred so far are 8100.
Further investigation findsthat the start of both B and D was
delayed by 2 days because of an emergency. Othercosts for activity
A were 120. Other activity costs as planned. Perform an earnedvalue
analysis.
b) The swimming pool project manager decides to monitor the
project (Ex 2.2 (i) normaldurations) on a 3 weekly basis. After 3
weeks he finds that activities A, B and E arecompleted, no other
activity having yet started. The total expenditure so far has
been9750. Report on the projects progress making any
recommendations you considerappropriate.
c) For Exercise 2.2 (ii) carry out an EVA given that after 13
weeks activities A, B and Care completed, D, E and F are half
complete and activities G, H and I have not yetstarted. The total
expenditure so far has been $400,000.
7.0 Project OrganisationEven experienced practitioners find it
difficult to explain how one should proceed when
choosing the organisational structure for a project. The choice
is determined by the
situation, but even so is partly intuitive. There are a few
accepted principles of design, and
no step-by-step procedures that give detailed instructions for
determining what kind of
structure is needed and how it can be built. All we can do is
consider the nature of the
potential project, the characteristics of the various
organisational options, the advantages
and disadvantages of each, and make the best compromise we
can.
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In general, the functional form is apt to be the organisational
form of choice for projects
where the main focus must be on the in-depth application of a
technology rather than, for
example, on minimising cost, meeting a specific schedule, or
achieving speedy response to
change. Also, the functional form is preferred for projects that
will require large capital
investments in equipment or buildings of a type normally used by
the function.
If the firm engages in a large number of similar projects (e.g.,
construction projects), the
pure project form of organisation is preferred. The same form
would generally be used for
one-time, highly specific, unique tasks that require careful
control and are not appropriatefor a single functional area - the
development of a new product line, for instance.
When the project requires the integration of inputs from several
functional areas and
involves reasonably sophisticated technology, but does not
require all the technical
specialists to work for the project on a full-time basis, the
matrix organisation is the only
satisfactory solution. This is particularly true when several
such projects must share
technical experts. But matrix organisations are complex and
present a difficult challengefor the PM. They should be avoided
when simpler organisational structures are feasible.
In choosing the structure for a project, the first problem is to
determine the kind of work
that must be accomplished. This is best done by first
identifying the primary objective(s)
of the project and then determining the major tasks associated
with each objective. Next,
this work can be decomposed into work packages. We can then
consider just what
individual organisational elements or subsystems will be
contained within the project.
Additional items to consider are the individuals doing the work
and their personalities, the
technology to be employed and the clients to be served.
Environmental factors inside and
outside the parent organisation must also be taken into account.
By understanding the
various structures, their advantages and disadvantages, a firm
can select the organisationalstructure that seems to offer the most
effective and efficient choice.
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Since it is our objective to provide criteria for the selection
of a project oroanisation, we
shall illustrate the process with two Case Studies (see Appendix
A). In each case, we use
the following approach.
1. Define the project with a statement of the objective(s) that
identifies the major
outcomes desired.
2. Determine the key tasks associated with each objective and
locate the units in the
parent organisation that serve as functional home for these
types of tasks.
3. Arrange the key tasks by sequence and decompose them into
work packages.
4. Determine which project subsystems are required to carry out
the work packagesand which subsystems will work particularly
closely with which others.
5. List any special characteristics or assumptions associated
with the project
- for example, level of technology needed, probably length and
size of the project,
any potential problems with the individuals who may be assigned
to the work,
possible political problems between different functions
involved, and anything else
that seems relevant, including the parent firms previous
experiences with different
ways of organising projects.
Exercise 7.
i) In light of the above and the analysis carried out discuss
the pros and cons of the variousorganizational structures for
SureFli.ii) Study the Case Studies in Appendix A and propose a
suitable organizational structurefor each.
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Appendix A
The Trinatronic Co.And
An Urban Hospital
Case studies in project organisation
Based on studies described in Meredith J.R, Mantel S.J., Project
Management: AManagerial Approach, Wiley (1995)
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TRINATRONIC. INC
Project objective: To design, build and market a multi-tasking
PC with a 64-bit processor,128 Mbytes RAM, and at least 20 Gbytes
of disk space to retail at $2,000 or less.
Key Issues
A. Write specifications.B. Design hardware, do initial
tests.C. Engineer hardware for
production.D. Set up production line.E. Manufacture small
run,
conduct quality and reliabilitytests.
F. Write (or adopt) operatingsystems.
G. Test operating systems.H. Write (or adopt) operating
systems.I. Test applications software.J. Prepare full
documentation,
repair and user manuals.
K. Set up service system withmanuals and spare parts.
L. Prepare marketingprogramme.
M. Prepare marketingdemonstrations
Organisational Units
Mktg. Div. And R&DR&D
Eng. Dept., Mfg. Div.
Eng. Dept., Mfg. Div.V.P. staff
Software Prod. Div.
Q.A. Dept, Exec. V.P. staffSoftware Prod. Div.
Q.A. Dept, Exec. V.P. staffTech. Writing Section (EngDiv) and
Tech. WritingSection (Software Prod.Div.)Service Dept., Mktg.
Div.
Mktg. Div.
Mktg. Div.
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Without attempting to generate a specific sequence for these
tasks , we note that they seem
to belong to four categories of work
1. Design, build and test hardware.
2. Design, write and test software.
3. Set up production and service/repair systems with spares and
manuals.
4. Design marketing effort with demonstrations, brochures and
manuals.Based on this analysis, it would appear that the project
will need the following elements:
Groups to design the hardware and software.
Groups to test the hardware and software.
A group to engineer the production system for the hardware.
A group to design the marketing programme.
A group to prepare all appropriate documents and manuals.
And, lest we forget, a group to administer all the above
groups.
These subsystems represent at least three major divisions and
perhaps a half-dozendepartments in the parent organisation. The
groups designing the hardware and themultiple operating systems
will have to work closely together. The test groups may workquite
independently of the hardware and software designers, but results
seem to improvewhen they cooperate.
Trinatronics has people capable of carrying out the project. The
design of the hardwareand operating systems is possible in the
current state of the art, but to design suchsystems at a cost will
allow a retail price of $2,000 or less will require an advance in
thestate of the art. The project is estimated to take between 18
and 24 months, and to be themost expensive project yet undertaken
by Trinatronics.
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URBAN HOSPITAL
Project objective: To develop and implement a computerised
scheduling system for thehospitals operating rooms.
Key Issues
A. Find and prioritise objectives ofthe system.
B. Build preliminary model.C. Program and testpreliminary
model.D. Use model in parallel with current
scheduling system.E. Compare results and present to
Dept. of Surg.F. If necessary, amend model and
repeat tasks D and E.G. Install model, including full
documentation.H. Train Dept. of Surg. clerks in
operation of model.
Organisational Units
Syst. Anal., Admin. Dept., andDept. of Surg.Syst. Anal., Admin.
Dept.Syst. Anal., Admin. Dept.
Syst. Anal., Admin. Dept.
Syst. Anal., Admin. Dept., andDept. of Surg.Syst. Anal., Admin
Dept., andDept of Surg.Syst. Anal., Admin. Dept.
Syst. Anal., Admin Dept., and Dept. of Surg
The order in which tasks should be performed is as shown above
because all the workmust be done sequentially. There are three
major jobs.
1. Build the model based on input from the users.
2. Test model on an as if basis and amend if necessary.3.
Install model and train operators.
Only two units will be required for the project, a systems
analysis group (housed in theDepartment of Administration) and a
user group. Analysts and users will have to worktogether throughout
the project. These groups each represent a different part of
theparent organisation.
Consideration was given to the use of an outside consultant to
analyse the system anddevelop the model. The internal systems
analysts are heavily involved in replacing anoutside vendors
accounting software system with one of their own devising. They
expect
to be fully occupied for another six to eight months. On the
other hand, some members ofthe Department of Surgery are worried
that the hospitals own analysts will not besensitive to the special
needs of the department and would be even less likely to
tolerateand trust outsiders. Indeed, several of the surgeons are
doubtful about the entire project.They are not sure that it makes
any sense to set priorities on the objectives for schedulingthe
operating rooms because quality of patient care is our only
priority.
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Suggested SolutionsExercise 2.
A
P r e p
B F
E n g i n
C E
A i r f r a
D G
U n d e r
H
C h e c
M a i n t
Exercise 2.1
Activity Description ImmediatePredecessors
A Position & jack up aircraft. Cleanundercarriage &
remove wheels
None
B Inspect engines AC Inspect airframe AD Inspect undercarriage
AE Rectify airframe CF Rectify engines BG Rectify undercarriage DH
Check Rectification E,F,G
Exercise 2.2 and 2.3 Complete Solutionsi) Critical Path B, H, I
and J . Shortest completion time 16 weeks
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2 5
C 3 F 2
8 6 11 6
0 16
0 2 7 13
start A 2 D 5 G 5 J 3 end
1 1 3 1 8 1 13 016
2 4 11
E 1 H 7 I 2
3 1 4 0 11 0
0
B 4
0 0
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ii)Quickest completion time is 23 weeks. Cost $702,000
Exercise 2.4a)
N.B. ES=Earliest Start, LS=Latest Start, EF=Earliest Finish,
LF=Latest Finish
b) Class exercise
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Task Duration ES LS EF LF Float
A 2 0 0 2 2 0
B 2 2 5 4 7 3
C 4 2 2 6 6 0
D 2 2 4 4 6 2
E 4 6 6 10 10 0
F 3 4 7 7 10 3
G 4 4 6 8 10 2
H 2 10 10 12 12 0
0 5 13
C 4 F 8 H 4
4 4 8 3 16 3
0 23
0 5 13 20
start B 5 E 8 G 7 I 3 end
0 0 5 0 13 0 20 0
23
0 6
A 6 D 4
3 3 9 3
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Exercise 3.1.
Exercise 3.2.
a)
b) No the project must be extended to 13 days by delaying B 2
days, F 4 days and H 1 day.
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Task TF 1 2 3 4 5 6 7 8 9 10 11 12
A 0 === ===
B 3 === === :::::::::::::::::::::
C 0 ============
D 2 === === ::::::::::::::
E 0 === === == ===
F 3 === === === ::::::::::::: :::::::
G 2 === === === === :::::: :::::::
H 0 === ===
Task Dur 1 2 3 4 5 6 7 8 9 10 11 12A 2 0 4 ======B 2 1 3
======::::::::::::::::::C 4 2 1 ========= ===D 2 1 3
::::::::::::=== ===E 4 0 3 ============F 3 0 2 === === ===
::::::::::::::::::G 4 0 1 ::::::::::::=== === === ===H 2 3 1 ===
===
Insp.Eng 0 0 3 3 3 3 0 0 0 0 3 3Fitters 4 4 4 4 6 6 6 4 4 4 1
1
Task 1 2 3 4 5 6 7 8 9 10 11 12 13
A == ==
B ::::: ::::: == == :::::
C == == == ==
D == == ::::: :::::
E == == == ==
F ::::: ::::: ::::: ::::: == == ==
G == == == == ::::: :::::
H ::::: == ==
Fitter 4 4 4 4 5 5 4 4 5 5 2 1 1
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c)
Exercise 4 All costs in '000sTask Costs 1 2 3 4 5 6 7 8 9 10 11
12 13 14 15 16
A 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
B 6 1.5 1.5 1.5 1.5 0 0 0 0 0 0 0 0 0 0 0 0
C 3 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0
D 10 0 0 2 2 2 2 2 0 0 0 0 0 0 0 0 0
E 1.5 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0
F 3 0 0 0 0 0 1.5 1.5 0 0 0 0 0 0 0 0 0
G 7.5 0 0 0 0 0 0 0 1.5 1.5 1.5 1.5 1.5 0 0 0 0
H 10.5 0 0 0 0 1.5 1.5 1.5 1.5 1.5 1.5 1.5 0 0 0 0 0
I 2 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0
J 1.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0.5 0.5
Total 47
Total Cost 2.5 2.5 6 4.5 4.5 5 5 3 3 3 3 2.5 1 0.5 0.5 1
Cum Cost 2.5 5 11 15.5 20 25 30 33 36 39 42 44.5 45.5 46 46.5
47
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Exercise 55.1 a), b), c) & d) Class5.2 First crash J then H
to give a new activity cost of 48500. As the CP is now ADGJ and
durationis 14 weeks you have gained 2000 in bonuses. Thus the real
cost is 46500. Now crash D(cheapest at this stage) giving duration
13 weeks and CPs of ADGJ and BHIJ. Net cost to date46000 this is
the least cost option. A quicker option is to now crash B & G
to finish in 12 weeks
but increase the net cost by 2000 to 48500.5.3 Begin by
identifying the Critical Path - these are the only activities worth
crashing initially or atany stage. Take an incremental approach
crashing one activity at a time and then examine the newcritical
path by doing the appropriate analysis - this is the only way you
can be sure that the savingsin time you are paying for are obtained
in practice. If it is not possible to shorten the critical path
inthis way it may be necessary to crash several activities
simultaneously - this only happens whenthere is more than one
critical path. In this way the following schedules can be
obtained:
Original 1 2 3 4 5 6
ActivitiesCrashed
None B G E A,B,E B,E,G,H A,B,E,G,F
Duration(weeks)
23 22 21 20 19 18 17
ActivityCost
702 712 726 726 776 774 834
PenaltyCost
152 133 114 95 76 57 38
TotalCost
854 845 840 821 852 831 872
Note: 1)All money figures are in $000. 2) Duplicate solutions
giving the same time are possible - only the overall
cheapest schedule is shown.
Exercise 6.(a) Class Exercise
(b)BCWS = 11, BCWP=9.5, ACWP = 9.75, SV= -1.5, CV= - 0.25 EAC=
47* 9.75/9.5Project Finishes in 16 weeks
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Budgeted Expenditure Work Done Actual Cost
BCWS BCWP ACWP BAC
A 120 A 120
B 50 B 50
C 60 C 60
D 60 0.5D 30
E 60 0.5E 30F 136 0.5F 68
486 358 400 702
Earned Value Analysis
edule Variance = 358 - 486 = -128
SV% = -12800 / 486 = -26.34%
ost Variance = 358 - 400 = -42
CV% = -4200 / 358 = -11.73%
Est. At Completion = 702 * 400 / 358 = 784
E 8/2
F 8/2
D 4/2
G 7 I 3 end
13
13
13
H 4
17
17
24 27
Completion time 27 weeks
Cost $702,000+42,000
= $744,000
