曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
Mass of wing structure,
Systems, fuel
Determine
aerodynamic
shape#2
Span, Chord,
Section
Calculate structural
loads#2 Load cases
Design Load bearing
structure#2
Calculate
structural mass
#2
Mass of wing structure,
Systems, fuel
Wing box design,
Material volume, density
Determine
aerodynamic
shape#3
Span, Chord,
Section
Calculate structural
loads#3 Load cases
Design Load bearing
structure#3
Calculate
structural mass
#3
Mass of wing structure,
Systems, fuel
Why Projects Fail
12
Improving the Planning Process
Our research in the aerospace and defence field has shown that managers often become reluctant to
carry out detailed planning using existing planning tools because they often find it an unrewarding
and labour intensive activity. This is primarily because existing tools cannot adequately represent the
detailed information flows and iterative dependencies that are typical of real projects. Resource
requirement estimates are often seen as entirely notional, with the highly negative consequence that
the estimating process is not taken seriously enough. On occasion such estimates are literally “plucked
from thin air”.
A considerable amount of the planning effort is wasted in translating the real complexities of the
project workflow to a level of abstraction that existing planning tools can cope with. This subtle, but
very important limitation, results in a plan, which cannot show the detail that most stakeholders need,
expect and are familiar with. This leads to a downward spiral where stakeholders have difficulty
accepting and committing to a plan, which they don’t recognise as representing the real project. One
could describe this as a problem of ontology, as the plan is literally not an accurate model of reality.
Inevitably timescales for deliverables are error prone, because the very tasks in the plan are not
accurately described. This problem can be mitigated to some degree by what is known as ‘defensive
scheduling’, where some “slack” is built into timescales. But in civil aerospace, where sales to
customers have been premised on tight timescales, defensive scheduling is often not acceptable.
In the scenario we are describing, as the project progresses stakeholders become increasingly
unwilling to update the plan, because there is an irreconcilable divergence between the plan and
reality. Planners quickly become frustrated because of the reluctance of the organisation to adhere to
and update the original plan, which often gets abandoned. Therefore it is clear that projects must
begin with a planning process that avoids this divergence, starting out with a plan that stakeholders
throughout the organisation can identify with; there can be no missing detail and the inputs of all
stakeholders must be represented
Realistic representation
The authors believe that effective planning tools should have no restriction on the complexity of
dependency networks that can be generated. Trials of a prototype tool with the aerospace industry
have shown that this has a dramatic effect on the motivation amongst participants to capture and
model the information dependencies within their domain.24 In our experience engineers and activity
owners develop a sense of ownership through modelling the workflows in terms that they recognise
and at a level of abstraction that is relevant to them. These stakeholders develop a deeper appreciation
of the upstream and downstream information flows that concern them. Furthermore, because the
initial planning model in our methodology, (the network), is not based on a calendar or timeline there
is less defensive behaviour or concern over timescale commitments. This leads to an ethos and
atmosphere, which is more likely to stimulate the sharing of project knowledge. In other words the
correct kind of planning is beneficial to knowledge management. Although the Planner that was
trialed by the authors encourages users to generate a very detailed network, the compact
representation used results in a network that is not significantly bigger than that used by current
planning tools.
We recognise that the approach we are advocating will require a major effort at the front end of
projects and a corresponding change in cultural attitudes. Discussions with project managers at a
major UK engineering company suggested that this is where one of the greatest challenges lies. We
were informed that our system was undoubtedly superior in technical terms, but that strong cultural
resistance to the recommended way of working would be apparent. We find this response troubling. In
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
航空资料41(79)
