Description

Activity 1
Considering the following operations, give examples of different types of inventory.

You will see that it is often more difficult to apply the terms to service-based organisations.

Organisation

Raw Material Inventory (RMI)
Work in Progress Inventory (WIP)
Finished Goods Inventory (FGI)
Car plant
Electrical components, paint sub- assemblies, systems, etc. Part-assembled cars, batches of spares, etc.

Fully assembled cars.
Spares and accessories for retail.
Restaurant
Fresh vegetables, meat, ingredients, beverages, etc Meals being made, food in ovens, frozen stocks and sauces, etc. Prepared items on
dessert trolley, take away orders, etc.

Garment
Manufacturer

Oil Refinery

Insurance Office

University

Hospital

Activity 2

Using product information obtained from web searches, compare three inventory management systems (or software packages) which could be purchased by the General Manager of a large state-run hospital. What are the claimed benefits of each system? What disadvantages might be experienced in using these approaches to inventory management and what resistance might be presented by staff?

Activity 3

ABC analysis. Follow the worked example in Slack (2004), pp. 432–433 and make sure you understand the concept. Construct a Pareto curve for the following stock list, taken from the gift section of a University shop, using value as the aim of your categorisation.

Note: This can of course be done manually, using graph paper – but software such as Excel will make it very quick and simple.

Stock Item Stock
Code Usage
Per Year
Unit Cost (£)
Calendar 1 128 7.5
Scarf 2 25 14.5
Baseball Cap 3 322 7.5
Mug (logo) 4 75 8.75
Pen Set 5 38 6.5
University Print (unframed) 6 44 25
University Print (framed) 7 38 45
Sweatshirt (XL,L,M and S 8 235 28.5
Academic Diary 9 220 4.5
File 10 575 4
T-Shirt (XL,L,M and S) 11 473 10
Polo Shirt 12 37 16.75
Paperweight 13 12 15
Notebook 14 275 2.5
Disposable Lighter (logo) 15 110 0.6
Brass Lighter (logo) 16 5 7.5
Ash Tray (glass) 17 12 7.5

Create your own classification boundaries and, for each category, create a specific inventory review policy.

Activity 4
DA (Discussion Activity) 2 hours

CASE STUDY
(Read the short case in Slack 6th Ed, on pages 294-295, ‘Air traffic control- a world class juggling act’ – Slack et al. “Operations Management”, 4th edition, Prentice Hall, 2004)
Air traffic control: a world-class juggling act
Air traffic controllers have one of the most stressful jobs in the world. They are responsible for the lives of thousands of passengers who fly every day in and out of the world’s airports. Over the last 15 years, the number of planes in the sky has doubled, leading to congestion at many airports and putting air traffic controllers under increasing pressure. The controllers battle to maintain “separation standards” that set the distance between planes as they land and take off. Sheer volume pushes the air traffic controllers’ skills to the limit. Jim Courtney, an air traffic controller at LaGuardia Airport in New York, says: “There are half a dozen moments of sheer terror in each year when you wish you did something else for a living”.
New York – the world’s busiest airspace
The busiest airspace in the world is above New York. Around 7500 planes arrive and depart each day at New York’s three airports, John F. Kennedy, LaGuardia and Newark. The three airports form a triangle around New York and are just 15 miles from each other. This requires careful coordination of traffic patterns, approach and take-off routes, using predetermined corridors in the sky to keep the planes away from each other. If the wind changes, all three airports work together to change the flight paths. Sophisticated technology fitted to most of the bigger planes creates a safety zone around the aircraft so that when two aircraft get near to each other their computers negotiate which is going to take action to avoid the other and then alert the pilot who changes course. Smaller aircraft, without radar, rely upon vision and the notion of “little plane, big sky”.
During its passage into or out of an airport, each plane will pass through the hands of about eight different controllers. The airspace is divided into sectors controlled by different teams of air traffic controllers. Tower controllers at each airport control planes landing and taking off together with ground controllers who manage the movement of the planes on the ground around the airport. The TRACON (Terminal Radar Approach Control) controllers oversee the surrounding airspace. Each New York air traffic controller handles about 100 landings and take offs per hour, about one every 45 seconds.
TRACON controllers
The 60 TRACON controllers manage different sectors of airspace, with planes being handed over from one controller to the next. Each controller handles about 15 planes at a time, yet they never see them. All they see is a blip on a two-dimensional radar screen, which shows their aircraft type, altitude, speed and destination. The aircraft, however, are in three-dimensional airspace, flying at different altitudes and in various directions. The job of the approach controllers is to funnel planes from different directions into an orderly queue before handing each one over to the tower controllers for landing.
Tower controllers
The tower controllers are responsible for coordinating landing and taking off. Newark is New York’s busiest airport. During the early morning rush periods, there can be 40 planes an hour coming into land, with about 60 wanting to take off. As a result there can be queues of up to 25 planes waiting to depart.
At LaGuardia, there are two runways that cross each other, one used for take off and the other for landing. At peak times, air traffic controllers have to “shoot the gap” – to get planes to take off in between the stream of landing aircraft, sometimes less than 60 seconds apart. Allowing planes to start their take off as other planes are landing, using “anticipated separation”, keeps traffic moving and helps deal with increasing volumes of traffic. At peak times, controllers have to shoot the gap 80 times an hour.
Most airports handle a mixture of large and small planes, and tower controllers need to be able to calculate safe take off intervals in an instant. They have to take into account aircraft type and capabilities in order to ensure that appropriate separations can be kept. The faster planes need to be given more space in front of them than the slower planes. Wake turbulence – mini-hurricanes which trail downstream of a plane’s wing tips – is another major factor in determining how closely planes can follow each other. The larger the plane and the slower the plane, the greater the turbulence.
Besides the usual “large” planes, controllers have to manage the small aircraft, business helicopters, traffic spotter planes and the many sightseeing planes flying over Manhattan, or up the Hudson towards the Statue of Liberty. The tower controllers have to control the movement of over 2000 helicopters and light aircraft that fly through New York’s airspace every day, being sure to keep them out of the airspace around each airport used by the arriving and departing aircraft.
Ground controllers
As an aircraft lands, if it is handed over to the ground controllers who are responsible for navigating it through the maze of interconnecting taxiways found at most international airports. Some airport layouts mean that planes, having landed, have to cross over the runway where other planes are taking off in order to get to the terminal. All this need careful coordination by the ground controllers.
Some pilots may be unfamiliar with airport layouts and need careful coaxing. Worse still is poor visibility, fog or low cloud. At Kennedy airport, the ground radar does not show aircraft type, so the controllers have to rely upon memory and constant checking of aircraft position by radio to ensure they know where each aircraft is at any time.
Stress
Dealing continually with so many aircraft movements means that controllers have only a split second to analyse and react to every situation, yet they need to be right 100 per cent of the time. Any small error or lapse in concentration can have catastrophic consequences. They can’t afford to lose track of a single aircraft, because it may stray into someone else’s air space and into the path of another aircraft. If the computer projects that two planes are about to fly closer than three miles, the Conflict Alert buzzer sounds and the controllers have just seconds to make the right decision and then transmit it to the pilots. Sometimes problems arise in the planes themselves, such as an aircraft running short of fuel. Emergency landing procedures cover such eventualities. At Kennedy airport, they have about one such incident each day. As one controller remarked: “it’s like an enhanced video game, except you only have one life”.

Questions
Q1. Discuss and critically evaluate the planning activities involved in the case of air traffic control.
Q2. Discuss the specific control activities undertaken by the air traffic controllers and assess the impact of losing control on a particular aircraft to the other planes.
Q3. How would you critically evaluate the different problems that TRACON, tower and ground controllers face?

Sample Solution