AAE5301 Chap.3 Service Networks and Tactical Decisions
Service Networks and Tactical Decisions
Classify the service before optimising it
Low-altitude services can cover vertiport-to-vertiport or first and last-mile legs and can run on schedules or in response to requests. Strategic decisions fix infrastructure, tactical decisions assign fleet and timetables, and operational decisions route, dispatch and charge.
This chapter shows how those horizons constrain one another and why a hybrid system needs an explicit interface rather than a vague claim that it combines flexibility and efficiency.
Separate geography, activation and horizon
The carried leg says where air transport enters the journey; the activation rule says whether capacity is committed before or after a request; the planning horizon says how often the decision can change.
These are independent classifications. A last-mile service can be scheduled, and a vertiport shuttle can be on demand. Keeping the axes separate prevents a label such as hybrid from concealing which customers wait, where transfers occur and which resources must be reserved.
Audit the interfaces
A service network is credible only when aircraft, customers and information can cross every hand-off.
Test ground access, transfer cut-offs, pad and charger conflicts, vehicle continuity and responsibility for a missed connection. Compare air time with door-to-door time and utilisation with recovery capacity. A tactical plan should pass clear limits to the dispatch layer, while observed operational failures should inform the next timetable or fleet decision.
What this chapter covers
- 01
Vertiport-to-vertiport service
- 02
First and last-mile service
- 03
Scheduled and on-demand modes
- 04
Strategic, tactical and operational horizons
- 05
Frequency and timetable decisions
- 06
Time-space vehicle continuity
Worked example · free
Design a hybrid inspection network
- 2Separate predictable and uncertain flows.
- 3Assign a mode and interface to each flow.
- 3Define reserve and performance measures.
Key terms
- Scheduled Service
- A service whose route, frequency or timetable is planned before requests occur.
- On-demand Service
- A service activated after a request and adjusted to current demand.
- Tactical Decision
- A medium-horizon allocation or scheduling choice constrained by strategic infrastructure.
- Frequency
- The number of services offered during a defined period.
- Time-space Node
- A representation of one location at one time used to preserve vehicle continuity.
Service Networks and Tactical Decisions FAQ
What is the difference between frequency and timetable?
Frequency states how many services operate in a period. A timetable assigns departure and arrival times to specific movements. Frequency can meet aggregate volume while a poor timetable still creates missed connections or pad conflicts.
Can repositioning be tactical and operational?
Yes. Overnight redistribution based on expected demand is tactical. A live movement triggered by a revealed shortage is operational. The same action changes horizon with information, timing and revision frequency.
Why can high utilisation be harmful?
Very high utilisation leaves little capacity for weather, charging delay or urgent demand. A network may look efficient on an average day and fail when flexibility is most valuable, so reliability must be priced or constrained.
How should a hybrid service interface be specified?
Name which leg uses each mode, where the transfer occurs, the cut-off or buffer, the resource reserved on both sides and the action after a miss. For example, a scheduled trunk may feed on-demand local delivery only when parcels arrive before a stated cut-off; late parcels need a defined storage and rebooking rule.
What does a time-space network add to a timetable?
It represents each location at successive times and connects them with movement or waiting arcs. Conservation at every time-space node prevents an aircraft from appearing for a departure without a feasible earlier arrival or initial presence. The same structure can expose charger occupancy, maintenance windows and repositioning continuity.
Which performance measures should compare service modes?
Use measures seen by both customer and operator: door-to-door time, waiting, completion reliability, missed demand, vehicle utilisation, reserve use and total cost. Report distributions or scenario results when averages hide disruption. The comparison must use the same demand, horizon and boundary; measuring only airborne time for one mode and full journey time for another is not valid.
Explain which service promise has priority before combining the measures into a score.
Exam move
Take each service case and label two axes: which leg the aircraft covers and how service is activated. Then place location, fleet, schedule, route and charging decisions on their planning horizons. Finish by naming the interface most likely to fail. Draw one time-space path for an aircraft and verify that each departure has an earlier arrival, wait or initial stock.
Add a missed-connection scenario and state who absorbs delay, storage and customer communication. This converts a service description into an auditable operating policy. Compare customer and operator measures on the same horizon.
