Scenario 2: Union Bidding & Quality of Life Penalties

During the Rostering phase (assigning pairings to named crew members), the optimizer must respect crew preferences and seniority bidding. These are rarely hard constraints; instead, they are "soft constraints" modeled via cost penalties to guide the solver toward crew-friendly schedules.

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📌 The Scenario

Background: The pilot union's Collective Bargaining Agreement (CBA) allows pilots to "bid" (request) specific days off. Because of manpower shortages, the airline cannot guarantee every bid will be honored.

The Requirements:

1. Identify if a duty overlaps with a pilot's requested day off.
2. Apply a massive cost penalty if a senior pilot's bid is denied.
3. Apply a smaller penalty if a junior pilot's bid is denied.
4. Add this to the final Roster cost to force the optimizer to respect seniority.

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💻 The Rave Solution

graph LR
    A[Duty overlaps Day Off?] -->|Yes| B{Check Crew Seniority}
    A -->|No| C[Penalty = 0]
    B -->|High| D[Penalty = 10,000]
    B -->|Low| E[Penalty = 1,000]
    D --> F[Add to Roster Cost]
    E --> F
    C --> F

// ====================================================================
// MODULE: CBA - Seniority Bidding & Day Off Penalties
// ====================================================================

CONSTANTS:
  %senior_bid_penalty% = 10000.0;
  %junior_bid_penalty% = 1000.0;
  %seniority_threshold% = 10; // Years of service
ENDCONSTANTS

// 1. Identify if a duty is scheduled on a requested day off (RDO)
// 'crew.%requested_days_off%' is a keyword array provided by the external system
%violates_rdo% = 
  duty.%start_date% in crew.%requested_days_off%;

// 2. Calculate penalty based on seniority
%rdo_violation_penalty% =
  if %violates_rdo% then
    if crew.%years_of_service% >= %seniority_threshold% then
      %senior_bid_penalty%
    else
      %junior_bid_penalty%
  else
    0.0;

// 3. Aggregate across the Roster
%total_bidding_penalty% = sum(duty(roster), %rdo_violation_penalty%);

// 4. Inject into the objective function
PROPERTY cost OF Roster
  RULE:
    %financial_cost% + %total_bidding_penalty%;
ENDPROPERTY