English to French Other Tourism & Travel Airline companies

Fare classes definition
To protect seats for consumers who may book at the last minute and would be willing to pay full rate, the revenue manager sets a limit on the number of discount fare units available, thereby establishing fare class inventories. Each segment of price corresponds to a fare class in a limited amount.
Capacity allocation involves determining the share of the capacity that will be available for booking at each price, and setting booking limits for the various price categories/ fare classes that have been included in the differential pricing structure.
Revenue Management obeys to the following principle: 8
- Service firms select customers on the basis of their willingness to pay and their profitability: this  is  the  end  of  the  rule  “first  come,  first  served”:  The most profitable fare class is sold in priority.
There are three types of risks in the capacity allocation for a revenue manager:
- Risk of /////spill/////: Seats are booked too quickly at reduced rates and there is none left, which
compels to decline customers who would have paid the full or higher prices.
- Risk of spoilage: The revenue manager declines the booking at the lower rate because he believes there will be a customer ready to pay the full price, but no one shows up.
There is an empty seat known as spoilage of available capacity.
- Risk of dilution: The revenue manager offers low prices or reductions to increase the
sales  volume  but  the  latter  doesn’t  increase.  There  is  a  loss  of  revenue.

From a tutorial document relating to Revenue Management for an airline Cie
Risk of spoilage = risque de gâchis
Rsik of dilution = risque de dilution

Thanks for you help with reference if possible.