can you please help me?

Amanda is a hearing-impaired repairperson currently employed with the Southwestern Telephone Co. Her job requires her to drive the company truck to remote rural areas in all kinds of weather, to climb telephone poles, to make general repairs to telephone lines, and so on. She has held this position for five years, a full year longer than any employee, and she is quite competent. Amanda recently applied for a promotion to the position of repair crew coordinator, a position that would require her to be in constant communication with all repairpersons in the field. Southwestern rejected Amanda's application, stating that the company "needs someone in this critical position who can speak and hear clearly, someone who does not suffer from any hearing disability." Amanda could perform the job if Southwestern would provide her with a sign interpreter, but Southwestern says it would be too expensive. Should Southwestern be required to accommodate her disability under the ADA? Why or why not?