Is a carrier liable to its passengers for damages caused by mechanical defects of equipments or appliances installed in the carrier?

Yes, whenever it appears that the defect would have been discovered by the carrier if it had exercised the degree of care which under the circumstances was incumbent upon it, with regard to inspection and application of the necessary tests. The manufacturer is considered as being in law the agent or servant of the carrier, as far as regards the work of constructing the appliance. The good repute of the manufacturer will not relieve the carrier from liability. The rationale of the carrier's liability is the fact that the passenger has neither choice nor control over the carrier in the selection and use of the equipment and appliances in use by the carrier. Having no privity whatever with the manufacturer or vendor of the defective equipment, the passenger has no remedy against him, while the carrier usually has. It is but logical, therefore, that the carrier, while not in insurer of the safety of his passengers, should nevertheless be held to answer for the flaws of his equipment if such flaws were at all discoverable. (Necesito v. Paras, G.R. No. L-10605, June 30, 1958)