A0435 Fixed-Wing Air Mileage HCPCS Reimbursement

HCPCS Level II code A0435 designates fixed-wing air mileage billed per statute mile for medical air transport. This code is used when a patient requires transport by fixed-wing aircraft and mileage is the unit of billing. Nationwide, air ambulance billing codes like A0435 matter because they affect access to long-distance medical transfers, emergency and interfacility transport logistics, and significant cost components for payers and patients.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the code’s clinical and operational context, typical settings where the code is used, common payer coverage patterns, and common modifiers associated with air transport billing. The publication outlines typical billing practices and what elements influence reimbursement for fixed-wing mileage charges, including distance and transport necessity.

This summary equips revenue cycle professionals, clinical transport coordinators, and policy analysts with foundational knowledge about A0435, clarifies where it fits within air medical services, and identifies the categories of information available and missing for deeper benchmarking and policy review. Data not available in the input is noted where applicable.

Billing Code Overview

HCPCS Level II code A0435 represents fixed wing air mileage, billed per statute mile. This code is used to report transportation provided by fixed-wing aircraft when mileage is the basis for billing.

Service type: Medical air transport (fixed-wing)
Typical site of service: Air transport via fixed-wing aircraft (interfacility or long-distance patient transport)

Clinical Context

A typical patient scenario involves a regionally critical trauma patient located at a rural hospital following a major motor vehicle collision. The patient has multisystem injuries requiring definitive care at a Level I trauma center located several hundred statute miles away. The sending facility arranges a fixed-wing air ambulance transfer to move the patient rapidly and safely to the receiving center for operative management and higher-level critical care. The clinical workflow includes stabilization at the sending ED or ICU (airway management, hemodynamic support, splinting), activation of aeromedical transport, documentation of medical necessity for fixed-wing transfer, mileage calculation from pickup to drop-off in statute miles, completion of preflight and in-flight patient monitoring by flight crew, and delivery to the receiving trauma team for continuing care.

Coding Specifications

Modifier	Description	When to Use
`1H`	Non-physician medical transport service	Use when a non-physician provider documents and bills the fixed-wing air mileage service.
`22`	Increased procedural services	Use when exceptionally greater service is documented during the transfer (rare for mileage but may apply to associated transport services).

Taxonomy Code	Specialty	Notes
`330600000X`	Emergency Medicine Physician	Emergency physicians often initiate and coordinate aeromedical transfers.
`208D00000X`	General Surgeon	Trauma/acute care surgeons receive and manage transferred patients.
`163W00000X`	Flight Nurse	Flight nurses provide in-flight critical care and documentation for transport billing.
`340600000X`	Critical Care Medicine Physician	Critical care physicians coordinate accepting transfers and ongoing ICU care.
`346B00000X`	Air and Surface Transporter	Specialized transport providers who perform and document fixed-wing air ambulance services.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`S72.001A`	Fracture of unspecified part of right femur, initial encounter for closed fracture	Long-bone fractures in remote settings often necessitate fixed-wing transfer for orthopedic surgical management.
`S06.0X0A`	Concussion without loss of consciousness, initial encounter	Head injuries requiring specialized neurosurgical evaluation or monitoring at a tertiary center may prompt air transport.
`T79.A11A`	Traumatic compartment syndrome of right lower limb, initial encounter	Limb-threatening conditions requiring urgent specialist care at a higher-level facility.
`I21.09`	ST elevation (STEMI) myocardial infarction of other anterior wall	Acute cardiac events in rural hospitals may require rapid transfer for interventional cardiology.
`R65.21`	Severe sepsis with septic shock	Critically ill patients needing higher-level ICU resources and transport by fixed-wing for distance.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`99238`	Hospital discharge day management; 30 minutes or less	May be used by the sending facility when documenting discharge and medical necessity prior to transfer.
`99291`	Critical care, evaluation and management of the critically ill or injured patient; first 30-74 minutes	Used for critical care services provided prior to or during arrangements for fixed-wing transfer.
`31500`	Intubation, endotracheal, emergency procedure	Performed at the sending facility when airway control is required prior to air transport.
`92950`	Cardiopulmonary resuscitation (CPR)	Billed if resuscitative measures occur during stabilization before or during transfer.
`99070`	Supplies and materials (except those normally included with the office visit)	Used for additional supplies documented as part of the transport encounter.

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Summary & Overview

HCPCS A0435: Fixed-Wing Air Mileage, Per Statute Mile