01 / Occupational profile
Your 15U occupational profile
Rotor, engine, and ground-run noise
Common occupational factor
Running turbine engines for maintenance checks, operating on an active flight line, and performing aircrew duties in flight expose repairers to sustained high-intensity noise.
Hydraulic fluid, fuel, and solvent contact
Common occupational factor
Chinook maintenance involves repeated handling of hydraulic fluid, engine oil, and fuel during component removal, servicing, and leak troubleshooting along the airframe.
Work at height and awkward lifting
Common occupational factor
Daily inspections and component changes require climbing and working on the fuselage exterior, often lifting heavy components (engines, transmissions, gearboxes) with hoists in confined spaces.
Vibration and whole-body loading during flight duties
Assignment-dependent
Crew chiefs and flight engineers experience sustained airframe vibration, hard landings, and sling-load/hoist loads during flight operations.
02 / Your service
What did you actually do?
Your MOS is the starting point. Your actual assignment, era, equipment, location, and duties determine which parts of the occupational history are relevant. Use the Evidence Builder below to select your actual duties and see records that may corroborate them.
15Us remove and install CH-47 subsystem assemblies — engines, transmissions, gearboxes, rotor heads, and mechanical flight controls — then rig and check them against tolerances in technical manuals. Daily and scheduled inspections involve opening every access panel and physically checking grease points, fluid levels, drive shafts, and hydraulic lines along the full length of the airframe, often while working at height on the fuselage. Phase inspections strip the aircraft down for weeks at a time. Many 15Us also serve as crew chiefs and flight engineers, which adds in-flight duties: sling-load operations, hoist work, dust landings, and talking pilots onto pinnacles they cannot see. Shifts commonly run past ten hours, and postflight paperwork and fault documentation follow every mission.
67U was the designator before Army aviation maintenance was reorganized into the current CMF 15 aircraft-specific codes, with CH-47 maintenance becoming 15U. The Chinook airframe and the flight-line work are continuous across the rename; the unit and era served matter more than which code appears on the DD-214.
Duties that may vary by assignment
- Removing, installing, and rigging engines, transmissions, gearboxes, and rotor heads
- Daily and scheduled inspections of the full airframe, often at height
- Phase (periodic) inspections that disassemble major aircraft systems
- Operational checks, troubleshooting, and fault diagnosis
- Crew chief and flight engineer duties, including sling-load and hoist operations
- Dust-landing and field-site maintenance support during flight operations
- Hydraulic fluid and fuel handling during repairs and servicing
- Working on elevated platforms, ladders, and the airframe exterior
Related historical codes: Legacy 67U CH-47 Medium Helicopter Repairer (pre-CMF 15 designator)
Private, on this page only
Military Occupational Evidence Builder
Based on what you actually did in the military, what records might document it? Select only what applied to you. No name, file number, contact details, free text, or upload. Nothing is saved or sent.
Military service
Army · 15U CH-47 Helicopter Repairer
For another specialty, open its guide from the MOS library. A job code alone does not establish individual duties or exposure.
Era(s) of service
Deployments
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Your Evidence Builder identifies records that may document your service history. If VA has already decided your claim, the next question is different: what did VA accept, what did VA reject, and why?
Request a free decision review03 / Corroboration
Building your occupational history
Records matter because they can connect a job title to an individual's actual work and circumstances.
Rotor, engine, and ground-run noise
Records that may corroborate it
- · Hearing-conservation audiograms (DD 2215/2216) and DOEHRS-HC records
- · Flight records (DA Form 759 series) or crew-member orders documenting flight duty
- · Evaluations describing maintenance or aircrew duties
Limit: Documented noise supports the in-service event only. A current hearing disability under 38 CFR § 3.385 or a tinnitus complaint, and a medical link, are still required.
Hydraulic fluid, fuel, and solvent contact
Records that may corroborate it
- · Occupational health or hazmat-program records, if enrolled
- · Evaluations describing maintenance duties
- · Unit safety records for the aviation maintenance company
Limit: The MOS does not establish contact with any specific fluid or exposure level. Era, tasks, a current diagnosis, and a medical opinion all still matter.
Work at height and awkward lifting
Records that may corroborate it
- · Sick call and physical therapy entries during the assignment
- · Line-of-duty or incident reports for a fall or lifting injury
- · Evaluations describing phase-maintenance duties
Limit: Typical aircraft-maintenance demands do not by themselves establish that a specific joint or injury is related to service; a current diagnosis and medical opinion are required.
Vibration and whole-body loading during flight duties
Records that may corroborate it
- · Flight records documenting hours and mission type
- · Line-of-duty reports for in-flight incidents
- · Evaluations describing aircrew duties
Limit: Flight duty alone does not establish a specific musculoskeletal or neurological diagnosis; clinical findings and a medical opinion are required.
04 / Evidence standard
What your MOS can — and cannot — establish
May help document
Work performed, circumstances of service, consistency of an alleged exposure, and the nature or duration of duties where supported by individual records.
Does not automatically establish
A diagnosis, medical causation, severity, percentage, presumption, or entitlement to service connection.
05 / Medical evidence
Conditions that may be relevant to the occupational history
This is not a list of conditions to claim. A veteran's actual diagnosis and individual service record determine relevance; occupational evidence is not medical causation.
Hearing +
Tinnitus and hearing loss
Why the occupation may matter: Turbine engine runs and flight-line noise are sustained features of CH-47 maintenance and aircrew duty.
Records and clinical evidence: Audiometry meeting 38 CFR § 3.385, service audiograms, and a medical opinion.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Spine / joints +
Back, shoulder, and knee conditions
Why the occupation may matter: Lifting heavy aircraft components and working at height in confined spaces load the back and joints repeatedly.
Records and clinical evidence: Current diagnosis, in-service treatment or duty records, and a medical opinion.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Skin +
Skin conditions from hydraulic fluid and fuel contact
Why the occupation may matter: Repeated skin contact with hydraulic fluid and fuel is part of routine maintenance tasks.
Records and clinical evidence: Current dermatology diagnosis, duty records, and a medical opinion.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
Mental health +
PTSD or related conditions from flight incidents
Why the occupation may matter: Crew chiefs and flight engineers may experience hard landings, hoist missions, or in-flight emergencies during deployed operations.
Records and clinical evidence: Current diagnosis, a corroborated stressor, and a medical opinion.
Occupational history alone does not establish this diagnosis or its medical relationship to service.
06 / Exposure record
ILER and toxic exposure
For applicable exposure-related claims, VA may review the Individual Longitudinal Exposure Record (ILER) and a toxic exposure risk activity (TERA) memorandum along with deployment and occupational records. An ILER entry does not automatically establish exposure or service connection.
07 / After a decision
Why a 15U claim may still be denied
An exposure finding is not the same as a grant. These are examples from the researched guide, not predictions about a particular case.
VA may accept
A duty or event consistent with the service record
But may deny
A diagnosis, medical relationship, or rating element
Record to examine
Decision findings, service and private treatment records, examination rationale, and medical opinions.
Noise accepted, hearing link rejected
A normal separation audiogram alone does not decide a hearing claim, but examiners often rely on it without addressing the full flight-line and in-flight noise history.
Back or shoulder condition with no in-service treatment
Repairers often worked through strains to keep the aircraft flying; maintenance logs, evaluations, and buddy statements may help document the duty demands.
Flight-related stressor not independently verified
In-flight incidents may not appear in an individual's records; flight records, unit histories, and crewmember statements may help corroborate them.
Oakridge Claims / Appeals Focused
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The important question is what VA accepted, what it rejected, and why. A decision review considers the decision, examinations, and the complete record — including private and VA records that may need development. Oakridge is appeals-focused — core work is post-decision, but initial and new claims are accepted on a case-by-case basis (no fee for pre-decision work).
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15U questions
Does my 15U or 67U MOS prove I flew on the aircraft?
No. Maintenance duties and aircrew duties are distinct, though many soldiers in this field perform both. Flight records and crewmember orders document actual flight status and hours.
Is 67U the same job as 15U?
Yes — 67U was the designator used before CMF 15 reorganized Army aviation maintenance by airframe. The CH-47 duties described here apply to both eras; note both codes when compiling your records.
What records show the hydraulic fluid or noise I was around?
Unit safety and industrial hygiene records, hearing-conservation audiograms, and evaluations describing your maintenance duties are the usual starting points.
Sources and legal references
General education only; not legal or medical advice. Oakridge Claims is a private business, not affiliated with or endorsed by VA. Nothing here establishes a representative-client relationship or guarantees a result. Free accredited VSO help is available.