Part 135 drug and alcohol testing: what 49 CFR Part 40 and 14 CFR Part 120 require

Drug and alcohol testing is not optional for Part 135 operators — it is a federal program requirement enforced by DOT and the FAA, with civil penalties, certificate action, and criminal referrals as consequences for non-compliance. The program must be in place before the first revenue flight and maintained continuously for as long as the certificate is active.

The regulatory framework has two layers: 49 CFR Part 40 (DOT procedural requirements — how testing is conducted) and 14 CFR Part 120 (FAA safety-sensitive employee requirements — who is tested and when). A Part 135 operator is responsible for complying with both.

Who is a covered employee

Under Part 120, drug and alcohol testing applies to employees who perform "safety-sensitive functions" for a Part 135 certificate holder. Safety-sensitive functions include:

• Flight crewmember duties (flight crew performing Part 135 operations)
• Flight instruction duties (instructors giving flight training for the certificate holder)
• Aircraft dispatch duties
• Aircraft maintenance or preventive maintenance
• Ground security coordinator duties
• Aviation screening duties (where applicable)

The key phrase is "perform safety-sensitive functions" — not "are employed in a safety-sensitive position." A part-time pilot who only flies Part 91 for the same employer but occasionally flies Part 135 is covered when performing Part 135 duties. An independent contractor performing maintenance on certificate aircraft is covered. The program covers the function, not the employment relationship.

Owner-operators who are the sole employee and fly only their own aircraft may qualify for certain single-employee exceptions — but this is narrow and requires FSDO confirmation. The safer default is to assume coverage and confirm any exception in writing.

The five testing occasions

Part 120 requires testing in five circumstances:

1. Pre-employment

A covered employee must test negative before first performing a safety-sensitive function for the certificate holder. This includes new hires, transfers from non-safety-sensitive positions, and return from a leave of absence where the employee was not in the random testing pool. A negative pre-employment test is required before the first flight — not within 30 days of the first flight.

2. Random

All covered employees must be in a random testing pool. The FAA sets the minimum annual random testing rates by substance:

• Drug testing: 25% of the average number of covered employees per year (subject to change by FAA notice)
• Alcohol testing: 10% of the average number of covered employees per year

Random means truly random — each employee has an equal probability of selection in each random draw, regardless of prior selections. Testing cannot be weighted toward new employees, employees the employer is concerned about, or any non-random basis. The selection must be made by a scientifically valid random number generator tied to a roster.

Small operators (fewer than ~50 covered employees) typically satisfy the random testing requirement through a consortium/third-party administrator (C/TPA) that pools employees from multiple operators. This is the practical approach — self-administering a statistically valid random program with 3-5 employees is mathematically difficult.

3. Post-accident

Following an aviation accident as defined in 49 CFR Part 830, drug and alcohol testing is required for surviving crew members as soon as practicable. The employer must test as soon as possible but within specific windows: alcohol testing within 2 hours (8 hours maximum); drug testing within 32 hours. Testing cannot be delayed for interviews, paperwork, or administrative convenience.

If testing is not completed within the required window, the employer must document why — not completing the test within the window does not automatically mean no violation, but it does require explanation.

4. Reasonable suspicion

A covered employee may be required to test when a trained supervisor observes specific, contemporaneous, articulable observations of the employee's appearance, behavior, speech, or body odors that are consistent with drug use or alcohol misuse. "Reasonable suspicion" is not a vague feeling — it must be documented in writing by a trained observer as soon as practicable after the determination.

Supervisors and designated employer representatives who may order reasonable-suspicion testing must complete at least 60 minutes of training on the physical, behavioral, speech, and performance indicators of probable drug use, and 60 minutes of training on the same indicators for alcohol misuse.

5. Return-to-duty and follow-up

An employee who violated the drug and alcohol testing rules — refused to test, tested positive, or admitted to use — must complete a substance abuse professional (SAP) evaluation, comply with the recommended treatment, and test negative before returning to safety-sensitive duty. Follow-up testing continues for at least 12 months (and up to 60 months) after return, at unannounced intervals, in addition to random testing.

Substances tested

The DOT drug panel tests for five substance categories:

• Marijuana (THC metabolites)
• Cocaine metabolites
• Opiates (codeine, morphine, heroin metabolite)
• Amphetamines (amphetamine, methamphetamine, MDMA)
• Phencyclidine (PCP)

Expanded panels for other substances are not required by DOT and are not appropriate for federally mandated testing. Alcohol testing measures blood alcohol concentration (BAC) — 0.04 or greater is a violation; 0.02-0.039 requires removal from safety-sensitive duty until the next shift.

What a violation triggers

A positive drug test, confirmed alcohol test at 0.04+, or refusal to test results in:

• Immediate removal from safety-sensitive duties — no grace period
• Referral to a DOT-qualified Substance Abuse Professional (SAP)
• The violation is reported to the DOT Drug and Alcohol Testing Management Information System (MIS) and is reportable on the employee's record
• For pilots: the FAA is notified and the airman certificate is at risk — positive drug tests are reported to the Civil Aviation Registry and can result in certificate action under 14 CFR Part 67 (medical) and Part 61

The certificate holder who permitted a positive-testing employee to continue performing safety-sensitive functions — or who failed to maintain the required testing program — faces separate enforcement action, up to certificate suspension.

Program administration requirements

The certificate holder must:

• Designate a Designated Employer Representative (DER) responsible for program administration
• Have a written drug and alcohol testing policy distributed to all covered employees
• Maintain records per 49 CFR Part 40 Subpart P — drug records for 5 years (positive results), 2 years (negative results and random pool); alcohol records for 5 years (violations) and 1 year (all other)
• Submit an annual MIS report to the FAA for each calendar year the certificate is active
• Use only DOT-certified laboratories and certified breath alcohol technicians (BATs) and screening test technicians (STTs)

Most small Part 135 operators use a C/TPA (consortium/third-party administrator) to manage program administration, random draw logistics, MIS reporting, and collection site coordination. The DER remains a required role — the C/TPA assists, but the certificate holder retains legal responsibility.