Long before glass cockpits automated fuel management, pressurization, and engine monitoring, a dedicated crew member sat at the systems panel behind the pilots and ran those numbers by hand. That crew member is the flight engineer — sometimes called the second officer — and their role remains codified in federal aviation regulations for air carriers operating certain transport-category aircraft. Understanding what a flight engineer does, when one is legally required, and how the position fits into the broader multi-crew environment is essential knowledge for anyone pursuing Flight Engineer certification or studying air carrier operations under 14 CFR Part 121.
This article walks through the regulatory foundation of the flight engineer position, the specific duties and station responsibilities that define the job, the certification requirements an applicant must meet, and the practical safety rationale that makes the three-pilot cockpit meaningful in high-workload operations.
Regulatory Foundation: When Is a Flight Engineer Required?
The requirement for a flight engineer on air carrier flights stems from 14 CFR Part 121, which governs domestic, flag, and supplemental operations by certificate holders. Specifically, the aircraft type certificate and FAA-approved Airplane Flight Manual determine whether a flight engineer is a required crew member. If the type certificate requires a flight engineer, the air carrier must provide one regardless of automation level or the presence of a flight management system.
Under 14 CFR §121.385, each certificate holder must ensure the cockpit crew is appropriate for the aircraft being operated. Section 121.387 requires a qualified flight engineer at the flight engineer station for the entire flight in two cases: (1) any airplane for which the type certificate requires a flight engineer, and (2) independently, any airplane type certificated before January 2, 1964, that has a maximum certificated takeoff weight of more than 80,000 pounds. For airplanes type certificated after January 1, 1964, whether a flight engineer is required is determined during type certification under 14 CFR § 25.1523. This is not a suggestion — it is a hard legal requirement that ties directly to the aircraft's certification basis. Classic examples of aircraft requiring a flight engineer include the Boeing 707, Douglas DC-8, Boeing 727, and early variants of the Boeing 747 and Lockheed L-1011.
The regulation also addresses who may serve as a flight engineer: the individual must hold a Flight Engineer Certificate with the appropriate aircraft type rating, issued under 14 CFR Part 63. The air carrier must list the flight engineer in its operations specifications and must have trained and checked the individual in accordance with its FAA-approved training program.
How the Flight Engineer Station Works
The flight engineer's primary workspace is a dedicated panel — typically oriented perpendicular or at an angle to the main instrument panel, located immediately behind the captain's or first officer's seat. From this station, the flight engineer has direct access to controls and indicators for aircraft systems that would otherwise overload the two pilots during critical phases of flight.
The systems under the flight engineer's primary management typically include:
- Fuel system: monitoring tank quantities, managing fuel transfer, balancing lateral load, and computing fuel burn against the flight plan to verify adequate reserves.
- Pressurization and air conditioning: setting cabin altitude, monitoring differential pressure limits, controlling pack flow rates, and troubleshooting pressurization abnormalities.
- Electrical system: managing generator outputs, bus configurations, battery states, and load-shedding during abnormal operations.
- Hydraulic system: monitoring fluid quantities and pressures, operating hydraulic pumps, and isolating failed systems per checklists.
- Engine monitoring: cross-checking EGT, EPR or N1, oil quantity, oil pressure, and vibration readings for all engines, and calling deviations to the crew's attention.
- Anti-ice and de-ice systems: activating engine and airframe anti-ice as required, verifying system operation, and coordinating with the captain.
- Performance calculations: computing takeoff data, en route fuel checks, drift-down performance in the event of an engine failure, and approach/landing data.
The flight engineer does not normally manipulate primary flight controls — that responsibility rests with the captain and first officer — but the FE is fully integrated into checklist execution, callouts, and abnormal/emergency procedures. On many older aircraft, the FE operates the fuel panel during engine start, brings generators online, and sequences air conditioning packs, tasks that must be completed in coordination with the pilots on a defined timeline.
Crew Coordination and Command Hierarchy
Within the multi-crew environment, the chain of command is clear. The pilot in command (PIC) — the captain — bears ultimate responsibility for the safe conduct of the flight under 14 CFR §91.3 and the applicable Part 121 provisions. The second in command (SIC) — the first officer — assists the captain and is prepared to assume command. The flight engineer occupies a third, supporting role: expert systems manager and performance analyst.
This hierarchy does not mean the flight engineer is passive. Crew Resource Management (CRM) principles, which are embedded in every air carrier training program, expect the FE to speak up when something is wrong. If the FE detects a fuel imbalance, an abnormal engine indication, or a discrepancy between actual and planned performance, the expectation is an immediate, assertive callout to the captain and first officer. The FAA's Risk Management Handbook (FAA-H-8083-2) emphasizes that effective multi-crew operations depend on all crew members maintaining situational awareness and communicating deviations — the flight engineer is explicitly part of that loop.
During abnormal and emergency checklists, most procedures written for three-crew aircraft assign specific steps to the FE. For example, following an engine fire warning, the FE typically handles the fuel shutoff, fire agent discharge, and system isolation steps while the captain focuses on flying the aircraft and the first officer communicates with ATC. This division of labor is the core safety argument for the three-person crew concept.
Certification Requirements Under 14 CFR Part 63
Flight Engineer Certificates are issued under 14 CFR Part 63, Subpart B. To be eligible, an applicant must:
- Be at least 21 years of age.
- Be able to read, speak, write, and understand English.
- Hold at least a second-class medical certificate issued within the preceding 12 months (§ 63.31).
- Satisfy one of the seven aeronautical-experience routes of § 63.37 — for example a commercial certificate with an instrument rating plus 5 hours of FE flight training; 3 years of diversified aircraft-maintenance experience (including 1 year on multiengine aircraft rated ≥ 800 hp each) plus 5 hours of FE flight training; 200 hours of transport-category PIC/SIC time; 100 hours as a flight engineer; an aeronautical/electrical/mechanical engineering degree plus 6 months of multiengine maintenance; a 2-year FAA-approved maintenance course; or an FAA-approved FE course completed within the prior 90 days.
- Pass the FAA written knowledge test for the appropriate category (turbojet, turboprop, or reciprocating).
- Pass a practical test (oral and flight) in the applicable aircraft type.
Type ratings for the Flight Engineer Certificate are issued for specific aircraft and are reflected on the certificate itself. An applicant who qualifies under the pilot route and holds a commercial pilot certificate with an instrument rating may eventually transition to the right seat as a first officer, and the FE experience often provides valuable familiarity with aircraft systems that supplements cockpit flying duties.
Why the Flight Engineer Position Still Matters
Modern turbofan aircraft designed with two-pilot crews have incorporated extensive automation to absorb the workload once managed by a dedicated third crew member. However, for aircraft whose original type certificate specifies a flight engineer, the regulation does not allow the air carrier to simply remove the position because automation has improved. The requirement follows the type certificate.
Beyond the legal obligation, the three-crew model offers genuine safety redundancy. An additional set of eyes monitoring systems continuously reduces the risk that a developing problem — a slow fuel imbalance, a creeping hydraulic quantity loss, a generator trending toward failure — goes unnoticed until it becomes critical. In high-altitude, over-water, or ETOPS-adjacent operations on affected aircraft, that redundancy is particularly valuable.
Air carriers must ensure their flight engineers are current under the recency requirements of Part 121, including proficiency checks, recurrent training on abnormal and emergency procedures, and line-oriented flight training (LOFT) or similar scenario-based assessments. These requirements mirror what is demanded of captains and first officers and reflect the FAA's position that the FE is a full, qualified member of the operating crew.
Key Numbers and Rules
- 21 years old: minimum age for a Flight Engineer Certificate (14 CFR §63.31).
- § 63.31 / § 63.35 / § 63.37: eligibility (age 21, second-class medical within 12 months) / knowledge test / aeronautical experience, respectively.
- § 63.37 is a seven-route reg — satisfy any one: e.g. 200 hrs transport-category PIC/SIC, 100 hrs as an FE, or 3 yrs diversified maintenance (1 yr on multiengine ≥ 800 hp).
- No 1,500-hour requirement — that is ATP experience under § 61.159, a separate certificate.
- §121.387: requires an FE whenever the type certificate requires one, and independently for pre-Jan-2-1964 airplanes over 80,000 lb MTOW.
- §121.385: the general provision governing required cockpit crew composition for air carrier operations.
- Part 63, Subpart B: governs all Flight Engineer Certificate issuance, including written tests, practical tests, and type rating requirements.
Common Test Traps
- Confusing Part 63 with Part 61: Flight Engineer Certificates are issued under Part 63, not Part 61 (which covers pilots). Examiners frequently test whether candidates know the correct regulatory part.
- Assuming automation eliminates the requirement: If the aircraft type certificate calls for a flight engineer, no amount of added automation removes the Part 121 legal requirement to carry one.
- Overlooking the age requirement: Unlike the commercial pilot certificate (18 years) or ATP (23 years for unrestricted), the FE minimum age is 21 — a number easily confused on written tests.
- Misidentifying command authority: The flight engineer is not a pilot in command or second in command in the legal sense. The PIC is the captain; the SIC is the first officer. The FE's authority is systems management, not aircraft command.
- Forgetting the mechanic route: Many students assume a pilot certificate is always required for FE certification. The maintenance route (§ 63.37: 3 years of diversified aircraft and engine maintenance — including 1 year on multiengine aircraft with engines rated ≥ 800 hp each — plus 5 hours of FE flight training) is a valid alternative path.