A question that comes up often from those who operate under RBAC 91 (Brazil's equivalent of FAR Part 91) and are studying a move into air taxi: "the aircraft is the same, shouldn't the maintenance be the same?"
The mechanics are the same. The control regime is not — and the distance between the two is exactly what the migration to 135 (Brazil's equivalent of FAR Part 135) demands. Understanding that distance early is the difference between a smooth certification process and discovering, in the middle of it, that years of records don't support what the new operation requires.
The logic behind the difference
RBAC 91 regulates general aviation: whoever flies is, in general, whoever chose to fly — the owner, their family, their guests. The regulator accepts that part of the risk is managed by the interested party.
RBAC 135 regulates public air transport: the passenger buys a service and has no way to evaluate the aircraft carrying them. The State evaluates on their behalf — and the price of that is a maintenance regime that is stricter, better documented and more audited.
The practical differences derive from that logic:
What changes, in practice
The maintenance program. Under 91, maintenance follows the manufacturer's continuing airworthiness instructions and the general requirements — with room for the operator to manage. Under 135, the aircraft's maintenance program is part of the company's certification process: documented, submitted to ANAC and mandatory as written. The phrase "we've always done it this way" loses all value — what counts is what the approved program says.
Component limits. This is the difference that surprises most: limits that in general aviation can, in certain cases, be managed on condition — the classic example is engine TBO in private operation — become, as a rule, mandatory under the commercial regime, according to the approved program. The "healthy" component that went past the limit is not savings: it is the aircraft out of compliance.
Inspections. Under 91 there is its cycle — in Brazil, with the IAM (Inspeção Anual de Manutenção, the annual maintenance inspection) as the calendar milestone. 135 works on the approved program's cycle, typically denser, and with the expectation that each inspection be traceable and evidenced, not merely "done".
Who can perform it. Commercial operation narrows the field: services are concentrated in certified maintenance organizations, with the formal responsibilities that the relationship requires.
Oversight and reports. Under 135, the operation enters ANAC's continuous radar — audits, follow-up, and reporting obligations that 91 doesn't have, such as the §135.417 report for those it applies to.
Records. The silent difference that swallows the others: under 135, CTM is not good practice — it is a permanent demonstration of compliance. Exact hours and cycles per component, directives with evidence of compliance, a complete trail of every intervention. The level of proof that under 91 shows up at resale, under 135 shows up every week.
The migration trap
Those planning to migrate from 91 to 135 — including via the Operador Simples route, which lowered the barrier to entry — tend to list the obvious challenges: manuals, training, certification. What derails schedules, though, is almost always the historical CTM: years of records in folders and spreadsheets that cannot reconstruct the aircraft's exact state with the precision the new regime requires.
The practical recommendation is a single one: organize technical control as if it were 135 before you need it to be. It costs little in the routine and is worth everything on the day the operation — or the sale of the aircraft, which makes a similar demand — requires the proof.
How Alis handles this
Alis CTM was designed for both regimes — and for the transition between them:
- Hours and cycles fed by the flight: entering the logbook updates airframe, engines and components without retyping — the exact baseline that 135 presupposes;
- Due dates by hour, cycle and calendar with alerts — from TBO to IAM, from the directive to the program item;
- Airworthiness directives monitored and with evidence of compliance attached to the record;
- Complete audit trail: who entered it, when, with what document — the proof format that continuous oversight expects to find.
The same airplane can live under both regimes. The technical control that serves both — traceable, exact, auditable — exists in only one way: built before it is required.
This article is informational and does not replace current regulations. Specific maintenance and technical control requirements vary by aircraft type, approved program and operation — confirm in RBAC 91 and 135 and in the documents applicable to your case.