Sofema Online (SOL) considers key features related to STC & PMA (or equivalent) across the 4 Major Certification Authorities.
Introduction - Definitions & Core Differences
At a high level, the distinction lies in modification versus replacement.
STC (Supplemental Type Certificate)
An STC is issued when an applicant has received approval to modify an aircraft, engine, or propeller from its original design (Type Certificate).
• Scope: Major design changes (e.g., installing a new Wi-Fi system, changing the interior layout, modifying the avionics suite).
• Nature: It represents a change to the approved type design.
• Global Acceptance: generally well-harmonized via Bilateral Aviation Safety Agreements (BASA) between the four authorities, though "validation" is often required.
PMA (Parts Manufacturer Approval)
PMA is an approval granted (primarily by the FAA) to manufacture replacement parts for aircraft products. It serves as an alternative to the Original Equipment Manufacturer (OEM) parts.
• Scope: Replacement of existing parts (e.g., filters, brake pads, turbine blades, interior latches).
• Nature: It is a manufacturing and design approval combined.
• Two Types of PMA:
The "Big 4" Regulatory View (FAA, EASA, ANAC, TCAA)
While the FAA is the originator and leading proponent of PMA, the other three agencies have nuanced views that affect global interchangeability.
FAA (USA)
• STC: Originator (issues STCs for US-registered aircraft)
• PMA: Champion (issues most PMAs; treats PMA parts as fully airworthy / OEM-equivalent)
EASA (Europe)
• STC: Validator (often validates FAA STCs; also issues its own)
• PMA: Cautious (uses EPA concept; accepts FAA PMA mainly for non-critical parts; stricter on critical items)
TCAA (Canada)
• STC: Harmonized (closely aligned; readily accepts FAA STCs)
• PMA: Accepting (generally accepts FAA PMA via agreements/approval mechanisms)
ANAC (Brazil)
• STC: Harmonized (often follows FAA/EASA lead; relevant for Embraer ecosystem)
• PMA: Accepting (generally accepts FAA PMA; documentation must be precise)
Key Regulatory Challenge: While an FAA PMA part is legal in the US, installing it on an aircraft that might be transferred to an EASA jurisdiction (Europe) can cause paperwork headaches. EASA automatically accepts FAA PMAs only if they are not "Critical Components" or if specific agreement criteria are met.
Detailed Comparison: STC vs. PMA
STC (Supplemental Type Certificate)
• Primary purpose: An STC is used to modify the aircraft design, such as adding functionality or changing configuration.
• Engineering basis: It requires showing the modification complies with airworthiness standards for the change, for example, through structural or electrical analysis.
• Data rights: The STC holder owns the data related to the modification.
• Impact on leasing: It is generally neutral or positive if the modification adds value, but can be negative if the modification becomes outdated or undesirable.
PMA (Parts Manufacturer Approval)
• Primary purpose: A PMA is used to replace an existing aircraft part, usually for maintenance or repair.
• Engineering basis: It requires proving the part is equal to or better than the OEM part, either by identical design or by test and compliance evidence.
• Data rights: The PMA holder owns the manufacturing data for that specific part.
• Impact on leasing: PMA parts have historically been viewed negatively in leasing, particularly when approved by test and computation.
Challenges & Opportunities
• Cost Reduction (PMA): PMA parts are typically 30% to 60% cheaper than OEM parts. For airlines operating older fleets, this is a massive boost to cash flow.
• Availability (PMA & STC): When OEMs stop supporting older aircraft ("sunset" fleets), PMAs and STCs keep the planes flying by providing obsolete parts or modernizing outdated systems.
• Leverage: Even if an airline doesn't buy PMA, the threat of switching to PMA is a powerful negotiation tool to get lower prices from the OEM.
• Cross-Border Transfer: Moving an aircraft from an FAA (US) operator to an EASA (EU) operator is the biggest hurdle. If the aircraft is full of PMA parts, the receiving authority may require validation data that the lessor lacks, forcing the removal of those parts.
• Warranty Voiding: OEMs often threaten that using non-OEM parts (PMA) will void the warranty on the main assembly (e.g., the engine).
Why Leasing Companies Object to PMA
This is the most critical financial friction point in the industry. While airlines (operators) love PMA for the cost savings, Lessors (owners) often prohibit them. Here is why:
Diminution of Asset Value (Residual Value) - Lessors view aircraft as financial assets that must be sold or re-leased eventually.
• The "Pure" Configuration: An aircraft with 100% OEM parts is a "universal donor." It can be leased to any airline in any country.
• The "Mixed" Configuration: An aircraft with PMA parts is limited. Some top-tier airlines (e.g., flag carriers) have internal policies prohibiting the use of non-OEM parts. If a lessor accepts a plane back with PMA parts, they have shrunk their pool of potential next customers.
Traceability and Records
Aviation value is driven by paperwork (Back-to-Birth records).
• OEM parts have a single, unbroken chain of trust.
• PMA parts, especially those generated by "Test and Computation," are viewed by some financiers as "rogue" variables. If the records are slightly messy, the part becomes worthless.
The "Calculated Risk" of Engine PMAs
This is most acute in engines.
• If an engine worth $10M has a set of PMA blades installed, the OEM (e.g., GE, Rolls-Royce, CFM) may refuse to service that engine under their "Total Care" or "Power by the Hour" maintenance agreements.
• Since most lessors rely on these OEM maintenance programs to preserve value, PMA parts can effectively break the maintenance contract, leaving the lessor with a massive liability.
Re-Certification Costs
If a lessor takes back an aircraft with PMA parts and the next lessee refuses them, the lessor must pay to:
• This cost far outweighs the initial savings the previous airline enjoyed. Therefore, lessors simply ban PMA in the lease agreement to avoid this risk.
Summary Table: The Leasing Conflict
Airline
• Motivation: The airline focuses on low operating costs (OPEX).
• View on PMA: It is Pro-PMA because it wants to reduce costs, for example, saving around 40% on brake pads and filters.
Lessor
• Motivation: The lessor prioritizes high residual value and asset liquidity.
• View on PMA: It is Anti-PMA because it fears PMA use could limit the aircraft’s future marketability.
OEM
• Motivation: The OEM seeks to maintain a monopoly on aftermarket sales.
• View on PMA: It is strongly Anti-PMA and actively discourages PMA use in order to protect its revenue streams.
Regulator (FAA)
• Motivation: The regulator focuses on safety and market competition.
• View on PMA: It is Pro-PMA because it considers PMA parts safe and beneficial for a competitive market.
What is EPA (European Part Approval)?
While the FAA issues a specific certificate called a "PMA" to a manufacturer, EASA does not have a standalone certificate called "EPA."
Instead, EPA is a mandatory marking requirement (under EASA Part 21.A.804).
• The Concept: If a company designs and manufactures a part for an aircraft, but that company is not the original Type Certificate (TC) holder (e.g., not Airbus, Boeing, or Safran), they must mark that part with the letters "EPA".
• How it is generated:
In short, FAA PMA is a specific approval you get. EASA EPA is a mark you apply to parts produced under a non-OEM design approval.
EPA vs. PMA: The Comparison
FAA PMA (USA)
• Legal Basis: FAA PMA is a specific approval, granted by license or by Test & Computation, to manufacture replacement parts.
• Identification: The part is identified by being marked “FAA-PMA.”
• Scope: It mainly applies to replacement parts such as filters, blades, and brackets.
• Origin: It was created to allow competition in the US spare parts market.
EASA EPA (Europe)
• Legal Basis: EASA EPA is a marking requirement applied to parts produced under an STC, Minor Change, or ETSO by a non-TC holder.
• Identification: The part is identified by being marked “EPA” together with the Part Number.
• Scope: It can apply to replacement parts or to parts installed as part of a larger modification, such as an STC.
• Origin: It was created to identify non-OEM parts for traceability and maintenance safety.
Global Acceptance of EPA (The "Big 4" View)
The acceptance of EPA parts relies heavily on the Bilateral Aviation Safety Agreements (BASA) between Europe and other nations.
• FAA (USA):
Acceptance: The FAA generally accepts EASA EPA parts for installation on US-registered aircraft under the US-EU BASA.
Condition: The part must be accompanied by an EASA Form 1 (Authorized Release Certificate). The FAA treats these as valid airworthy parts, equivalent to obtaining a US PMA.
• TCAA (Canada):
Acceptance: Canada readily accepts EPA parts. Under the Canada-EU agreement, an EASA Form 1 for a new part is recognized by TCAA without the need for further validation, provided the design data (STC/Minor Change) is also validated or accepted.
• ANAC (Brazil):
Acceptance: Similar to Canada, Brazil accepts EPA parts as part of an approved design change (STC) validated by ANAC.
Summary of Alternates (Hierarchy of Lessor Preference)
If a leasing company bans PMA, what are the acceptable alternatives?
Opportunities for EPA
The biggest opportunity for EPA currently lies in Cabin Interiors.
• Airlines often use local European DOAs (Design Organizations) to refresh interiors (seats, carpets, galleys).
• These parts are marked EPA.
• Because cabin parts are generally "non-critical" and high-wear, lessors are increasingly tolerant of EPA parts in the cabin, provided the DOA is reputable (e.g., Diehl, Recaro) and the paperwork (EASA Form 1) is perfect.
TCAA (Transport Canada Civil Aviation) - Key Equivalent: PDA (Part Design Approval)
In Canada, the term "PMA" is not used for domestic manufacturing. Instead, they separate the design approval from the production approval more distinctly than the FAA.
The PMA Equivalent: PDA (Part Design Approval)
• Definition: A PDA is issued to a Canadian manufacturer to approve the design of a replacement part (similar to the FAA's "PMA design approval").
• Production: To manufacture the part, the PDA holder must also hold a Manufacturer Certificate (MC).
• Marking: Parts are generally marked with the manufacturer's name, part number, and the letters "PDA" or the specific approval number.
The EPA Equivalent: STC Part Marking
• Like EASA, if a part is produced as part of a Canadian STC modification, it doesn't get a separate "PMA" certificate. It is simply an STC part.
• Form: TCCA Form One (Equivalent to FAA 8130-3 or EASA Form 1).
ANAC (Brazil - Agência Nacional de Aviação Civil) - Key Equivalent: CPAA / APAA (Approved Aeronautical Product Certificate)
Brazil follows the FAA's regulatory structure (RBAC 21 is a clone of FAR 21) but uses different terminology for the approval document.
The PMA Equivalent: CPAA (Certificado de Produto Aeronáutico Aprovado)
• Often translated as APAA (Attestation of Approved Aeronautical Product).
• This is the approval granted to a Brazilian manufacturer to produce replacement parts for an aircraft where they are not the Type Certificate holder.
• Legal Basis: RBAC 21.303 (Replacement and Modification Parts). This regulation is virtually identical to the FAA's 14 CFR 21.303, which governs PMA.
The TSO Equivalent: OTP (Ordem Técnica Padrão)
• This is the Brazilian equivalent of a TSO (Technical Standard Order). While TSO/OTP is for "standardized" articles (such as seatbelts or radios), simple replacement parts sometimes fall into this category in Brazil.
• Form: ANAC Form F-100-01 (The Brazilian "8130-3").
Lessor View: Because Embraer is Brazilian, ANAC is highly respected. However, "CPAA"
Summary: The "Big 4" Equivalency Matrix
This table is critical for cross-checking records during a lease return.
FAA (USA)
• Replacement Part Approval: The FAA uses PMA (Parts Manufacturer Approval) for replacement parts.
• Marking on Part: The part is marked “FAA-PMA.”
• Release Document: The authorized release document is Form 8130-3.
• Standard Parts (TSO): Standard parts are approved under TSO.
EASA (Europe)
• Replacement Part Approval: EASA has None as a direct equivalent to PMA and instead relies on STC or Minor Change approval status.
• Marking on Part: The part is marked “EPA” (European Part Approval).
• Release Document: The authorized release document is EASA Form 1.
• Standard Parts (TSO): Standard parts are approved under ETSO.
TCAA (Canada)
• Replacement Part Approval: Canada uses PDA (Part Design Approval) for replacement parts.
• Marking on Part: The part is marked with “PDA” or the STC number.
• Release Document: The authorized release document is TCCA Form One.
• Standard Parts (TSO): Standard parts are approved under CAN-TSO.
ANAC (Brazil)
Replacement Part Approval: Brazil uses CPAA / APAA (Approved Product Cert.).
Marking on Part: The part shows the Manufacturer P/N plus Approval Reference.
Release Document: The authorized release document is ANAC Form F-100-01.
Standard Parts (TSO): Standard parts are approved under OTP.
Special Note on "Reciprocal Acceptance"
While the names differ, the Bilateral Aviation Safety Agreements (BASA) between these four powers create a "Global Acceptance" loop, but with caveats:
Next Steps
Sofema Aviation Services (SAS) and Sofema Online (SOL) Provide Classroom, Webinar & Online training. Please see the websites or email Team@sassofia.com for support.
