Escape Routes for Depressurisation and Driftdown


Category: Flight Operations / Performance
Title: Escape Routes for Depressurisation and Driftdown
Date of Issue: March 2026
Applicability: CAT Operators

Background

Escape routing for depressurisation and driftdown scenarios is not explicitly mandated as a standalone requirement.

However, operators are required under EASA Air Operations to ensure the safe conduct of flights, including in abnormal and emergency situations.

For CAT operations, CAT.POL.A.215 En-route – one-engine-inoperative (OEI) requires that, in the event of an engine failure, the aircraft must be able to:

  • maintain adequate terrain and obstacle clearance, and
  • continue the flight to a suitable aerodrome.

In operations involving mountainous terrain or constrained airspace, this effectively requires a clear understanding of how a safe descent or drift-down can be achieved.

Impact on Operators

In a depressurisation or engine-out scenario, crews must react immediately.
The available options are often constrained by:

  • terrain and obstacle environment,
  • aircraft performance limitations,
  • and airspace structure.

Generic manufacturer procedures alone are not sufficient in these scenarios.
Without predefined routing or a clear escape concept, there is an increased risk of:

  • delayed or suboptimal decision-making,
  • loss of situational awareness in high-workload conditions,
  • or non-compliance with terrain and obstacle clearance requirements.

TRS Recommendation

Operators should assess whether escape routing for depressurisation and driftdown:

  • is defined for relevant routes and operational areas,
  • reflects aircraft-specific performance limitations,
  • considers terrain and airspace constraints,
  • and is usable in a time-critical scenario.

TRS Aviation Consulting offers the development of tailored escape routes for depressurisation and driftdown scenarios, based on aircraft performance and operational environment.

Further details:
https://www.trs-aviation.com/services/decompression/

Official Source

EASA Air Operations – CAT.POL.A.215 En-route – one-engine-inoperative (OEI)

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NAT Doc 007 V.2026-1 – What Will Actually Change for NAT Flights

Category: ICAO / NAT Operations
Title: NAT Doc 007 V.2026-1 – What Will Actually Change for NAT Flights
Date of Issue: December 2025
Applicable from: March, 19th 2026
Applicability: CAT & NCC Operators conducting NAT / NAT HLA operations

Why this matters

This update does not change the NAT concept. However, it tightens how NAT procedures are expected to be applied in practice, particularly at the Shanwick and Reykjavik interfaces, during clearance delivery, and in cockpit verification.

The points below focus on where day-to-day NAT operations will actually be affected.

RCL timing is reinforced

Revised wording around Revised Clearances (RCL) reinforces that late changes are not assumed to be acceptable, particularly in Shanwick-controlled airspace.

Operational implications:

  • RCL requests are time-critical and may be rejected if submitted late.
  • Tactical reroutes close to 30°W are less tolerated.

What to review:

  • Dispatcher RCL cut-off times.
  • Crew understanding of the last acceptable point for RCLs.

Ref: NAT Doc 007 Chapter 6

ETA to ETO – small wording, real consequences

The document aligns NAT procedures with ICAO use of Estimated Time Over (ETO).

Operational implications:

  • RCL validity and slot protection are time-based.
  • Inconsistent ETA versus ETO usage can result in clearance mismatch.

What to review:

  • Flight planning system conventions.
  • Dispatcher and crew phraseology alignment.

Ref: NAT Doc 007 Chapters 2 and 6

Reykjavik handling of mismatched clearances

Updated guidance clarifies expectations when clearances do not align with filed or expected routing.

Operational implications:

  • Clearances must be challenged early if routing or timing does not match expectations.
  • Late resolution increases operational risk.

What to review:

  • Crew guidance on clearance verification.
  • Dispatcher escalation paths.

Ref: NAT Doc 007 Chapter 6

FMS waypoint verification is explicitly reinforced

The revised text reinforces explicit FMS waypoint verification, particularly for OTS entry points, coordinate waypoints and random routes.

Operational implications:

  • Waypoint loading errors remain a primary NAT risk.
  • Verification is an operator responsibility.

What to review:

  • NAT cockpit procedures.
  • Cross-check methodology and training emphasis.

Ref: NAT Doc 007 Chapter 8

Shanwick and Reykjavik assume operator-managed error detection

The document reinforces that ATC does not validate route correctness. Incorrect waypoints, timings or degraded navigation remain the operator’s responsibility.

Operational implications:

  • GNSS issues prior to NAT entry require active management.
  • Post-event follow-up and investigation are expected.

What to review:

  • Dispatcher post-flight checks.
  • Internal event reporting and follow-up processes.

Ref: NAT Doc 007 Chapters 8 and 11

What operators should do now

  • Re-brief dispatchers and crews on RCL timing expectations.
  • Align ETA and ETO usage across dispatch, ATC and cockpit procedures.
  • Review FMS waypoint verification procedures.
  • Check OM wording for Shanwick and Reykjavik interface handling.

Official Source

ICAO NAT Doc 007 – North Atlantic Operations and Airspace Manual Edition V.2026-1, Amendment 0 Applicable from 19 March 2026

Further Information

TRS Aviation Consulting supports CAT and NCC operators with NAT procedure reviews and operations manual alignment.

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EASA CS-MMEL Updates

Category: EASA Regulatory Update
Title: EASA CS-MMEL Updates
Date of Issue: December 2025
Applicability: CAT and NCC Fixed-Wing Operators

Summary of Change

EASA has published targeted MMEL/MEL updates (CS-MMEL Issue 4 and CS-GEN-MMEL Issue 3).
This update provides a concise overview of the MEL items that require review.

CS-GEN-MMEL Issue 3 and CS-MMEL Issue 4 – What Has Changed

EASA has published CS-MMEL Issue 4 and CS-GEN-MMEL Issue 3 (ED Decision 2025/021/R).
The MMEL philosophy remains unchanged. The impact is limited to specific items and ATA chapters.

Relevant technical changes are as follows (by ATA chapter):

ATA 23 – Communications

  • HF COM: amendments are only relevant in conjunction with SATCOM installations.
    Clarification of relief logic where HF and SATCOM are considered together as part of the long-range communications concept.

ATA 25 – Equipment / Furnishings

  • Storage bins and compartments: clarified relief conditions, including securing inoperative bins, placarding (“DO NOT USE”), restrictions on storage of loose items, and required crew procedures. For overhead bins without partitions, the entire bin is considered inoperative.
  • Cargo restraint systems: clarified relief where restraint equipment is missing or inoperative, provided approved cargo loading limits are observed or the compartment remains empty.
  • First-aid kits – additional equipment: additional equipment may be inoperative, incomplete or missing. Required additional equipment may be incomplete for flights to a destination where replacement is possible, limited to a maximum of two calendar days. The definition of “additional equipment” is explicitly linked to the Air Operations Regulation.

ATA 31 – Indicating / Recording Systems

  • New MEL item introduced: Usage Monitoring System (UMS).

ATA 32 – Landing Gear

  • New MEL item introduced: Tyre Pressure Monitoring System (TPMS).

ATA 34 – Navigation / Surveillance

  • ACAS: clarified MEL relief logic for degraded modes.
  • New MEL item introduced:  Runway Overrun Awareness and Alerting System (ROAAS)
  • Navigation systems (ADF): clarification regarding inoperative systems installed in excess of those required for the intended route.
  • Enhanced Surveillance (DAPs):
    • Operations in the Single European Sky: time-limited relief (maximum three consecutive calendar days).
    • Operations outside the Single European Sky: relief permitted when compatible with applicable airspace requirements.
  • ADS-B OUT:
    • Operations in the Single European Sky: time-limited relief (maximum three consecutive calendar days).
    • Operations outside the Single European Sky: relief permitted when compatible with applicable airspace requirements.

Operational relevance:
The MEL now explicitly distinguishes between SES and non-SES operations. MEL application must reflect the airspace actually operated.

ATA 35 – Oxygen

  • Minor clarifications to existing MMEL relief conditions.

Affected Manuals

– MEL

TRS Recommendation

– Review MELs against CS-MMEL Issue 4 or CS-GEN-MMEL Issue 3 (as applicable), limited to the ATA chapters listed above and prepare changes for next MEL revision.

Official Source

– EASA CS-MMEL Issue 4 – Change Information (ED Decision 2025/021/R) – EASA Information Security (Part-IS)

– EASA CS-GEN-MMEL Issue 3 – Change Information (ED Decision 2025/021/R)

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EASA Part-IS – ORO Amendment 29 & SPA Amendment 17 – Mandatory Changes for 2026

Category: EASA Regulation – Information Security & Operational Requirements
Title: EASA Part-IS – ORO Amendment 29 & SPA Amendment 17 – Mandatory Changes for 2026
Date of Issue: December 2025
Applicability: NCC & CAT Fixed-Wing Operators, Operators with PBN/RNP, RVSM and ETOPS Approvals

Summary of Change

EASA has released three regulatory packages that materially change how operators must manage digital systems and operational data:

  1. Part-IS (Information Security) – introduces a mandatory Information Security Management System (ISMS), including risk assessment, incident reporting, supplier oversight and a new Information Security Management Manual (ISMM).
  2. AMC/GM to Part-ORO — Issue 2 / Amendment 29 – aligns SMS and ISMS requirements and strengthens expectations for digital-process oversight within OM-A, OM-B and OM-D.
  3. AMC/GM to Part-SPA — Issue 1 / Amendment 17 – updates data-integrity requirements for PBN/RNP/RNP AR, RVSM and ETOPS operations, with emphasis on digital navigation and performance data workflows.

All changes originate directly from the newly published AMC/GM documents, including the Information Security – December 2025 package (ED Decisions 2025/013/R, 014/R, 015/R).

Impact on Operators

The new requirements shift operational oversight from “systems used” to “data relied upon”. Any digital process influencing operational decisions must now be assessed, validated and documented.

Key operator impacts include:

  • ISMS becomes a mandatory core system, not an add-on to SMS.
  • Digital systems must undergo structured risk assessment.
  • NAV-data chains, performance data, EFB workflows and OCC tools must be demonstrably controlled.
  • Supplier oversight becomes a regulatory obligation; cloud-based systems included.
  • SPA approvals (PBN/RNP/RNP AR, RVSM, ETOPS) now depend on documented data-integrity controls.
  • Manuals must reflect updated responsibilities, data flows and competence requirements.

Authorities will review ISMS integration and digital-data governance during 2026 audits.

Affected Manuals

OM-A: Management system, ISMS responsibilities, data-flow descriptions, integration with SMS.
OM-B: Navigation-data processes, performance and W&B workflows, configuration control, SPA-related digital dependencies.
OM-D: Training & competence requirements linked to information security.
ISMM (new mandatory manual): Required under IS.I.OR.250; defines all ISMS processes, controls and responsibilities.

TRS Recommendation

  1. Start ISMS implementation immediately – policy, scope, digital-system mapping.
  2. Conduct an ISAP-based risk assessment – required by the AMC/GM.
  3. Update OM-A/B/D + ISMM as a single, consistent package.
  4. Validate NAV-data and performance workflows – required for SPA compliance.
  5. Establish supplier-oversight mechanisms – contracts, service documentation, verification steps.
  6. Prepare audit evidence early – authorities will expect complete documentation in 2026.

TRS provides a structured ISMM Template, aligned with the AMC/GM requirements, to accelerate implementation.

Official Source

Further Information

For operators requiring support with ISMS implementation, manual revisions, or compliance, TRS Aviation Consulting provides dedicated assistance.

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Holdover Time Guidelines – Winter 2025–2026

Category: FAA Regulation – Operational Safety
Title: Holdover Time (HOT) Guidelines 2025–2026
Date of Issue: 12 August 2025
Applicability: CAT & NCC Operators, Ground De/Anti-Icing Personnel

Summary of Change

Winter is around the corner — and with it comes the challenge of safe ground de/anti-icing operations.
On 12 August 2025, the FAA released the updated Holdover Time (HOT) Guidelines for the 2025–2026 season. These guidelines remain the industry’s key reference for determining safe de/anti-icing holdover and allowance times. This year’s edition introduces six new fluid-specific tables, revised generic values, new precipitation categories, and updated allowance times, along with several editorial clarifications.

Impact on Operators

  • New fluid-specific HOT tables have been added for six fluids: ESSPO Nordwing PG2 (Type II), AFLRUS Green Flo Type IV, AllClear Clear IV Flight, ESSPO Nordwing PG4, Newave FCY-EGIV PLUS, and Xinjiang Clearice-IV. These must be incorporated into operational procedures and ground staff references.
  • Extended cold weather testing (< –14 °C) now provides fluid-specific HOTs for three existing fluids (COREICEPHOB Type II, PROFLIGHT EG4, PROFLIGHT PG4), ensuring safer planning in very cold snow conditions.
  • Removed dilutions: The 75/25 and 50/50 dilutions for Newave FCY-2 (Type II) are no longer valid and should be deleted from manuals.
  • Generic adjustments:
    • Type II generics: several HOT values increased following removal of fluid data.
    • Type IV generics: several HOT values decreased due to inclusion of new fluids with shorter times.
  • Precipitation category expansion:
    • Type I (aluminum & composite): HOT values for Snow mixed with Freezing Fog increased.
    • A new column for Moderate Snow mixed with Rain has been added across all Type I–IV fluid-specific tables.
  • Allowance time changes:
    • Validation table for Type III & IV fluids updated.
    • Increases for Moderate Ice Pellets mixed with Moderate Snow.
    • Additional references for ice pellets mixed with drizzle/freezing drizzle.
    • Clarified guidance for small hail in METAR reports.
  • Editorial clarifications throughout tables (temperature references, note structures) for better operational clarity.

Affected Manuals

  • Operations Manual – HOT references and de/anti-icing procedures.
  • Ground Ops Manual – Integration of new fluid-specific tables, allowance time validations, and staff briefings.

TRS Recommendation

Operators should:

  • Review and integrate the updated FAA HOT Guidelines before winter operations commence.
  • Remove outdated dilution references and adjust procedures for revised HOT values.
  • Update all relevant manuals, checklists, and training materials.
  • Train both flight and ground personnel on new fluid-specific data, cold-weather updates, and expanded precipitation categories.

TRS supports clients in:

  • Updating manuals and documentation in line with FAA HOT 2025–2026.
  • Ensuring compliance through readiness checks before the season begins.

Official Reference

FAA Holdover Time Guidelines – Winter 2025–2026

Further Information

Download FAA HOT Guidelines – Winter 2025–2026 (PDF)
Visit FAA’s Aircraft Ground Deicing Resources

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EASA Part-IS – Upcoming Mandatory Information Security Requirements for Air Operators

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Lost Communication & Emergency Descent Procedures · Part-SERA Update

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EASA SIB 2025-03: Lithium Battery Risks

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EASA SIB 2025-04: Use of Protective Breathing Equipment

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