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LSEAT Aerospace
PATENTED INNOVATION — DESIGNED TO EASA CS-25 & FAA FAR-25

Upgrade Economy Comfort Without Sacrificing Seat Density.

Ultra-lightweight (< 1,650 g / 3 seats) non-electric retrofit kit enabling 40° sleep mode. Zero AOG time, installed in < 15 minutes per seat.

Request the EASA Form 1 Dossier View the Kinematic Data Sheet

Download 2025 Technical Brochure

  • EASA Part 21J
  • FAA Part 21
  • 3 moving sub-parts
  • 0 motors

Integrated Kit Mass

< 1,650 g

For a 3-seat block. TSO tolerance < 5 kg on 2 seat track legs.

MRO Retrofit Time

< 15 min

Direct installation without removing seat track legs.

Aircraft On Ground

0 h

Zero forced airframe downtime.

Dynamic Crash Test

16G CS-25 / FAR-25

Automatic spring-return holds an unoccupied seat upright.

Patented coupled motion

Kinematics Data Sheet

Dual composite frame system: the upper frame slides forwards and downwards, with synchronised vertical back-cushion motion. The transmission is purely mechanical: no electric motor, only 3 moving sub-parts, 16G CS-25.562 retention maintained in all four positions.

Kinematic Recline Demonstration

An LSEAT publication showing the coupled glide transmission in motion, from the upright sitting position to the 40° sleep recline. It demonstrates how the mechanism travels; it is not a certification artefact, and the four-position data sheet below remains the authoritative record of the published values.

Plays muted when it comes into view. Unmute with the player controls.

LSEAT passenger positions with backrest recline angle and seat pan travel
Passenger position Backrest
recline 		Seat pan
travel
16G Upright Sitting Mode 0° 0 mm
IFE Watching Mode 12° 45 mm
Relax Reading Mode 25° 30 mm
Sleep Mode (40° Recline) 40° 20 mm

Transmission

Dual composite frame system: the upper frame slides forwards and downwards, with synchronised vertical back-cushion motion.

Architecture

3 moving sub-parts · 0 electric motors · 0 W

Crash retention

16G CS-25.562 retention maintained in all four positions

Rear envelope (Sleep Mode)

0 intrusion on rear seat pitch

Power draw

0 W · no electrical component, no wiring

Seat pan travel is the forward translation of the seat pan from the upright sitting position. All values on this sheet are LSEAT manufacturer engineering data, released with the EASA Form 1 documentation on request.

Certification dossier

Technical Specifications & EASA Form 1

Every figure below is covered by the EASA Part 21J engineering package: engineered architecture, Part 21G subcontracted production, mass margins and compliance with the CS-25.562 / FAR-25.562 cabin safety requirements. The full dossier is released on request.

Backrest geometry, seat pan travel and the four certified positions are set out in the Kinematics Data Sheet. The certification figures that depend on those positions are tabulated below.

Applicable references

  • STC supplied with the kit
  • EASA Part 21J
  • FAA Part 21
  • EASA CS-25.562
  • FAR-25.562
  • TSO-C127
  • 16G Dynamic Crash Test

LSEAT is supplied with an STC (Supplemental Type Certificate), the Part 21J engineering work and a FORM 1. Those are documents LSEAT supplies and releases on request: no STC number is published on this site, and nothing here states that a regulator has already issued an STC for this kit.

Contractual LSEAT technical specifications and associated normative references
Category Parameter Value Normative reference
DELIVERABLES Certification release EASA Form 1 + Part 21J engineering work LSEAT published technical data — lseat.eu/compliances, archived 20 July 2025 (web.archive.org/web/20250720023516/)
DELIVERABLES STC document STC (Supplemental Type Certificate) supplied and released by LSEAT LSEAT published technical data — lseat.eu/compliances, archived 20 July 2025 (web.archive.org/web/20250720023516/)
DELIVERABLES Kinematic architecture 2 composite frames inserted under the original seat pan LSEAT patent
PRODUCTION Manufacturing Certified subcontract production LSEAT published technical data — lseat.eu/compliances, archived 20 July 2025 (web.archive.org/web/20250720023516/)
PRODUCTION Moving sub-parts 3 (no motor, no electronics) Part 21J dossier
MASS Integrated kit mass (3-seat block) < 1,650 g LSEAT published technical data — lseat.eu/compliances, archived 20 July 2025 (web.archive.org/web/20250720023516/)
MASS Load on seat track legs < 5 kg / 2 legs LSEAT published technical data — lseat.eu/compliances, archived 20 July 2025 (web.archive.org/web/20250720023516/)
MASS Kit profile height (above seat cushion) < 0.5 in (12.7 mm) LSEAT published technical data — lseat.eu/compliances, archived 20 July 2025 (web.archive.org/web/20250720023516/)
MAINTENANCE MRO installation time < 15 min / seat, without removing seat track legs LSEAT published technical data — lseat.eu/compliances, archived 20 July 2025 (web.archive.org/web/20250720023516/)
MAINTENANCE Direct maintenance cost reduction -75 % LSEAT manufacturer data
MAINTENANCE Electrical components 0 LSEAT manufacturer data
CERTIFICATION Dynamic crash test 16G CS-25 / FAR-25 LSEAT published technical data — lseat.eu/compliances, archived 20 July 2025 (web.archive.org/web/20250720023516/)
CERTIFICATION Unoccupied seat return Spring-return to upright LSEAT published technical data — lseat.eu/compliances, archived 20 July 2025 (web.archive.org/web/20250720023516/)
CERTIFICATION Aircraft On Ground 0 h MRO procedure

Swipe the table sideways: the category column stays pinned.

Figures are LSEAT manufacturer engineering data, released with the EASA Form 1 documentation on request. Items marked as published technical data are taken from LSEAT's own published compliance page (lseat.eu/compliances, archived 20 July 2025). The LSEAT 2025 brochure is a marketing publication and is not a technical datasheet. Archived copy: web.archive.org/web/20250720023516/

The low profile is what preserves the seat TSO spatial envelope: the kit stands less than 0.5 in (12.7 mm) high above the seat cushion, which is what keeps it within the tolerances of the seat TSO, with no seat or cabin modification.

Download the 2025 Brochure (PDF, 1.5 MB)

Marketing overview of the retrofit kit, published for fleet operators and MRO buyers. The Part 21J engineering dossier, the EASA Form 1 and the certification figures listed above are released on request to qualified operators, MROs and certification authorities.

Download the Inflight Magazine Feature (PDF, 149 KB)

LSEAT product feature as published in Inflight Magazine, recovered from the archived lseat.eu publication. Trade press, not a technical datasheet: it carries no specification figure and is cited for corporate background only.

Restored records

Mechanism Drawing & Cabin Record

Photographs and the mechanism drawing recovered from the archived lseat.eu CDN publication. Every frame on this page was inspected before publication.

  • Two side-view line drawings of the LSEAT seat mechanism, views 4c and 4d, with the seat pan travel dimension and the recline angle callouts marked.
    Drawing · side views 4c / 4d

    Coupled glide mechanism

    Side view 4c / 4d, with the seat pan travel dimension and the recline angle callouts.

  • Economy cabin with an LSEAT seat in full sleep recline, seat-back inflight entertainment screen in the foreground.
    Installed retrofit · 40° sleep recline, IFE serviceable

    Sleep mode, 40° recline

    Full recline in a single-seat block, IFE serviceable in the same position.

  • Reclined LSEAT economy seats beside the cabin window, seat-back screens visible.
    Installed retrofit · intermediate recline, IFE in passenger view

    Relax reading mode

    Intermediate recline with the IFE in clear view of the seated passenger.

  • Installed LSEAT seats in an economy cabin row with two passengers seated.
    Installed retrofit · in situ, no seat-track leg removed

    Installed cabin block

    Retrofit in situ: no seat track legs removed, no cabin sidewall modification.

  • LSEAT economy seats in the relax position with passengers seated upright.
    Installed retrofit · spring return to sitting position

    Relax position in service

    Spring return holds an unoccupied seat in the upright sitting position.

  • A pair of upright LSEAT economy seats with seat-back inflight entertainment screens and armrests.
    Installed retrofit · upright, seat pitch unchanged

    Upright sitting mode

    Seat density unchanged: the kit occupies no additional pitch.

  • LSEAT economy cabin in service, a passenger working on a laptop at a reclined seat beside the window.
    Installed retrofit · passive mechanism, 0 W

    Cabin in service

    Day cabin operation: the mechanism is passive and adds no electrical load.

  • Seat cushion assembly with black anti-slip strips on the seat pan, photographed on the cabin floor.
    Kit component · cushion replaced, seat structure untouched

    Seat cushion assembly

    Kit component: the cushion is removed and replaced, the seat structure is untouched.

Archival imagery published by LSEAT on its previous platform. Cabins and seats shown are LSEAT installations; the drawing is the published mechanism view. No image on this page is presented as a certification artefact.

Company publication

Interview Footage & Field Record

An interview recorded by LSEAT at the Dubai Air Show, published on the company's own channel and embedded here. Playback is entirely on demand.

LSEAT published interview · Dubai Air Show

This interview was recorded by LSEAT at the Dubai Air Show and published on the company's own channel. It is presented here as a company publication: the footage, the audio and the on-screen graphics are LSEAT's own. Nothing recorded in this interview constitutes an LSEAT specification, certification claim or engineering commitment. The engineering values published elsewhere on this site remain the authoritative figures.

Engineering Enquiry

Engineering Contact Hub

Direct line to the LSEAT Aerospace engineering team. Every enquiry is handled by an engineer, not by an automated form: technical response within 24 h, complete documentation on explicit request.

What you receive

Items issued on request, according to the maturity level of your programme.

  • EASA Form 1 Certificate of conformity, released on request after a full review of the certification file.
  • Part 21J Engineering Package Design definition, drawings, bills of material and preventive maintenance instructions.
  • Dynamic 16G Certification Notes CS-25.562 / FAR-25.562 substantiation, Y and Z axes, DMSO 9G / OY 4G seats.
  • MRO Installation Procedure Installation sequence, tooling, labour time and post-installation inspection.
  • Quoted Fleet Pricing Cost per seat, per aircraft, with batch scheduling and volume assumptions.

Direct contact

No generic form: you talk to the LSEAT Aerospace engineering team. Technical response within 24 h.

CS-25.562 FAR-25.562 Part 21J 0 W < 15 min / seat

Company / MRO / OEM address required.

Drawings, Part 21J files or specifications can be sent in reply to your e-mail. No file attachment is accepted by this form.

Privacy & GDPR

* Required fields — Technical response within 24 h