NMX‑LGS‑30 / Rev 00 / aircraft structures & fleet support / strut · rigs · overhaul 2026 · Product Page

NMX-LGS-30 · ENGINEERED TO ORDER — LANDING-GEAR SHOCK ABSORBERS & OLEO STRUTS

One leg carries the landing. Spring, damper, and the truth about sink rate.

Name: Aircraft Landing-Gear Shock Absorber
Brand: Neometrix

A landing drops the aircraft's mass onto its legs at metres per second — megajoules in half a metre of stroke, without a bounce. The oleo-pneumatic strut is aviation's answer: nitrogen is the spring, metered oil is the damper, a tapered pin makes resistance follow the landing, and the load-stroke curve's fatness — 80–90% for a good oleo — decides the peak load the airframe ever feels. The unglamorous half is the gland: seals holding 100+ bar on a sliding chrome leg, because a weeping gland becomes a flat strut and a hard landing. For legacy transport fleets we run the whole programme — engineering characterisation, manufacture, qualification by drop test, and overhaul — with the rigs built in-house, because that is the house trade. The class is engineered to order for fleet-level indigenisation programmes; no delivered landing-gear shock absorber is claimed — the record is stated as it stands.

Enquire — strut programmes Capability sheet (PDF)

Illustrative of the class — a complete aircraft oleo-pneumatic landing-gear shock strut mounted upright on a heavy raw-steel assembly stand with yellow-edged base rails in a working workshop: fresh machine-grey outer cylinder with a clevis head and a small service port, a mirror-polished chrome inner piston partly extended, hinged scissor torque links joining cylinder to piston, tidy workbenches, a tool wall and a parts rack soft-focus behind, clean light floor, no people and no readable markings

Fig · 01 The honest leg — gas above, oil below, chrome in between, and every landing's energy with nowhere else to go

Duty

spring + damperone oleo leg, both jobs

Efficiency

80–90%the load-stroke curve's fatness

Sealing

100+ bar, slidingthe gland is the honesty

Proof

by drop testload-stroke recorded

Status

engineered to orderfleet indigenisation class

ISO 9001 / 14001 Engineered to order Qualification by test Aircraft GSE & test-rig franchise Noida · India

Overview

The article, and everything it takes.

A strut programme is never just a strut. It is metallurgy, sealing, plating, a gas-oil schedule — and the rigs that prove all of it to an airworthiness authority. This page is that whole programme, because half of it is test equipment, and test equipment is the house trade.

Illustrative of the class — a landing-gear drop-test rig in a tall clean test bay: a high fresh-grey steel tower with vertical guide rails, a heavy sliding crosshead carrying a chrome-and-grey shock strut bearing down onto a stack of flat steel mass plates, a massive impact platform beneath on squat cylindrical load cells, a chain hoist at the tower head dropping to the crosshead, fresh yellow safety railing around the base, clean light floor with a yellow line, no people and no readable markings

Fig · 02 The landing, rehearsed — a guided mass, a defined sink rate, and the load-stroke curve that decides everything

One leg, two jobs. Inside the strut, nitrogen rides above oil. The gas is the spring — it stores the landing's energy and carries the aircraft's weight at rest, which is why the servicing chart plots pressure against extension. The oil is the damper: compression drives it through a metering orifice, and a tapered metering pin changes the orifice area through the stroke, so the resistance follows the landing itself — soft at touch, firm in the middle, controlled at the end. On rebound, recoil damping stops the stored energy punching the leg back out.

Efficiency is the whole point. A steel spring gives back everything it takes; an oleo absorbs. The measure is the load-stroke curve — the fatter the rectangle, the more energy swallowed at a lower peak load. A good oleo reaches 80–90%, and every percentage point is structure the airframe never has to carry and fatigue it never has to suffer.

And the gland is the honesty. All of it depends on dynamic seals holding 100+ bar across a sliding, chrome-plated piston, from winter aprons to summer runways. A weeping gland becomes a flat strut; a flat strut turns every landing into a hard one. Seal selection matters — but surface finish and plating quality decide leak life, which is why the manufacturing half of this programme is inseparable from the design half.

The class is engineered to order for fleet-level indigenisation programmes — article, qualification rigs and overhaul as one scope. No delivered landing-gear shock absorber is claimed: the record is stated as it stands.

Complete

Article + rigs + overhaul

The strut, its qualification plant, and the line that keeps it airworthy — one programme, one party.

First-principles

Characterised, not copied

Geometry, metallurgy, sealing, gas-oil schedule — established by engineering, proven by test.

Test-proven

The drop tower decides

Load-stroke recorded at defined sink rates — qualification by measurement, not by resemblance.

Architecture

Characterise, make, drop, keep.

The schematic follows the article and the programme around it — the leg's two jobs, the metered oil, the sealed gas, the drop-tower proof — then characterisation, manufacture, test and the overhaul loop that carries a fleet for decades.

FIG · 03STRUT PROGRAMME ARCHITECTURE · THE ARTICLE / CHARACTERISE + MANUFACTURE / DROP + PRESSURE + ENDURANCE RIGS / OVERHAUL + RECORDS

Fig · 03 Proven by drop, not by resemblance

Arc · 01

The Article

Cylinder, chrome piston, gland, metering pin, torque links, charging valves — a gas spring and an oil damper sharing one machined leg.

Arc · 02

Characterise & Manufacture

Geometry, ultra-high-strength steel, surface treatments, seals, schedule — then forge, machine, grind, plate, inspect.

Arc · 03

The Qualification Plant

Drop tower with recorded load-stroke; proof, leakage, endurance and cold rigs — built in-house, delivered as scope.

Arc · 04

Overhaul & Records

Re-seal, re-plate, NDT, re-qualify — per-serial cards of landings, servicing and pressures for the fleet's life.

Running a fleet whose struts have no source? Send the article's envelope, the fleet size and the airworthiness route — a clause-by-clause compliance matrix within two working days · [email protected]

Send tender spec

Specifications

Reference programmes, built to the fleet.

The parameters below describe reference programmes. Strut envelope, materials route, rig capacities and overhaul depth all follow from three givens: the fleet's articles, the sink-rate and mass cases its airworthiness authority sets, and the service life the operator must reach.

Illustrative of the class — an overhaul bench for landing-gear struts in a clean workshop: a mirror-chrome piston resting on two machined steel V-blocks, a neat row of new black elastomer gland seals and bronze bearing rings on a white tray, a slender tapered steel metering pin on a cloth, a dial bore gauge standing in an open steel cylinder section with its face angled away, machine tools of the shop soft-focus down the aisle, clean laminated bench surface under soft even light, no people and no readable markings

Fig · 04 The unglamorous half — seals, pin, chrome and a bore gauge: where leak life is actually decided

Where strut programmes go wrong

Resemblance instead of characterisation — geometry copied, metallurgy guessed, seals assumed. The gas-oil schedule treated as a detail, when the servicing chart is the strut's personality. Sealing surfaces under-specified — finish and plating decide leak life, not the seal catalogue. No recoil discipline — a leg that returns the landing as a punch. Qualification by installation — flown, not drop-tested. Proof pressure without endurance — one good day, no long life. Cold forgotten — seals and schedules that only work in summer. Overhaul without re-qualification — a rebuilt strut is a new strut until the rig says otherwise. And no per-serial records — a fleet that cannot tell a tired leg from a young one.

So the programme runs the other way. The article is characterised from first principles and substantiated by stress work. Manufacture carries inspection at every stage — forging to final plating. Qualification is by test: the drop tower's recorded load-stroke at the authority's sink rates and attitudes, with proof, leakage, endurance and low-temperature rigs beside it — all built in-house, because rigs are the house trade. Overhaul re-qualifies, never merely reassembles. And every leg carries its record — which is what lets an airworthiness authority sign, and keep signing for decades.

Full specification — expand

System	Aircraft landing-gear shock absorbers & oleo-pneumatic struts — indigenisation programmes with qualification plant, overhaul lines & servicing GSE
Governing Idea	One leg, two jobs — the nitrogen charge is the spring, metered oil is the damper; megajoules absorbed in half a metre of stroke
Metering	Orifice + tapered metering pin vary resistance with stroke; recoil damping controls the rebound
Efficiency	The load-stroke curve's fatness — 80–90% for a good oleo — lower peak loads, lighter structure, longer fatigue life
The Gland	Dynamic seals at 100+ bar on a sliding chrome-plated piston across temperature extremes — finish and plating decide leak life
The Leg's Furniture	Torque links, axle fittings, gas and oil charging valves, and the servicing chart — pressure against extension
Two-Stage Struts	Dual-chamber gas springs — soft over the apron, firm in the flare
Characterisation	From first principles: geometry, ultra-high-strength steel metallurgy, surface treatments, sealing system, gas-oil schedule — substantiated by stress work
Manufacture	Forge, machine, grind, plate — dimensional and NDT inspection at every stage
Qualification	By drop test — defined sink rates, attitudes and masses, load-stroke recorded; plus proof-pressure, leakage, endurance-cycling and low-temperature rigs
The Rigs	Built in-house and delivered as scope — drop tower, pressure, leakage, endurance, cold — the test-rig house's half of the programme
Overhaul	Re-sealing, re-plating, NDT (MPI/FPI) and re-qualification — a rebuilt strut is new only when the rig agrees
Records	Per-serial cards — landings, servicing, pressures — the fleet's memory of every leg
The Split	The site's hydro-gas suspension validation system and damper test benches prove vehicle units; this programme develops the aircraft's own leg — article, rigs and overhaul together. The landing gear test facility is the gear-level sibling — the complete leg exercised as a facility discipline — and the tyre nitrogen charging rig is its servicing kin
Scope Boundary	Ours: engineering characterisation, design & stress substantiation, materials & processes, sealing system, assembly & charging, the qualification plant (drop, proof, leak, endurance, cold), overhaul lines, servicing & charging GSE, documentation, training, spares & AMC — to the customer's specification and airworthiness requirements. Bought-in certified: seals & bearings from qualified makers, charging hardware, instrumentation, NDT consumables. The customer's: the fleet, its airworthiness authority, its acceptance
Status	Engineered to order — fleet-level indigenisation programmes, article by article; no delivered landing-gear shock absorber is claimed

PDF · 1 page

Landing-Gear Shock Absorber — Capability Sheet

Tender Response

Send article envelope, fleet size & airworthiness route — compliance matrix in two working days

Variants

One programme, four fronts.

What changes is where the fleet stands — developing a strut, proving one, keeping one alive, or servicing one on the line.

Var · 01

Development & Manufacture

Indigenisation programmes for legacy fleets — characterisation, substantiation, materials, sealing, assembly and charging.

Var · 02

The Qualification Plant

Drop-test towers and proof, leakage, endurance and cold rigs — for our programmes or the customer's own.

Var · 03

Overhaul & Re-qualification

Strip, re-seal, re-plate, inspect, re-prove — lines and procedures that keep a fleet's legs young.

Var · 04

Servicing GSE & AMC

Charging rigs, servicing tooling, spares and support — the flight-line end of the same discipline.

Applications

Wherever a fleet must keep landing.

The operators who own legacy legs, and the programmes that keep them airworthy.

A · 01Air force transport fleets

A · 02Helicopter & trainer fleets

A · 03Aircraft builders & MROs

A · 04Airworthiness qualification programmes

A · 05Landing-gear component makers

A · 06Special-platform & vehicle struts

FAQ

Common questions.

Plain-language answers from the engineering team.

Q · 01 How does an oleo strut actually absorb a landing?

By making the energy do work it cannot get back. At touchdown the inner piston drives up into the outer cylinder, and two things happen at once. The nitrogen charge compresses — that is the spring, storing energy and setting the static stance (which is why ground crews read strut health as pressure against extension on the servicing chart). And the oil is forced through the metering orifice — that is the damper, converting kinetic energy into heat it can never return. The refinement that makes an oleo an oleo is the tapered metering pin riding through the orifice: as the stroke progresses the pin's diameter changes the open area, so the damping force tracks the landing — gentle at first contact, strongest through the middle where the energy is, controlled at the end so the leg never slams its stop. On rebound the gas pushes back, and recoil damping — a rebound chamber and flap valve — makes the return deliberately slow, because an aircraft that bounces has simply been handed its landing back. The result, done well, is a load-stroke curve that is almost a rectangle: maximum energy at minimum peak load, which is the whole art.

Q · 02 Why is strut efficiency worth so much airframe weight?

Because the strut sets the largest vertical load the structure will ever routinely see. Certification defines landing cases — sink rate, mass, attitude — and the energy of each case is fixed physics: it will be absorbed. The only question is the shape of the force that does it. A plain steel spring absorbs energy along a triangle — force rising linearly with stroke — so its peak force is roughly twice the average it needed. An oleo, metering oil so force rises fast and then holds nearly flat, fills the rectangle: 80–90% efficiency against the spring's ~50%. For the same landing in the same stroke, the oleo's peak load into the airframe is decisively lower — and that peak is what sizes the gear attachments, the wing spar path, the fuselage frames. Every point of strut efficiency is kilograms of structure the aircraft never carries and fatigue cycles its joints never accumulate. This is why strut character is not a maintenance detail but a design quantity — and why a replacement or indigenised strut must reproduce the original's load-stroke behaviour, proven on a drop tower, not merely its envelope and thread sizes.

Q · 03 What makes the sealing system so critical — and so hard?

The gland asks for contradictions. It must hold gas at a hundred-plus bar for months without measurable loss — a static duty asking for maximum squeeze — while letting a chrome leg slide through it on every taxi bump and landing without scoring, stick-slip or flat-spotting — a dynamic duty asking for minimum friction. It does this from high-altitude winter cold, where elastomers stiffen and shrink, to brake-soaked summer aprons; through dust, de-icing fluid and hydraulic oil; for years between overhauls. The engineering answer is a system, not a part: primary seals backed by secondary elements, scraper rings keeping the world out, bearing rings keeping side loads off the seal, and — decisively — the counter-surface: the piston's chrome (or modern HVOF) plating at exactly the right hardness and micro-finish, because a surface polished too smooth starves the seal of its oil film and one too rough machines it away. This is why leak life is decided in the grinding and plating shop as much as in the seal catalogue — and why our programme treats surface engineering, seal selection and the gas-oil schedule as one inseparable package, proven together on the endurance rig with cold-soak cases included.

Q · 04 How does indigenisation work when the original maker is gone?

By treating the article as evidence, not as a template. Engineering characterisation starts from what a fleet actually holds — served articles, worn articles, documents where they exist — and rebuilds the engineering truth from first principles: precise geometry with tolerances chosen from function; materials established by metallurgical analysis (an ultra-high-strength steel identified by composition, hardness, microstructure — then sourced to an equivalent certified specification); surface treatments and platings characterised for thickness and hardness; the sealing system re-engineered with current, obtainable seal technology; and the gas-oil schedule reconstructed from strut geometry and confirmed against the fleet's own servicing charts. Then the substantiation: stress work to the landing cases, materials coupons, process qualifications. And then the honest step that separates engineering from imitation — qualification by test. The new strut must reproduce the load-stroke behaviour on the drop tower at the authority's sink rates, hold proof pressure, pass leakage and endurance and cold. An article that merely resembles the original proves nothing; an article that performs identically under instrumented test is airworthy on its own evidence — which is precisely what an airworthiness authority needs in order to sign.

Q · 05 What does the drop-test rig actually do?

It gives the strut its landing, on the ground, with instruments watching. The rig is a tall guided tower: a carriage carries the strut and calibrated mass plates representing the aircraft's share of weight on that leg; a hoist lifts the assembly to a computed height; release converts height into exactly the sink rate the case demands at impact. The strut lands on a platform mounted on load cells; displacement transducers ride the stroke; accelerometers ride the mass. One drop yields the curves everything turns on: force against stroke (the area is the energy absorbed, the peak is the load the airframe would feel, the shape is the metering's signature), acceleration against time, and rebound behaviour. Cases walk through the authority's table — limit landings, the reserve-energy case, attitudes, tyre-and-wheel combinations where specified. The same tower proves consistency between serials, requalifies overhauled struts, and catches the drift a fleet would otherwise discover on a runway. Beside it stand the quieter rigs — proof pressure, leakage over time, endurance cycling through tens of thousands of strokes, low-temperature soak — because a leg must not merely survive one heroic drop; it must do ordinary landings, forever. Building such rigs is the half of this programme that is simply the house trade.

Q · 06 What do you build, what is bought in — and what is claimed?

Divided honestly. What Neometrix provides: the programme — engineering characterisation and design substantiation; materials and processes (forging, machining, grinding, plating, with inspection at every stage); the sealing system engineering and the gas-oil schedule; assembly and charging; the qualification plant — drop-test tower, proof-pressure, leakage, endurance and low-temperature rigs, built in-house and delivered as part of scope; overhaul lines with NDT and re-qualification; servicing and charging ground support equipment; and documentation, training, spares and AMC — to the customer's specification and airworthiness requirements, which is how fleet indigenisation is invariably tendered. What is bought-in certified: seals and bearings from qualified makers, gas charging hardware, instrumentation and NDT consumables — proprietary items of established makers, integrated rather than imitated. What is the customer's: the fleet, its airworthiness authority, and the acceptance decisions built on the evidence. And the record, stated plainly: no delivered landing-gear shock absorber is claimed, and the class is engineered to order — article by article, around the fleet it must carry.

↗

The suspension & servicing family from Neometrix.

The physics twin on tracks, the bench that proves dampers, and the rig that services the same leg — engineered at our Noida facility.

↗ Suspension

Hydro-Gas Suspension (HSU) Validation System

The same gas-spring, oil-damper physics — proven for tracked vehicles.

↗ Test Benches

Hydraulic Damper Test Bench

Force-velocity truth for dampers — the bench side of the discipline.

↗ Servicing

Aircraft Tyre Nitrogen Charging Rig

The flight-line kin — set-point nitrogen for tyres, struts and accumulators.

Browse all Neometrix product lines.

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and the landing cases.

The projects desk replies within two working days with a clause-by-clause compliance matrix and a budgetary quotation. Write to [email protected] or use the form.

Enquire — strut programmes Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED TO ORDER — LANDING-GEAR SHOCK ABSORBERS & OLEO STRUTS ONE LEG, TWO JOBS · THE GLAND IS THE HONESTY · PROVEN BY DROP ENGINEERED IN NOIDA · INDIA

One leg carries the landing. Spring, damper, and the truth about sink rate.

The article, and everything it takes.

Article + rigs + overhaul

Characterised, not copied

The drop tower decides

Characterise, make, drop, keep.

The Article

Characterise & Manufacture

The Qualification Plant

Overhaul & Records

Reference programmes, built to the fleet.

Where strut programmes go wrong

One programme, four fronts.

Development & Manufacture

The Qualification Plant

Overhaul & Re-qualification

Servicing GSE & AMC

Wherever a fleet must keep landing.

Common questions.

The suspension & servicing family from Neometrix.

Hydro-Gas Suspension (HSU) Validation System

Hydraulic Damper Test Bench

Aircraft Tyre Nitrogen Charging Rig

Send the article
and the landing cases.

Similar Products

Share This Page

One leg carries the landing. Spring, damper, and the truth about sink rate.

The article, and everything it takes.

Article + rigs + overhaul

Characterised, not copied

The drop tower decides

Characterise, make, drop, keep.

The Article

Characterise & Manufacture

The Qualification Plant

Overhaul & Records

Reference programmes, built to the fleet.

Where strut programmes go wrong

One programme, four fronts.

Development & Manufacture

The Qualification Plant

Overhaul & Re-qualification

Servicing GSE & AMC

Wherever a fleet must keep landing.

Common questions.

The suspension & servicing family from Neometrix.

Hydro-Gas Suspension (HSU) Validation System

Hydraulic Damper Test Bench

Aircraft Tyre Nitrogen Charging Rig

Send the articleand the landing cases.

Similar Products

Share This Page

Send the article
and the landing cases.