NMX‑FDT‑30 / Rev 00 / aircraft systems & depot test / loops · detectors · amplifiers 2026 · Product Page

NMX-FDT-30 · ENGINEERED TO ORDER — FIRE & OVERHEAT DETECTION SYSTEM TEST RIGS

The one system that must never lie. In either direction.

Name: Aircraft Fire & Overheat Detection System Test Rig
Brand: Neometrix

A false alarm aborts a takeoff, grounds the aircraft, discharges bottles into a healthy engine bay. A missed fire loses the aircraft. So the test equipment behind a fire-warning system must prove both directions: the loop that alarms at its threshold — and stays silent everywhere else. The rig's heart is calibrated heat, because heat is the only honest stimulus for a sensing element: alarm temperature, reset and response time read against real degrees and a real clock, any point along the loop; beside it, the signature metrology (resistance, capacitance, insulation — the fingerprints of moisture and chafing) and the amplifier console that injects the faults no flying system can safely rehearse. Equipment of this class has been quoted against a fleet-level air force requirement for fire-detection-system test jigs; no delivered fire-detection test rig is claimed — the class is engineered to order.

Enquire — detection test rigs Capability sheet (PDF)

Illustrative of the class — a fire-detection-system test rig in a clean avionics laboratory: a long steel bench console in fresh machine-grey paint carrying a horizontal tubular calibrated furnace with its clamshell lid ajar and a thin metal sensing element passing through its white ceramic bore, cradle spools of coiled thin stainless sensing element beside it, a vertical patch panel of circular military-style connectors with neatly laced dark looms, a small control pedestal angled away, clean light floor with a yellow line, no people and no readable markings

Fig · 01 The bench that asks both questions — will it alarm at temperature, and will it stay quiet everywhere else

Stimulus

calibrated heatreal degrees, ramped & logged

Verdict

alarm at thresholdtemperature + time, recorded

Both ways

quiet provenfault ≠ fire, margins held

Coverage

element to lamploop · spot · amplifier · indication

Status

engineered to orderfleet-level test-jig class

ISO 9001 / 14001 Engineered to order Depot-level test equipment Fire test franchise Noida · India

Overview

Alarm at the threshold, silence everywhere else.

Around every engine bay and APU zone runs a system whose whole job is a single honest sentence at the worst possible moment. Its test equipment must prove that sentence true in both directions — and prove it again at every depot cycle, for the life of the fleet.

Illustrative of the class — close view of an open split tube furnace on a laboratory bench: two white ceramic half-shells hinged apart with a very thin metal sensing element clamped straight along the axis on small bright machined guides, two fine thermocouple wires laid beside the element, polished clamp fittings at both ends, a small instrument box behind with its face turned away, fresh grey paint and white ceramic under soft even light, no people and no readable markings

Fig · 02 The honest stimulus — a stated length of element, a stated temperature, a stated ramp, and a thermocouple that answers to a calibrator

Three articles, one verdict. The continuous-loop sensing elements routed around hot zones — the averaging type whose resistance and capacitance drift with zone temperature, and the discrete type whose eutectic salt switches sharply at its alarm temperature. The spot detectors — thermal switches guarding known hot points. And the control amplifier with its indication chain — the unit that reads the loop, decides fault or fire, and lights the cockpit. The rig tests all three, because the fleet certifies the system, not a component.

Heat is the only honest stimulus for the element. Electrical simulation exercises the amplifier — not the sensor. So the rig's heart is calibrated heat: tube and split furnaces and temperature baths that bring a stated length of element to a stated temperature at a stated ramp, traceable thermocouples alongside. Alarm temperature, clear temperature, response time are read against real degrees and a real clock — and because a loop must alarm for heat anywhere along its length, elements are surveyed at multiple stations along the run, not blessed at one.

And every alarm test carries its inverse. The quiet margins — no alarm at the temperatures the zone must survive. The discrimination — a chafed short flagged as a fault, never a fire. The signatures — resistance and capacitance against temperature, insulation resistance, continuity — because in-service false alarms are usually moisture and chafing, and the rig's job is to find them on the bench before the fleet finds them on a runway.

Equipment of this class has been quoted against a fleet-level air force requirement for fire-detection-system test jigs. No delivered fire-detection test rig is claimed: the class is engineered to order, and the record is stated as it stands.

Honest

Real degrees, real clock

Thresholds and response times proven with calibrated heat — not inferred from an electrical stand-in.

Two-sided

Alarm and quiet, both proven

Every threshold test paired with its inverse — fault discrimination and quiet margins on the same certificate.

Fleet-grade

Element to cockpit lamp

Loops, spot detectors, amplifiers and indication — the whole chain certified, serial by serial, cycle by cycle.

Architecture

Heat, clock, discriminate, certify.

The schematic follows the question — the element heated honestly, the alarm clocked, the quiet proven, the certificate written — and the machine underneath: heat stations, loop metrology, the amplifier console, and the fixtures and records that make bench numbers mean something on an airframe.

FIG · 03DETECTION TEST RIG ARCHITECTURE · HEAT STATIONS / LOOP METROLOGY / AMPLIFIER + INDICATION / FIXTURES + RECORDS

Fig · 03 Both directions proven — alarm, and quiet

Arc · 01

Heat Stations

Tube and split furnaces, temperature baths, multi-point survey — stated lengths at stated temperatures and ramps, traceably calibrated.

Arc · 02

Loop Metrology

Resistance and capacitance vs temperature, insulation, continuity — the signatures of ageing, moisture and chafing, measured not guessed.

Arc · 03

Amplifier & Indication

Signature simulation, fault injection, dual-loop voting, built-in test — and the lamp, bell and master warning proven to answer.

Arc · 04

Fixtures & Records

Installed routing replicated; per-serial certificates with curves, times and values — the fleet's recertification trail.

Equipping a depot — or replacing legacy test jigs? Send the system types, the element schedule and the test cards — a clause-by-clause compliance matrix within two working days · [email protected]

Send tender spec

Specifications

Reference rigs, built to the test cards.

The parameters below describe reference rigs. Station count, furnace bores and ranges, channel counts and fixture sets all follow from three givens: the system types the depot supports, the element schedule, and the test cards its airworthiness programme runs.

Illustrative of the class — an avionics test station in a clean laboratory: a rack panel in fresh light-grey paint carrying rows of circular military-style connectors with dark laced looms dressed into cable combs, several small brass thermal-switch detectors seated in bright machined aluminium test blocks on the bench, a compact test box with its face angled away, a neat coil of thin sensing element on a stand, cool overhead laboratory light, no people and no readable markings

Fig · 04 The other half of the truth — connectors, looms, spot detectors and the amplifier's fault-injection bench

Where detection testing goes wrong

Only the amplifier tested — an electrical spoof exercises the logic while the element never feels heat. Single-point heat on an averaging loop — local desensitisation missed because the run was never surveyed. An uncontrolled ramp — thermal overshoot reads the threshold early or late. No reset check — an alarm that never clears, discovered airborne. Insulation resistance skipped — the moisture path to false alarms left unmeasured. A fixture that heats the clamp, not the element — the verdict belonging to the tooling. Furnace calibration assumed — thresholds judged against a rig whose own degrees drift. No fault-vs-fire test — the chafed short that reads as an engine fire. And certificates that say “OK” — no curves, no times, nothing to defend when the fleet asks questions.

So the discipline runs the other way. The element is heated honestly — stated length, stated temperature, stated ramp, traceable degrees — and surveyed along the run. Thresholds come with reset and hysteresis; alarms come with quiet margins; signatures come as curves, not single values. The amplifier faces injected faults the flying system can never safely rehearse, and the indication chain answers all the way to the lamp. Furnaces answer to calibrators, reference elements run on schedule, and every article leaves with its numbers on a per-serial certificate — which is what a recertification programme can sign, and defend.

Full specification — expand

System	Aircraft fire & overheat detection system test rig — heat stations, loop metrology, amplifier & indication consoles, fixtures, records
Governing Idea	The one system that must never lie — a false alarm grounds the aircraft; a missed fire loses it; both directions proven
The Articles	Continuous-loop elements (averaging R-C and discrete eutectic types) · spot detectors (thermal switches) · control amplifiers + indication
The Stimulus	Calibrated heat — tube & split furnaces and baths; stated length, stated temperature, stated ramp; traceable thermocouples alongside
Thresholds & Time	Alarm temperature, clear temperature, response time against a real clock — reset and hysteresis proven, not assumed
Any-Point Survey	A loop must alarm anywhere along its length — multi-station survey along the run, ends to middle
The Quiet Side	Fault-vs-fire discrimination — open, short and chafe signatures flagged as faults; quiet margins held at survivable temperatures
Loop Signatures	R & C vs temperature curves, insulation resistance, continuity — the moisture-and-chafing fingerprints behind most in-service false alarms
Amplifier Console	Programmable signature simulation, fault injection, dual-loop voting, built-in test, indication drive to lamp, bell and master warning
Fixtures	Installed routing lengths, clamps and connectors replicated — bench numbers that transfer to the airframe; fleet harness interfaces on the panel
Calibration	Furnace zones & ramps traceably calibrated; reference elements on schedule; the rig's own uncertainty stated
The Record	Per-serial certificates — thresholds, times, curves, insulation values — the recertification trail for the life of the fleet
The Split	The hangar fire test facility proves a building's systems at full scale; this rig proves the aircraft's own warning system on the bench. The fire resistance test rig asks a third question — whether structures endure the standard fire
Scope Boundary	Ours: heat stations with traceable calibration, element handling & multi-station survey fixtures, loop metrology, amplifier consoles with signature simulation & fault injection, indication verification, connector & harness panels, software, records, installation, commissioning, documentation, training, spares & AMC — including build to the customer's specification and test schedules. Bought-in certified: furnace & bath cores, precision LCR & insulation instruments, thermocouples & calibrators, DAQ. The customer's: the detection systems under test and their acceptance schedules
Status	Engineered to order — equipment of this class quoted against a fleet-level air force requirement for fire-detection-system test jigs; no delivered fire-detection test rig is claimed

PDF · 1 page

Fire & Overheat Detection System Test Rig — Capability Sheet

Tender Response

Send system types, element schedule & test cards — compliance matrix in two working days

Variants

One discipline, four stations.

What changes is the article on the bench — a loop, a switch, an amplifier — and whether the depot is equipping new or replacing the jigs a legacy fleet has outgrown.

Var · 01

Loop-Element Test Stations

Calibrated furnaces and baths with multi-point survey fixtures — thresholds, response times and R-C curves for averaging and eutectic elements.

Var · 02

Spot-Detector & Switch Rigs

Threshold and response-time proof for thermal switches — seat fixtures, controlled heat, reset verified unit by unit.

Var · 03

Amplifier & Indication Consoles

Signature simulation, fault injection, voting and BIT — the system-level station from loop connector to cockpit lamp.

Var · 04

Fleet Re-equipment & AMC

Replacement of legacy test jigs — the quoted class — plus fixtures, calibration regimes, training, spares and support.

Applications

Wherever the warning must be true.

The depots that certify, and the fleets that fly on the answer.

A · 01Air force depot-level overhaul

A · 02Aircraft & helicopter builders

A · 03Engine-bay & APU fire-warning systems

A · 04Avionics repair laboratories

A · 05Airworthiness recertification programmes

A · 06Legacy-fleet test-equipment replacement

FAQ

Common questions.

Plain-language answers from the engineering team.

Q · 01 Why is a fire-warning system so hard to test honestly?

Because it has two ways to fail and they pull the test in opposite directions. Make the system more sensitive and you close the missed-fire direction while opening the false-alarm one; make it more discriminating and you do the reverse. The airworthiness answer is that both directions carry numbers: an alarm threshold with a tolerance, a response time with a limit, and equally binding quiet requirements — temperatures the zone runs at every day where the system must not speak, and fault conditions (an open loop, a chafed short) it must report as faults, never as fires. Honest testing therefore has to measure both sides with the same seriousness. A rig that only proves the alarm fires at temperature has done half the job — the easy half. The harder half is proving the silence: quiet margins held below the threshold, discrimination logic that refuses to be fooled by the electrical signature of damage, and reset behaviour that releases the alarm when the heat is gone. That is why the certificate this rig writes carries curves and margins rather than a single tick — the fleet is not asking “did it beep”; it is asking “will it tell the truth, in either direction, at 30,000 feet”.

Q · 02 How does a continuous-loop sensing element actually work?

It is a thermometer disguised as a wire. A thin element — a centre conductor inside a slim tube, separated by a temperature-sensitive filling — is routed around the zone it guards, clipped along cowlings and cases, so that anywhere heat appears, some length of element feels it. Two families dominate. The averaging type uses a filling whose electrical behaviour changes smoothly with temperature: as the zone warms, the loop's resistance falls and its capacitance changes, and the amplifier watches those values against alarm curves — the element integrates heat along its length, which is what makes multi-point testing essential, because a short hot length and a long warm length can present similar numbers. The discrete (eutectic) type uses a salt filling that stays a good insulator until a sharp melting temperature, at which point its resistance collapses abruptly — a crisp, almost digital alarm at a designed temperature, self-restoring as it cools. Both are beautifully simple and both age in the same ways: moisture creeping past seals, chafing thinning insulation, connectors corroding — which is why the rig measures the loop's signature curves, not just its alarm point, and why real heat at stations along the run is the only stimulus that proves the element rather than the amplifier's opinion of it.

Q · 03 What exactly does the rig measure, station by station?

Four stations, one file. The heat station brings a stated length of element — or a spot detector in its seat fixture — to a stated temperature at a stated ramp inside a calibrated tube or split furnace, and records alarm temperature, clear temperature and response time against traceable thermocouples and a real clock; for continuous loops the test repeats at stations along the run, ends to middle, because the specification says any point. The metrology station takes the element's electrical portrait: resistance and capacitance against temperature as curves, insulation resistance at test voltage, continuity and connector integrity — the numbers that drift years before a failure and explain false alarms afterwards. The amplifier console speaks to the control unit in its own language: programmable simulation of loop signatures walks the logic through alarm, clear, open, short and chafe cases; dual-loop voting (AND and OR philosophies), built-in-test behaviour and inhibit logic are exercised; and fault injection proves the discrimination no one can safely rehearse on a flying aircraft. The indication chain is then driven end to end — lamp, bell, master warning — because a perfect detection that never reaches the cockpit is a failure with extra steps. Everything lands in the per-serial record: curves, thresholds, times, values, verdicts.

Q · 04 Why is calibrated heat such a point of doctrine — isn’t electrical simulation enough?

Electrical simulation is essential — and structurally incapable of testing the sensor. When a test set injects the electrical signature of a fire into the amplifier, it proves the amplifier: the logic, the thresholds in its electronics, the indication drive. The element — the part that actually lives in the fire zone, ages in it, and is the usual seat of trouble — never participates. Its filling may have absorbed moisture; its alarm point may have drifted; a pinched length behind a clamp may have gone locally dead. Only real temperature asks the element the service question, and asking it honestly takes engineering: a furnace whose stated temperature is traceable to calibration, a controlled ramp (overshoot reads a threshold early; a crawl reads it late), a stated heated length (averaging elements answer differently to short-hot and long-warm), fixtures that heat the element rather than the clamp, and reference elements run on schedule so the rig's own drift is caught before it grades the fleet's. That pairing — heat for the element, simulation for the amplifier — is the whole architecture of the rig, and the reason the certificate can carry the word “system” honestly.

Q · 05 How does this relate to your other fire pages — the resistance rig and the hangar facility?

Three questions, three machines — the fire franchise in full. The fire resistance test rig asks whether a structure endures fire: furnaces driving a standard time-temperature curve at bulkheads and doors, the pass being integrity when the clock runs out. The hangar fire test facility asks whether a building's systems fight fire: full-scale trays and scenarios in a chamber big enough to behave like a hangar bay, where suppression — and yes, a facility's detection and alarm response — is evaluated at true scale. This page asks the third question: whether the aircraft's own warning system tells the truth — and it is a bench discipline, not a burn: no flames, no trays, just calibrated heat, metrology and logic, applied to flight hardware at depot level. The articles differ (a building's installation versus an airframe's loops and amplifiers), the scale differs (a chamber versus a furnace bore), and the customer differs (an infrastructure programme versus a fleet's recertification cycle). What the three share is the house habit: state the question precisely, stimulate honestly, record everything. Resist it, fight it, detect it — one franchise, three verdicts.

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

Divided honestly. What Neometrix provides: the rig — heat stations (tube and split furnaces, temperature baths) with their traceable calibration regime and reference-element schedule; element handling and multi-station survey fixtures that replicate installed routing, clamps and connectors; the loop metrology (R-C curves, insulation, continuity); the amplifier and indication consoles with programmable signature simulation, fault injection, voting and BIT exercise; the harness interface panels; the software and its per-serial records; and installation, commissioning, documentation, training, spares and AMC — including build to the customer's own specification and test cards, which is how fleet-level test-equipment requirements are invariably tendered. What is bought-in certified: furnace and bath cores, precision LCR and insulation-resistance instruments, thermocouples and their calibrators, DAQ hardware — proprietary instruments of established makers, integrated rather than imitated. What is the customer's: the detection systems under test and the acceptance schedules they must meet. And the record, stated plainly: equipment of this class has been quoted against a fleet-level air force requirement for fire-detection-system test jigs. No delivered fire-detection test rig is claimed; the class is engineered to order, station by station, around the systems a depot actually supports.

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Get a quotation

Send the test cards
and the element schedule.

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 — detection test rigs Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED TO ORDER — FIRE & OVERHEAT DETECTION SYSTEM TEST RIGS HEAT IS THE HONEST STIMULUS · ANY POINT, BOTH DIRECTIONS · CERTIFIED TO THE LAMP ENGINEERED IN NOIDA · INDIA

The one system that must never lie. In either direction.

Alarm at the threshold, silence everywhere else.

Real degrees, real clock

Alarm and quiet, both proven

Element to cockpit lamp

Heat, clock, discriminate, certify.

Heat Stations

Loop Metrology

Amplifier & Indication

Fixtures & Records

Reference rigs, built to the test cards.

Where detection testing goes wrong

One discipline, four stations.

Loop-Element Test Stations

Spot-Detector & Switch Rigs

Amplifier & Indication Consoles

Fleet Re-equipment & AMC

Wherever the warning must be true.

Common questions.

The fire & protection family from Neometrix.

Hangar Fire Test Facility

Fire Resistance Test Rig

Circuit Breaker & Relay Test Bench

Send the test cards
and the element schedule.

Similar Products

Share This Page

The one system that must never lie. In either direction.

Alarm at the threshold, silence everywhere else.

Real degrees, real clock

Alarm and quiet, both proven

Element to cockpit lamp

Heat, clock, discriminate, certify.

Heat Stations

Loop Metrology

Amplifier & Indication

Fixtures & Records

Reference rigs, built to the test cards.

Where detection testing goes wrong

One discipline, four stations.

Loop-Element Test Stations

Spot-Detector & Switch Rigs

Amplifier & Indication Consoles

Fleet Re-equipment & AMC

Wherever the warning must be true.

Common questions.

The fire & protection family from Neometrix.

Hangar Fire Test Facility

Fire Resistance Test Rig

Circuit Breaker & Relay Test Bench

Send the test cardsand the element schedule.

Similar Products

Share This Page

Send the test cards
and the element schedule.