Comparison

M.E.L.C. vs 737 Tools · Annunciator Lights

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

M.E.L.C.

This tool helps aircraft engineers calculate the expiration dates for airplane defects based on minimum equipment lists. It provides a clear overview of all critical dates and allows for customization of defect categories.

Highlights
  • Calculate defect expiration dates
  • Supports categories A, B, C, D
  • View all important dates at a glance
  • Customize defect categories
Features
Read full description

M.E.L.C. is a tool for the aircraft engineers to calculate the expire date (with Category A, B, C and D) of defected airplanes in accordance with the minimum equipment list. With one quick view all important dates are visible. And a function to customize all categories.

About

737 Tools · Annunciator Lights

Features
Read full description

An annunciator light just came on. The call is yours. 737 Tools is a technical study and reference companion for 737 NG maintenance, built around that moment: understand the system, find the right box, work the fault — in the right order. Data is 737 NG. Many systems, lights and circuit breakers carry over to the 737 Classic and the MAX, so much of it applies there too — always confirm against the approved documentation for your specific aircraft. ANNUNCIATOR LIGHTS Every light by ATA chapter, with the full technical picture: • What triggers it and what clears it • Fault modes — the same light, different causes depending on switch position or configuration, each with its own path • Related circuit breakers, with panel and exact grid position • The LRUs involved • Related MEL items, with a clear NO DISPATCH warning • Your own field notes, saved on the light E/E TOUR — FIND THE COMPUTER Troubleshooting usually ends with a BITE test on a box you first have to find. The E/E Tour is a photographic walkthrough of the electrical/electronic compartment with every LRU marked on real photos of the bays. Tap a marker and you know the shelf and the neighbours before you open the hatch. CB panels are mapped the same way, each breaker pinpointed on the panel image. Pinch to zoom, double-tap to move in, swipe between bays. DAMAGE REPORTS Lightning strike inspections, hail, ground equipment contact — a dozen findings scattered across the airframe and a notebook full of loose photos. Create a report, add each finding with photos, location and measurements, keep them organised as one job, and export it as a PDF or ZIP from the aircraft. Paperwork you close out on the spot. COMMON PN Every line and hangar has its own short list of part numbers. Build your own catalogue: add each PN with photos and notes, organised by zone and category, and export your collection to share it with the team. ON THE RAMP • Fully offline — no signal needed at the stand or in the hangar • One search box across lights, LRUs, circuit breakers and part numbers • No account, no cloud — your notes, reports and PNs stay on your phone • Full backup to a single file, saved wherever you like TRAINING AND REFERENCE ONLY Designed for aircraft systems study and fault simulation. Information may not be current or fleet-specific and does not replace approved AMM, FIM, MEL or any official documentation — always work from the current approved manuals and your operator's procedures. Independent app, not affiliated with, authorised by or endorsed by any aircraft manufacturer.

Screenshots

M.E.L.C.4 screens
737 Tools · Annunciator Lights4 screens

Verdict

The call

The clearest difference is price: M.E.L.C. at Free against 737 Tools · Annunciator Lights's $9.99. M.E.L.C. also leads on iOS requirement (13.0 vs 15.0). 737 Tools · Annunciator Lights's advantage is in-app purchases (none vs 1) and update cadence (every 6 weeks vs every 18 months). On ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

M.E.L.C. is free to download; 737 Tools · Annunciator Lights costs $9.99 up front. M.E.L.C. sells 1 one-off in-app purchase. 737 Tools · Annunciator Lights asks for nothing beyond the download.

UpkeepUpdate frequency

M.E.L.C. ships an update every 18 months, 737 Tools · Annunciator Lights every 6 weeks. The most recent releases landed on November 4, 2026 and November 8, 2026 respectively.

Scorecard4 real differences · 6 level
M.E.L.C. versus 737 Tools · Annunciator Lights: the parameters behind the verdict, then further details
ParameterM.E.L.C.737 Tools · Annunciator Lights
PriceFree — better$9.99
Rating5.0 (1 ratings) — better—
Positive reviews75.0% of reviews—
Number of ratings1 — better—
Update frequencyEvery 18 monthsEvery 6 weeks — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree—
DevicesiPhone, iPod, Apple WatchiPhone, iPad, iPod
Requires iOS13.0 — better15.0
Further details — not scored
Size6 MB60 MB
Age rating4+4+
DeveloperJanko EnkeAdria Raventos ruiz

In-app purchases

1 purchases

M.E.L.C.

One-time1
  • Full version$0.99
None

737 Tools · Annunciator Lights

No in-app purchases

Questions

Is M.E.L.C. free?
M.E.L.C. is free to download, with in-app purchases available.
Is 737 Tools · Annunciator Lights free?
737 Tools · Annunciator Lights costs $9.99, with no in-app purchases.
Do M.E.L.C. or 737 Tools · Annunciator Lights have ads?
Neither M.E.L.C. nor 737 Tools · Annunciator Lights shows ads.
Which is updated more often, M.E.L.C. or 737 Tools · Annunciator Lights?
M.E.L.C. ships an update every 18 months, and 737 Tools · Annunciator Lights every 6 weeks. Most recently, M.E.L.C. was updated on November 4, 2026 and 737 Tools · Annunciator Lights on November 8, 2026.

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