Three questions hide inside one word.
The first question is about the article: has this piece of equipment been built and tested against a published minimum performance standard, and does it carry a document saying so. The second is about the installation: is putting it into this particular aircraft an approved change, and who is entitled to approve it. The third, and the one people skip, is whether the function is required at all for the flying you do — because required equipment is held to a standard that optional equipment is not.
A product page can only ever answer the first. Everything else depends on your aircraft, your operating category and the airspace you intend to enter, which is why an honest manufacturer tells you the article status and then sends you to somebody who knows your aeroplane.
The article: an approval for the box.
Aviation authorities publish minimum performance standards for classes of equipment — altimeters, transponders, radios, recorders — and a manufacturer can have a product tested against one. In Europe the resulting authorisation is an ETSO; in the United States the equivalent is a TSO. The two systems recognise each other in many but not all cases, which is a question for your authority rather than for a catalogue.
What such an approval means is narrow and worth stating plainly: this article was built under an approved system and meets a published standard. It does not say the article is suitable for your aircraft, and it does not permit anyone to install it. Individual units are released on a form that accompanies the part, and that form belongs with the aircraft records — not in the box the instrument came in.
Em que caminho está a sua instalação?
Move the equipment slider with the aircraft left on a certified glider and watch the path shift the moment the instrument stops being an extra and starts replacing something the aircraft is required to have. That is the hinge the whole system turns on. Then switch the aircraft to a national or experimental category and the columns collapse — fewer forms, the same physics, and the responsibility moves to you.
The installation: standard, minor, major.
European rules recognise a catalogue of standard changes — pre-approved, well-understood modifications that an authorised maintenance organisation can carry out and record without going near a design organisation. Radio and transponder installations, non-required instruments and traffic systems are the classic entries, subject to conditions the catalogue spells out. If your case fits one, the paperwork is proportionate and everybody involved has done it before.
Outside the catalogue the change is minor and needs approved design data from a design organisation or the authority, or it is major and needs either the type-certificate holder's approval or a supplemental type certificate. The American system draws the same line in different words: minor alterations get a logbook entry, major ones need approved data. The pattern is identical everywhere — the further a change gets from the aircraft as certified, the more design responsibility somebody has to formally accept.
The practical trigger for crossing that line is almost always the same: displacing an instrument the aircraft is required to have. Adding a vario beside the six-pack is one kind of job. Removing the airspeed indicator and putting its information on a screen is a completely different one, no matter how good the screen is.
National categories, experimental, and the builder's freedom.
A great deal of European sport flying happens in aircraft that sit outside the common airworthiness rules and are governed nationally — ultralights and microlights, homebuilts, historic types. There, the equipment rules come from a national association and its inspectors, and they differ from country to country in ways that no general article can usefully summarise. The same is broadly true of American experimental and light sport aircraft, where the operating limitations rather than a type certificate set the boundary.
Freedom in these categories is real but it is not total, and the exception is worth memorising: equipment required by the airspace is required by the airspace. A transponder mandatory zone does not care what your aircraft category is. Neither does a radio requirement. What changes is who signs for the installation, not whether the equipment has to perform.
Reading a product page honestly.
When one of our pages says an instrument is certified, read which document it names. The iris all-in-one carries an EASA STC — an installation approval for a list of glider and motor-glider types — which answers the second question for those types and no others. It still does not mean you may fit it yourself to your aircraft this weekend. When a page makes no such claim, the instrument is intended as non-required equipment and for the national and experimental categories, which is most of the aircraft our customers actually fly.
Neither statement removes a step from the list above. The article status is the one thing a manufacturer genuinely knows about your project, and we would rather write it plainly than let a marketing word do the work of a document.
No seu cockpit.
Paperwork and physics meet in the same place: the panel. What fits, what it draws and what it displaces are worked out in the panel-planning article, and what has to be checked once a year afterwards is in the annual-check article. Between those two, the only genuinely difficult question is the one at the top of this page — and it is best asked before the money is spent, not after the hole is cut.
EASA STC for 360 glider and motor-glider types — the installation approval, already on file for the types it lists.
Installation manual, mass and power figures per unit — the first things the person who signs the release will ask you for.
Non-required equipment in a glider — the row the sorter calls a standard change, and the shortest path on this page.