Collecting registrations: how loggers work and how to log a complete fleet

To many people, an Airbus A320 is simply an A320. To a logger, it is one of many aircraft with an identity of its own – and the decisive question is: Do I already have exactly this registration? Collecting registrations is one of the oldest forms of plane spotting. Here you learn how loggers work, which data really belongs in the logbook, how to log a fleet completely step by step and where even experienced collectors stumble.

What loggers actually collect

A logger notes every aircraft they see by its registration – that is, the marking on the outside of the fuselage, such as D-AIxx on a German aircraft or EI-xxx on an Irish one. How these sequences of letters and numbers are built is explained in the guide Understanding aircraft registrations. The goal is not the most beautiful picture but the most complete list possible: Which aircraft of an airline have you seen? How many examples of a type? Which airframes are you still missing?

Within the scene there are different focuses. Some collect every registration an aircraft carries over its lifetime. Others – often called “frame spotters” – are interested in the individual airframe and count it only once, no matter under how many registrations it flies. Still others concentrate on one airline, one type or their home airport. Where the differences between loggers, photographers and videographers lie is described in the article Loggers, photographers, videographers.

From the underlined book to the database

The principle is old. Long before there were apps, spotters kept printed fleet books and underlined or ticked off every aircraft they had seen. When a new edition appeared, the tedious transfer started from scratch. With spreadsheets and later online databases, logging went digital – since then lists can be matched, sorted and analyzed automatically. The advantages and disadvantages of paper, spreadsheet and app today are compared in the piece Notebook, spreadsheet or app.

Your collecting rule: what counts as a sighting?

Before you write the first line, you should define what a valid sighting is. It sounds banal but decides the meaningfulness of your whole collection. Typical questions:

• Read or photographed? Is it enough to have recognized the registration reliably, or do you need your own photo as proof?
• Seen yourself or only heard? Reading a registration off the live map while the aircraft passes at ten kilometers’ altitude is not a sighting in the classic sense. Many loggers count flyovers only if they actually saw the registration.
• Also from the airplane window? Aircraft you see as a passenger at the gate or while taxiing are counted by some, not by others.
• Partial sightings too? A half-hidden registration that you reconstruct from type and departure time is a gray area. A separate field for the certainty of the entry is worthwhile here.

There is no right or wrong rule. All that matters is that you apply it consistently. If you count generously today and strictly tomorrow, you can no longer compare your numbers later.

The logbook: which fields you really need

A good logbook entry answers the question “Which aircraft, when, where, how do I know?” From that come the core fields:

Field	Example	Why it matters
Registration	D-AINx	unique key of the collection – always write it in the same format
Type	Airbus A320neo	allows analysis by model and variant
Airline / operator	Lufthansa	assigns the aircraft to a fleet, important for wet lease
Place	Munich Airport	shows where you saw the aircraft
Date and time	Oct. 15, 2026, 14:20	dates the sighting and helps with duplicates
Source	read / photo	documents how certain the entry is
Serial number (optional)	MSN	connects the sighting to the airframe, even after re-registration

The serial number (Manufacturer Serial Number, MSN) is the field that many beginners leave out and later regret. What MSN, c/n and line number are about is explained in the article MSN, c/n and line number. A more detailed blueprint for the complete logbook is in the guide Documenting sightings.

Where the target list comes from

Without a target list, a collection is just a long list. Only the comparison with the complete fleet shows you how far along you are. Three kinds of sources play a role.

Online fleet databases. Platforms such as Planespotters.net keep fleet lists by airline and by type, often supplemented with serial number, delivery and previous registrations. How to use such databases for your collection is shown in Using Planespotters.net as a fleet database and the overview Fleet databases compared. For military aircraft there are dedicated sources, such as Scramble.

Official registers. Some aviation authorities put their register online publicly. The British CAA offers G-INFO, a freely searchable database of all G registrations, and the US aviation authority FAA an online lookup by N-number, name or serial number. In Germany it is different: the aircraft register (Luftfahrzeugrolle) of the Federal Aviation Office (Luftfahrt-Bundesamt) is not a freely searchable database. Private applicants receive data from it only in narrowly limited cases, for example if they credibly show that they need it for legal claims in connection with air traffic – so it is hardly suitable as a reference for the hobby. How exactly this works is in the piece Querying the aircraft register.

Community and magazines. Spotter clubs, forums and magazines often publish new arrivals, departures and re-registrations faster than databases catch up. An overview of German-language contact points is under German-language aviation forums.

Logging a fleet completely: step by step

The first hits come almost by themselves when collecting fleets. At a big hub such as Frankfurt Airport or Munich Airport, after a few visits you have a decent part of the aircraft based there in your logbook. After that it gets tough. This is how you proceed systematically:

You will find detailed strategies specifically for ticking off large fleet lists in the piece Logging fleets completely.

Why the last aircraft are so hard

Stubborn gaps almost always have an understandable reason:

• Maintenance: Major checks take weeks. An aircraft that sits in the hangar during that time cannot be seen at the fence.
• Another base: Many airlines distribute their aircraft across several locations. With large low-cost fleets like that of Ryanair, it can take a while until a particular aircraft shows up at your home airport.
• Leasing and wet lease: Some aircraft temporarily fly for other airlines, partly in a different livery or under a foreign flight schedule.
• Storage and retirement: If an aircraft is parked permanently, it is still in the fleet but practically unreachable for you.
• Outlying routes: Individual sub-fleets fly almost only certain destinations. If you know which routes a type serves, you can increase the hit probability considerably.

How to find out where a particular aircraft currently is is explained in the guide Finding and tracking an aircraft by registration.

At the spot: how to log quickly and reliably

In logging, reading correctly is what counts. One swapped letter turns a new sighting into a phantom entry. A few habits help:

• Read the registration completely. Especially in long series of an airline, aircraft often differ only in the last letter. Binoculars or a quick proof photo are worthwhile.
• Know where the registration is. On the rear fuselage, sometimes under the wings, occasionally at the nose gear bay. Where it is prescribed is explained in Where the registration must be on an aircraft.
• Note immediately, sort later. At the fence an abbreviation is enough; you add the details in the evening. Tips for this are under Logging sightings quickly at the spot.
• Don’t guess the unreadable. If the registration was only half visible, mark the entry as uncertain and check it later. How to do that is shown in Identifying an unreadable registration.

Good logging spots are places where aircraft pass slowly and close: taxiways, observation decks, parking areas. At the Munich Airport visitors’ hill or the Zeppelinheim viewing platform you get to see many movements per hour – ideal for filling a fleet quickly.

Which type of collector are you?

Not every project suits everyone. The choice depends on how often you are at the airport and how far you want to travel.

Analyzing: what your logbook tells you

A cleanly kept logbook is more than a tally sheet. After a few months you can read off which types dominate at your airport, which airlines only rarely come and how traffic changes over the year. With the serial numbers you can even see how old the aircraft you log are – how that works is described in How old is this aircraft?. Ideas for analyses are provided by the piece Analyzing your own spotting statistics, and how rare a sighting really is is covered in How rare is my sighting?.

Common mistakes when collecting registrations

If you stand at the fence logging, you should also know the rules: what is allowed around airports is summarized in the article Is plane spotting allowed?. And before you add military airfields to your logbook while traveling, take a look at the Kalamata case of 2001, in which spotters stood trial after an open day at a Greek air force base.

Conclusion

Collecting registrations is plane spotting with a system. Instead of random sightings, you have a collection that you can match against fleet lists, analyze and complete deliberately. The basics are quickly laid: a fixed collecting rule, a logbook with clear fields, the serial number as an anchor against re-registrations and a current target list. The rest is patience, a bit of detective work and the joy when, after months, the last missing registration finally rolls over the threshold.