The British Aerospace 146 is a four engined medium size jet airliner, that started its development as Hawker-Siddeley HS146. The lack of a suitable engine was the reason that the company chose to make a design with four engines. As the development was halted for several years by the time the work was started again Hawker-Siddeley had gone up into British Aerospace and the aircraft became known as British Aerospace 146, in short BAe146. The second generation of the family was marketed as the Avro RJ, while the third generation was to become the Avro RJX.

Unlike many other regional jets of this size the BAe146 features high mounted swept wings, with four engines in pods under the wings. It also has a T-tail and a tail cone that can be opened as a speed brake. The two wheel main gear retracts in the fuselage, there is hardly a streamline body to hold the gear. All in all the aircraft is not so difficult to recognise, given its size and basic appearance.

The different versions of the BAe146 / Avro RJ(X) family can be distinguished by looking at

• the length of the fuselage
• the shape of the engine nacelles
• the presence of a large cargo door in the left rear fuselage
• the presence of cabin windows
• the presence of a refueling boom above the cockpit
• the presence of anti-missile equipment

These are the first and second generation of the shortest version. Obviously it has fewest number of cabin windows, but still a lot to count. The best way to distinguish the version is to look for the relative length of the fuselage.  

The Avro RJ70 has different engines and improved avionics and interior, but is externally the same as the 146-100.

The Royal Air Force operated a VIP version of the Series 100. It was designated BAe146 CC2. Externally it is nearly the same as the standard passenger version. However, it has pods at the side of the rear fuselage to counter missile attacks.

British Aerospace foresaw a market for a military version based on the BAe146-200QC/QT. It had the marketing name BAe146STA, for Side-loading Tactical Airlifter. Only a Series 100 was fitted with a dummy refueling probe above the cockpit for demonstration purposes. No actual BAe146STA was built.

The second version is the Series 200. It is nearly 2.5 metres longer than Series 100. Again, it is best to compare the relative dimensions, as alternative for counting cabin windows. 

As with the RJ70 the Avro RJ85 is the updated version, without external changes compared to the BAe146-200.

The Quick Change (QC) variant has a large cargo door in the left rear fuselage, but retains the cabin windows. This differentiates it from the Series 200QT. The aircraft can be quickly converted from passenger to cargo aircraft and vice versa.

Two Series 200QC were later acquired by the Royal Air Force and given designation BAe146 C3. They differ from the original version by the anti-missile pods attached to the rear fuselage.

Especially for the parcel market British Aerospace developed a dedicated cargo version, called Quiet Trader (QT). The Series 200QT is based on the Series frame. Compared to the Quick Change version it has metal plugs in place of the cabin windows.

The longest version is the Series 300, which is a further 2.3 metre stretch of the Series 200. It has no additional emergency exits, so you have to compare the lengths again, or the relative dimensions.

The Avro RJ100 is the upgraded version, with no external differences compared to the BAe146-300.

The BAe146-300 also got a full freighter variant, the Series 300QT. Compared to the standard version the BAe146-300QT has no cabin windows.

The third generation of the British Aerospace 146 series was no success. Only two aircraft were built, of which one RJX85. This has the dimensions of the RJ85, but different engines in longer nacelles with a single exhaust.

Of the Avro RJX100 one aircraft was built as well. This has the dimensions of the RJ100, so it is longer than the RJX85. It has the same engines in longer nacelles with a single exhaust though.