Landing gear as an identification feature: recognizing aircraft types by wheels and axles

The jet comes in backlit, the engines are just dark blobs, the cockpit windows cannot be made out at all. What you do see: two landing gear legs, and on each hang three pairs of tires one behind the other. That almost settles it. The landing gear is one of the most reliable features for identifying an aircraft type, especially on approach and at a distance. This guide shows you which configurations exist, how to count wheels and axles quickly and which types you can narrow down reliably from that alone.

Reading landing gear: the short answer

You read a landing gear in two steps: first you count the wheels on one main gear leg, then the number of main gear legs. The nose gear plays almost no role here, because on nearly all airliners it carries two wheels. These two numbers yield a small number of patterns, and each pattern fits only a few types.

Physics is behind the logic: an aircraft must not load the runway more than it can bear. The heavier the aircraft, the more tires it needs to spread the weight. That is why landing gear grows with takeoff weight – from the two-wheel leg of the short-haul aircraft through the four-wheel bogie of the classic widebody jets to the six-wheel bogies of the heaviest twinjets.

The basic terms

A few terms make the following sections easier:

• Nose gear: the leg under the nose. It steers the aircraft on the ground and on airliners usually carries two wheels side by side.
• Main gear: the legs that take most of the weight on touchdown. They sit under the wing, on the fuselage or both.
• Dual wheel: two wheels side by side on one axle – the standard solution on narrowbody jets and turboprops.
• Bogie: a frame at the end of the gear leg that carries several axles one behind the other. Two axles make a four-wheel bogie, three axles a six-wheel bogie.
• Center gear: an additional main gear leg in the middle under the fuselage, between the two outer legs.

When you look at a bogie on approach, the easiest way is to count the axles from front to back. Two pairs of tires one behind the other mean four wheels per leg, three pairs six.

Two wheels per leg: narrowbody and regional

Most aircraft you see at a German airport stand on two main gear legs with two wheels each plus a two-wheel nose gear – six wheels in total. That includes the entire A320 family up to the A321neo, all generations of the Boeing 737, the Embraer E-Jets, the A220 and the CRJ family.

Within this large group, the wheel count therefore does not help. But there are details on the landing gear that still separate them:

• Boeing 737: The main gear swings inward into the fuselage without being covered by outer doors. In a flyover you therefore see the wheel hubs as dark circles on the belly of the fuselage. On the Boeing 737-800, that is one of the quickest features against the A320. How to tell the 737 generations apart is covered in the guide Telling the Boeing 737 Original, Classic, NG and MAX apart.
• A320 family: Here, doors close the wheel wells after retraction. From below you see a smooth underside of the fuselage.
• Ground clearance: The 737 stands noticeably lower than the A320. The short landing gear stems from its original design and explains the flattened-at-the-bottom engine inlets of the later generations.

The exception: four wheels on a narrow fuselage

A narrowbody with four-wheel bogies stands out immediately because it is rare. The most important example is the Boeing 757-200. It also stands conspicuously high on its legs. If you see a long, slender fuselage, tall legs and two pairs of tires one behind the other, you are almost at the answer with the 757. Against the A321, the landing gear is even the surest feature: the A321 has only two wheels per leg. The distinction from its sister, the 767, is explained in the article Telling the Boeing 757 and 767 apart.

Four wheels per leg: the classic widebody jets

Two main gear legs with one four-wheel bogie each are the standard picture of widebody jets. In total that is ten wheels. This group includes:

• Airbus A300 and A310
• Airbus A330 in all versions, including the A330neo
• Airbus A350-900
• Boeing 767 in all versions
• Boeing 787-8, -9 and -10
• Lockheed L-1011 TriStar (historic)

For the question “which widebody jet exactly”, the landing gear therefore helps only indirectly here. But it already rules out a lot: if you see four wheels per leg, it is not a 777, not an A350-1000 and not an A340. For the fine work you then need the nose, cockpit windows and wingtips – the guides A350 or Boeing 787? and Identifying aircraft types by nose and cockpit windows help with that.

One detail is worth noting on freighters: the A330-200F has a distinct bump under the nose. It houses a lower-mounted nose gear so that the cargo deck sits level on the ground. More in the guide Identifying cargo aircraft.

Six wheels per leg: 777 and A350-1000

Three pairs of tires one behind the other on each main gear leg, 14 wheels in total with the nose wheel: that is the signature of the heaviest twinjets. Among current passenger jets, there are only two families of them.

• Boeing 777: All versions stand on six-wheel bogies, from the 777-200 through the 777-300ER to the 777-9. The landing gear is the strongest single feature here and is visible already far out on final approach.
• Airbus A350-1000: The stretched A350 also has six wheels per leg, while the A350-900 gets by with four. For telling apart within the A350 family, the landing gear is therefore worth its weight in gold.

Between the 777 and the A350-1000, other features decide: the A350 has a dark mask around the cockpit windows and upward-curved wingtips, the 777 raked wingtips on the -300ER or folding tips on the 777X. How to tell the 777 and 787 apart is described in the article Telling the Boeing 777 and 787 apart.

The third leg: center gear

A landing gear leg in the middle under the fuselage is a rare feature on airliners – and therefore a very telling one.

• Airbus A340-200 and -300: two four-wheel legs plus a two-wheel center gear, twelve wheels in total.
• Airbus A340-500 and -600: The center gear has grown into a four-wheel bogie because the aircraft are much heavier. In total there are 14 wheels.
• McDonnell Douglas DC-10-30/-40 and MD-11: two four-wheel legs plus a two-wheel center leg. The short DC-10-10 did not have this leg.

With the A330 and A340 in particular, the center gear often saves the identification when the engines are barely countable in backlight. In side-on pictures it is only a dark spot between the main gear legs; from the front you see it as a third group of wheels. The A340-600 with its four-wheel center leg and very long fuselage is then hard to mix up. Everything else is in the guide A330 or A340?.

With the historic three-engine jets, the center gear helps as well: the Lockheed L-1011 TriStar had none, while the DC-10-30 and the MD-11 did.

Four main gear legs: 747 and A380

The two big four-engine jets with an upper deck spread their weight over four main gear legs – two under the wings, two under the fuselage.

• Boeing 747: four identical-looking legs with four wheels each, plus the two-wheel nose gear – 18 wheels. That applies to all versions up to the 747-8.
• Airbus A380: two wing gear legs with four wheels each and two body gear legs with six wheels each – 22 wheels in total. The six-wheel bogies under the fuselage look like two wide blocks of wheels on approach.

The differences between the two giants go far beyond the landing gear – upper deck, nose, wings. You will find the comparison in the article A380 or Boeing 747?; the type page on the A380-800 provides the key figures.

Overview: landing gear configurations by type

Type / family	Main gear legs	Wheels per leg	Center gear	Wheels in total
A320 family, 737, E-Jets, A220, CRJ	2	2	no	6
Boeing 757	2	4	no	10
A300, A310, A330, A350-900, 767, 787	2	4	no	10
Boeing 777, A350-1000	2	6	no	14
A340-200/-300	3	4 / 4 / 2	yes, 2 wheels	12
A340-500/-600	3	4 / 4 / 4	yes, 4 wheels	14
DC-10-30/-40, MD-11	3	4 / 4 / 2	yes, 2 wheels	12
Boeing 747	4	4	–	18
Airbus A380	4	4 (wing), 6 (fuselage)	–	22
Antonov An-124	Dual-wheel rows on the fuselage	–	–	24
Antonov An-225	Dual-wheel rows on the fuselage	–	–	32

The totals include the nose gear in each case. The table is meant as an identification aid: it narrows down families, and you then settle the exact variant through length, engines or registration.

Heavy lift and military: wheels in long rows

Counting works differently on the big freighters of the Antonov family. Instead of a few legs with bogies, they carry many dual wheels one behind the other in long fairings on the sides of the fuselage.

• The Antonov An-124 stands on 24 wheels, four of them on the dual nose gear. The nose gear can be lowered so that the aircraft tilts forward over the raised nose for loading.
• The now destroyed Antonov An-225 had 32 wheels: seven dual wheels on each side of the main gear and four wheels at the front. It is historic, but its landing gear remains a classic among spotters.

Many military transports with a high-mounted wing also use this principle: because there is no room under the wing for long legs, the main gear sits in pods on the fuselage, with several wheels one behind the other. The Lockheed C-130 Hercules and the Airbus A400M are good examples. How to tell the transports apart is covered in the guide Identifying military transports.

Turboprops: where the landing gear disappears to

On propeller aircraft, the main gear legs usually carry two wheels. More interesting is where they retract to – on the two most common regional turboprops, that is the distinguishing feature par excellence.

• ATR 72: The main gear folds into fairings low on the side of the fuselage. The legs therefore stand close to the fuselage, and under the high-mounted wing the nacelle is free of landing gear. Example: the ATR 72-600.
• Dash 8: The main gear retracts into the engine nacelles. The long legs therefore hang directly under the propellers, which makes the Dash 8-400 easy to recognize on approach too.

Further features such as tail, fuselage length and propeller blades are described in the article Telling the ATR 42/72 and Dash 8 apart.

When and where you see the landing gear best

The landing gear is a feature for particular situations. If you know when it is visible, you can use it deliberately.

On departing aircraft, by contrast, the gear is often already retracted a few seconds after liftoff. If you want to read landing gear deliberately, stand on the landing side. The pros and cons of both situations are explained in the post Landings or takeoffs?. Good views of landings are offered, for example, by the Munich visitors’ hill and the Zeppelinheim viewing platform in Frankfurt. For heavy freighters, the Leipzig/Halle observation deck is worthwhile.

Typical mistakes when counting landing gear

• Saw only one leg: In side views, the near leg often hides the far one. A center gear also lies in the shadow of the fuselage and is easily lost.
• Bogie tilted: Before touchdown, many bogies hang tilted. Then two axles look like one if you look exactly from the front. A look from the side at an angle settles that.
• Four wheels does not mean 787: Many widebody jets have four wheels per leg. Here the landing gear only rules things out; it does not identify.
• Variants by landing gear: Within a family, the landing gear usually stays the same. Exceptions such as the A350-900/-1000 or A340-300/-600 are precisely why they are so valuable.

The landing gear is one building block among several. Combined with engines and the basic rules from Airbus or Boeing?, you almost always arrive at the right type. If you are just starting out, the introduction Identifying aircraft types for beginners helps you.

Who builds the landing gear?

Landing gear often does not come from the aircraft manufacturer itself but from specialized suppliers. One of the big names is the landing gear division of Safran, which supplies landing gear for numerous Airbus and Boeing programs. For identification at the fence that does not matter, but for understanding it does: landing gear is one of the most heavily stressed components of an aircraft and is designed precisely for the maximum weight of each program. That is exactly why the wheel count and axles grow with size – and exactly why you can infer the size class from the landing gear so reliably. The manufacturer profiles on Airbus and Boeing show you which programs are behind them.

Conclusion

Landing gear follows clear logic: more weight needs more wheels. That yields a few patterns you can memorize quickly – two wheels per leg for narrowbody and regional, four for the classic widebody jets and the 757, six for the 777 and A350-1000, a third leg for the A340 and MD-11, four legs for the 747 and A380. With that you often narrow down a type before you can even properly see the engines or cockpit windows.