Okay, a big plane with a hump. You've spotted a 747.

Is that it? What kind of 747? When was it built and for whom? Knowing how to identify which 747 series a plane is from can give partial answers to some of these questions.

If you are a true plane spotter, none of this matters. You want to identify the plane model accurately because different models exist. The following notes should help.

The 747 has been in production for over twenty-five years, and while general features like body shape and engine placement have remained constant, many different models have been built.

Boeing Numbering and Naming History

Since the late 1950's, when it brought out the 707, Boeing has adhered to a simple system for identifying its commercial jet aircraft. The initial versions of any particular model (707, 727, 737, 747) start their design life as ``100'' series aircraft (viz., 707 ``100'' series or 707-100, etc.).

Within a series, Boeing further distinguishes among planes sold to different customers, with the customer sub-identifier. Pan American was the first 707 customer, which it ordered in 1955 (three years before the first delivery). It received the designation ``21,'' so Pan American's 707-100's were known as 707-121's. Before any additional orders were received, Boeing randomly assigned sub-identifiers to most of the world's major airlines. United was assigned 22, American 23, Continental 24, etc. The numbers were apparently assigned in approximately decreasing order of liklihood of placing an order.

Of course, not all airlines ordered the 707. For example, Eastern, which had the assigned number of 25, never ordered the 707, so one will never read of a ``707-125.'' Once assigned a sub-series number, an airline effectively ``keeps it'' for its existence. If an airline goes bankrupt or ceases to exist as a separate entity, its sub-series designator dies with it.

The series follow each other in order (747-100 series is followed by 747-200 series, etc.). Usually, only one series is in production at any given time. However, there have often been periods of a year or more when two successive models have been in production. Not every series number makes it into use as a production model. The series numbering serves Boeing internally to keep track of designs and redesigns, and designs are adjusted in consultation with important customers (mainly the major commercial airlines). In the case of the 757, 767, and 777, the first planes delivered were already in the 200 series.

In addition to the successive series, there are also specialized models designated by letter codes (F, C, SP for the 747) which may occur in more than one series. These models are also referred to as constituting ``series,'' although they overlap the -100, -200, etc. series designations.

Some other relatively minor model differences are sometimes also indicated, as in the distinction between 747-200 and 747-200B, both vanilla passenger models.

The 747 in General

The 747 was launched with an order from Pan American in 1965. Its mission: to be the ``queen'' of the world's airline high capacity long haul fleet. The first prototype was rolled out in September 1968. Production models began to roll out in the summer of 1969.

Distinctive Features:

The Hump
The distinctive ``hump'' on the front third or so of the fuselage was designed to house the cockpit and a First Class lounge. The upper deck of the initial -100 series has three widely spaced windows on each side. On the port side there is a small emergency door, located just aft of the cockpit window.

Landing gear
Eighteen (18) wheels: two for the nose wheel, and four ``bogies'' of four; two under the fuselage, and one located on each wing.

Variations on the theme

Over the years, external changes that can be easily identified (by spotters) fall into three main categories: the fuselage shape (the length of the upper deck), the engine types (distinguished by differences in engine and pylon designs) and wings (wingspan, flap housings, and ``winglets'').

The -100 series

The 747-100 began commercial service in January 1970, with launch customer Pan American, followed shortly thereafter by TWA (February), American (March), BOAC (April), Lufthansa (May), Air France (June), United (July), and Japan Airlines (July).

General statistics (all -100 series):

Maximum takeoff weight:
Passenger models: 500,000 to 600,000 lb.
F-model: 710,000 lb. (320 metric tons)

225 ft. (69 m)

196 ft. (59.7 m)

Cabin Width:
20 ft. (6 m)

63 ft. (19 m) at the tail.

Seating Capacity:
360-490 (except SR model, 550)

4000-6500 nautical mi. (4600-7475 mi., 7400-12000 km)

Depends on load, cruising speed, etc.

Pratt & Whitney; four JT9D by-pass engines with 43,500 pounds of thrust apiece.

External Appearance Changes

The 747-100's delivered during late '69 and through mid-1970 were all very similar in external appearance, if not identical. Cabin arrangements, of course, varied widely, but all initial configurations (even for domestic carriers like United) included lavish First Class lounges on the upper deck, all connected to the main deck by a somewhat compact but nevertheless elegant spiral staircase. In those days, there was no ``business class,'' so all had coach and first class seating arrangments. Eighteen in first and 360 in coach was a common configuration.

The -200 Series

In late 1970, Boeing offered an improved ``higher performance'' version of the 747, the 747-200 series. Most changes were with thrust ratings of newer Pratt & Whitney engines, greater fuel capacity (and thus range), higher gross takeoff weight, and many other more minor changes. Among the first airlines that took delivery of this version were Northwest and Air India. Externally, there is very little to distinguish initial 200 series from 100 series...

Except for one thing: the upper deck windows. Plane spotters at the time thought that they could easily distinguish between the two types because in late 1971, 747's started to appear with ten (not three) windows on each side, effectively ``filling in'' the widely spaced three windows of the 100 series. Most, but not all 200 series aircraft have this feature. Boeing decided to offer the ``ten-window look'' as an option in 1970 to all 747 customers, including those still taking delivery of 100 series aircraft, and eventually made it a standard feature of the -100. Therefore, some 747-100 aircraft (for example, several received by Japan Airlines and All Nippon Airways) were delivered with the ``ten-window look'' on the upper deck.

[Click here for a 747-200B originally purchased by KLM, now maintained by KLM for Garuda Indonesia.]

To confuse things further, the very first -200 series aircraft only had three windows on top, making them appear to be -100 series aircraft. (Northwest and Air India received -200's with both three and ten windows). Additionally compounding things was United, whose management at the time felt it needed to get the ``200 look'' look on its original batch of -100's, and sent several back to Boeing in 1972 for more upper-deck windows, so that all of its newer -100's (all by then being delivered with ten windows standard) would appear the same.

One final note on upper deck windows. Customers had the option to ``blank out'' windows at the factory or later after the aircraft were in service. One may see a ``ten window'' pattern with only seven or eight windows, because the windows on either end are plugged or blanked out. (A faint outline of the window opening is generally visible.) Even on the original three-window configuration, some customers opted to blank out one of the three to accommodate new galley configurations (as Pan Am did with many of its -121's during the 1980's, on the left side only).

The moral of the story: don't jump to conclusions based solely on the number of windows. A truly dedicated plane spotter will search out an aircraft's registration number first (and, assuming they interpret it correctly), which will always reveal its true lineage.

During the remainder of the 1970's, the only other significant changes to the 747's appearance (for -100 and -200 models) revolved around engine types. Both GE (General Electric) and Rolls Royce (RR) introduced their own ``high bypass'' engines to compete with Pratt and Whitney. GE engines could be easily spotted by their relatively large cowling area (the cowling is the covering that surrounds the engine), whereas RR engines had relatively stubby-appearing exhaust cones behind the cowling area. British Airway received most of its -200 models with RR engines (only after taking delivery of a dozen or so Pratt-powered -100 models) and GE engines eventually wound up powering the All Nippon Airways -200.

Introduction of the -200 did not end production of the -100. The -100 series continued to be offered for many years because the target market for the -100 was somewhat different than for the -200. The -100 was targeted at shorter-range high-capacity routes. United, for example, continued to receive new -100's until 1973.

``SR''(Short Range)

Another reason for the continued production of the -100's was the ``SR'' (for Short Range) configuration. All Nippon Airways (ANA) as well as JAL took delivery of quite a few -100 SR's which did not possess the more powerful engines, fuel capacity and other upgrades of the -200. These aircraft were (and still are) used almost exclusively for internal Japanese routes, where high capacity is needed (in all-coach configurations they seat up to 550!) but long-range capability is not (typical flight sectors are under 1 hour). While ANA and JAL continued to acquire -100's for domestic routes, they also continued to receive -200's for international routes. Don't get the wrong impression about the -100's: the SR's operated by ANA and JAL on such short routes are the exception, not the rule. Most -100's operate on what are still relatively long haul sectors, generally 3,000-5,000 miles.

The ``F'' (for Freight) Series

The 747 actually began its design life as a cargo aircraft proposal for the US military. The contract went to Lockheed, which produced the C-5A. Most of the new technology (in particular the new higher-thrust by-pass engines) was developed to meet military requirements rather than those of the commerical market. The 747 wound up with its distinctive hump as a result of earlier military design proposals in which its nose swung up to permit loading of outside cargo on the lower deck. The cockpit and support crew would be housed ``out of the way'' in the upper deck ``hump.''

Therefore, designing the cargo version of the commerical 747 was a relatively easy exercise, based on the military design experience. For plane spotters, the first thing one notices is the near-total absence of windows, save one or two in each side of the upper deck, and several (associated with passenger doors) on the lower deck. The outline of the swing nose (which pivots up toward the cockpit) and a large cargo door (on the port side aft of the wing) also are readily apparent.

The major performance statistic for the cargo version is that its takeoff weight (depending on engines selected) is much greater than that of the passenger models.

The 747F was launched by Lufthansa in March 1972, followed shortly by Northwest.

Since the ``F'' model is more of a functional option rather than one associated with a particular series (i.e., -100, -200, etc.) it tends to take on whatever characteristics that these series may have. In the case of the -100 and -200 models, there are no external distinguishing characteristics other than those described above. However, although the first F model introduced by Lufthansa was in the 100 series, it incorporated many of the -200's upgrades and improvements (including higher rated thrust engines). Shortly afterwards, the F model was only offered as a -200. It is now only offered as a -400 model, although it retains the 100/200-sized hump. For plane spotters, however, things can get confusing since many passenger model -100's have been converted into freighters, especially during the last five years or so. Many -100 passenger models built 25 years ago are being retired: some wind up as scrap metal, other languish in the desert, while some are converted to freighters.

The ``C'' (for Combination) Series

From the start, Boeing had intended to have a combination or ``combi'' version for its 747 model line, as it had on the 707 and 727 models. The ``C'' version was an option which permitted carriers to operate the 747 with a combination of freight and passengers, or all freight, or all passenger, depending on the market need.

Unlike the ``F'' model, it retains all of the passenger windows of ``pure'' passenger models. It may or may not have an F-style ``swing nose'' door in front, but all retain the side cargo door on the aft starboard of the fuselage, just behind the wing. Interior flooring is strengthened as in the ``F.'' A typical mixed cargo/passenger configuration uses a ``condensed'' seating arrangement extending from the nose to just aft of the wing, at which point a wall separates the cabin from the remaining rearmost portion, in which cargo can be loaded. The first operator of the ``C'' model was World Airways, which took delivery in 1972.

The SP Series

In 1973 Pan American expressed interest in acquiring an aircraft capable of flying extreme long range routes that did not produce passenger loads sufficient to justify use of a 747. Routes they had in mind were JFK-Tokyo non-stop, JFK-Riyiad, etc. In August 1973, Boeing announced the ``Special Performance'' or SP version of the 747, capable of flying 7000 miles with a (smaller) full load.

Pan American immediately ordered 10 for delivery in 1976.

External Characteristics: short and plump!

Of all the 747 derivatives produced to date, the SP series remains the most distinctive and easy to recognize. What strikes one immediately is the much shorter and ``stubbier''-looking fuselage. In order to reduce weight (and hence increase range with wings that remained the same size), frames were removed ahead of and behind the wing, resulting in a reduction of 48ft in length from the standard 225 feet. Although the upper deck ``hump'' remained the same size, its starting point proximity on top of the fuselage moved to mid-point. Seating capacity was naturally reduced, ranging from 240-320 in a mixed-class configuration.

Another difference which is readily apparent is in the tail, which Boeing made taller by nearly 10 ft (in order to compensate for directional stability). From a distance, it appears much more ``pointy'' than the standard 747 tail, and it is shared by no other series 747. Other unique attributes include elimination of the rather large underwing ``flap track housings'' which guide the flaps smoothly up and down (the flaps were also modified to be a simpler design).

All SP's were manufactured with the ``10 window look'' on the upper deck, as were all 747 -100/200 models from the mid-1970's onward. Although SP's were available with either Pratt & Whitney or Rolls Royce engines, most were ordered with Pratts.

Production History

Launch customer Pan American introduced SP service in April 1976 between LAX and Tokyo and JFK and Tokyo. Other early customers included Iran Air (which still operates its original fleet of four as of October 1995), South African Airways, Saudia, and CAAC (the Chinese state-run carrier). [ftnt. 1] The total production of the SP series was a meager 45, the majority of which were built between 1975 and 1980.

The -400 series, when it came out, it had nearly the same range as the SP, but could carry a full load of passengers. In 1989, the year that the -400 began production, SP production was dropped. However, it was not simply the -400's introduction that killed off the SP; Boeing received most of its SP orders in the period 1974-80. There was almost no production of the SP between 1981 and 1989.

The -300 Series

The first major external change in the appearance of standard-model 747's came with the introduction of the -300 series in 1983. An extension of the upper deck ``hump'' by a number of feet, resulting in the hump appearing to begin about the midpoint in the fuselage rather than the front third. Additional windows were added, usually an additional 10 or so (this varies by customer). Actually, two sets of windows are separated midway by a new style (and size) of emergency door, located on both sides of the upper deck fuselage area.

Additional passenger capacity resulting in ``extended upper deck'' varied depending on whether they were configured for first, business or coach seating, but ranged from 16 to 80. A new galley area was also included, generally located at the rearmost portion.

Aside from the upper-deck extension, there are virtually no external changes to disguish it from the -100 and -200 series.

Swissair introduced the -300 model in 1983, followed shortly by Japan Airlines.

At the request of the Dutch carrier KLM, Boeing agreed to set up a special assembly area to permit ``-300 retrofits'' of its -200 series aircraft. KLM elected to have several of its -200's sent to Boeing for the modifications, which involved removing the existing 100/200-style hump and replacing it with the extended upper deck of the -300. No other carriers took advantage of this. KLM also took delivery of new -300's, so unless one notes the tail number, it is nearly impossible to identify which KLM -300's were delivered new and which ones started out life as -200's.

The -400 Series

The -400 series represented Boeing's attempt to truly update all major systems in its aircraft to state of the art technology (mid- to late 1980's technology). Although the configuration of the -400, from a passenger-seating perspective, is nearly identical to that of the -300 (with the same upper- deck extension), the -400 series received all-new avionics, wiring, air conditioning, control systems, etc. It was designed with a glass cockpit (flat panel displays) with sophisticated software-driven monitoring systems.

Externally, the most distinctive feature are the ``winglets'' which rise six feet (two meters) vertically from the wing tips. The wings were also completely redesigned and feature a wider span (by 17 feet) than those of earlier models and a smoothed-out faring area (where the wing is attached to the fuselage). Otherwise, the external profile of the -400 is identical to that of the -300 series.

Engine pylons and cowling/exhaust pipe designs were also new, with each of the three major engine suppliers coming up with slightly different designs. Pratt & Whitney introduced the first in a series of more powerful engines, a derivative of which has been used to power the new 777 (between 74 and 90 thousand pounds thrust). The maximum gross takeoff weight of the 747-400 ``F'' is nearly 1 million pounds.

With all the engineering changes, the 747's range increased to 7800 miles, as did its maximum takeoff weight and fuel capacity.

Northwest introduced the -400 in 1989, followed shortly by United, British Airways, Singapore Airlines, and Lufthansa in 1990.