I don't understand the difference between the C501/551 and the C500/550/560.
Why two different ratings? Isn't it the same a/c?

Correct. The 501 is the same aircraft as the 500 and the 551 is the same aircraft as the 550. Unfortunately EASA has categorised them into two different categories and license endorsements. This results in two different type ratings.

Operation and training of the C500/550 series aircraft poses some special challenges within EASA rules, because the aircraft are categorised both as Single Pilot Complex High Performance Aeroplanes (SPCHPA) and as Multi Pilot Aeroplanes (MPA) imposing different training and experience requirements on two aircraft that are technically almost 100% alike. The types and variants are:

1) Depending on s/n, most typical MTOM shown

The list of actual differences between the single- and multipilot aircraft is very short:

a) The C550 multi pilot aircraft is technically exactly equal to the C551 single pilot type. The only differences between the two are:

• the slightly higher MTOM of the C550: 13.300 lbs for the C550 and 12.500 lbs for the C551;

• a mandatory yoke mount transponder ident-button on the C551 that is not required on the C550.

b) The C500 multi pilot aircraft is technically exactly equal to the C501 single pilot type. Between these two types there is not even a difference in MTOM, only the yoke mount transponder ident-button.

Single- and multi-pilot types generally have different MEL-requirements, which is managed by the operators approved MEL.

Note: Cessna offers a conversion from 551 to 550 and vice versa by simple Service Bulletin SB550-11-3. These conversions are rare though, because in the main market, the USA, a C550 can be flown single pilot by means of a single pilot licensing exemption for the pilot.

Why? What about the MTOMs?

The reason for this odd situation is routed in the certification history of the aircraft. The initial Citation 500, 50 years ago known ans "Fanjet 500", was a multipilot aeroplane. The concept that a jet can be operated single pilot simply wasn't proven yet. The slow speeds ("Slowtation") and the benign handling characteristics made the C500 an ideal candidate for the first single pilot business jet and a few years after the introduction of the C500 Cessna offered a single pilot variant, called the C501.

The larger and heavier C550, appeared a few year later. The 550 is a much more capable airplane, but it posed a different challenge to the marketing and certification staff at Cessna. While equally practical as a single pilot jet, it weighs more than 5,7 tonnes (12.500 lbs). Back then in the 1970s, any aircraft with an MTOM above 12.500 lbs had to be multi pilot.

So in order to offer a single pilot variant for the larger model as well, Cessna capped the C551 at 12.500 lbs MTOM. This results in a still capable airplane but with a much reduced useful load (-800 lbs), as both the C550 and the C551 are technically identical and field the same empty weights.

Today, single pilot business jets above 12.500 lbs such as the CJ4 and the Phenom 300 are not unusual, but back in the 1970s this was not an option Cessna pursued.

In the US all this is not a problem, as the entire family C500,501,550,551 and 560 is one type rating with single pilot exemptions available for all variants therein. EASA has not followed this example and has blessed us with two different type ratings in two very different licensing categories – for the same aircraft.


Differences between C500 and 550 series

The differences between the C500 and C550 series (and C501 and C551 respectively) are mainly performance and mass and balance due to the more powerful engine variants and higher fuel capacity utilised in the C550 and C551. The handling characteristics and systems are mostly identical.

Differences training is required between the C500 and 550 and the C501 and 551.