Cessna C525 Citation Jet

Engines and engine control

The FJ44-1A engine is a twin spool co-rotating, axial flow turbofan engine with medium bypass ratio (3,3 : 1), mixed exhaust and high cycle bypass ratio.

The Cessna C525 Citation mounted engines produce approx. 1900 pounds of thrust at sea level iaw ISA. Thrust control is managed by throttle lever input to a hydro-mechanical fuel control unit mounted on the fuel pump and driven by the accessory gear box. Thrust attenuators, consisting of panels extending into the exhaust steam are controlled by an AUTO/STOW/TEST switch and the thrust lever quadrant.

Cessna C525 Citation engine systems include oil system, fuel system and ignition system. Newer versions of the Cessna C525 Citation family (branded with "+") (CJ1+, CJ2+, CJ3, CJ3+, CJ4 and M2) feature FADEC, the engines of the Citation Jet do not have this feature and need to be manually controlled during the engine operation.

All of the performance parameters needs to be manually calculated based on the performance charts in the AFM.  As it can easily happen to operate the engines out of limits, it is of utmost importance to observe and respect the engine parameters when setting thrust in any phase of the flight. Engines of the Cessna Citation Jet - CJ are not protected by computerized systems against over stress.

Thrust attenuators

Other feature that differs the Cessna Citation Jet (CJ) from the other variants are thrust attenuatorsThrust attenuators consist of vertical “paddles” which, when deployed, insert themselves aft of the engines into the exhaust gas stream, providing a reduction of the forward thrust of the engines. This feature is the simplified "reverse thrust" feature well-known from the other jet types. However none of the Cessna C525 Citation family variants is equipped with thrust reversers.

When stowed, the thrust attenuators streamline themselves along the engine pylon aft of the engine nacelle.

Operation of the trust attenuators is automatic if the AUTO/STOW/TEST switch is in the AUTO position. When the switch is in the STOW position, the attenuators are locked in place and will not deploy. When holding the switch in the TEST position, the ATTEN UNLOCK LH and/or RH annunciator will illuminate and indicate a functioning unlock warning system.

A hydraulic lock holds the thrust attenuators in the deployed and stowed positions. There is no mechanical lock in the system. The system is fail-safe in that a hydraulic failure in the system could result in a deployment of the thrust attenuators in flight. However, the design of the system is such that in conditions of high speed and/or high thrust the attenuators will be blown back and only a small loss of available thrust will result. When an unlocked thrust attenuator situation occurs, the ATTEN UNLOCK LH and/or RH annunciator on the annunciator panel will illuminate.

Avionics

The Bendix/King CNI 5000 Integrated Avionics System incorporates

  • dual VHF COMM transceivers,
  • dual VHF/VOR navigation receivers with glideslope (the no. 1 Pilot’s receiver having a SBY NAV indicator),
  • a single ADF receiver,
  • a single DME system,
  • dual Mode S transponders and a marker beacon receiver.

The flight guidance system is supplied as standard equipment and is made up of an integrated display which includes an electronic flight instrument system (EFIS) for the RH seat pilot.

Weather radar and dual transponders with altitude reporting and mode S capabilities are also included in the standard package.
Optional Systems are:

  • HF transceiver,
  • ELT,
  • radio altimeter,
  • a second ADF,
  • a second DME,
  • a Flitefone VI satellite telephone system,
  • a cockpit voice recorder
  • a flight data recorder.
  • a GPS receiver
  • other long range navigation equipment 

Detailed operating instructions are provided in the Bendix/King CNI 5000 Integrated Avionics System, Pilot’s Guide.

SPZ 5000 Integrated Flight Control System

The autopilot and flight director system is driven by the IC-500 flight guidance computer. The IC-500 is the heart of the system. The IC-500 accepts input from the VG-14 vertical gyro, copilot’s altitude indicator, C-14 directional gyro, AZ-429 air data sensor, encoding altimeter, AG-222 accelerometer, PC-400 autopilot controller, MS-560 mode selector, RI- 553 remote instrument controller and the DC-550 display controller. Information from these sources is processed and integrated into flight director commands and autopilot servo commands. Flight director commands appear on the EADI display and can be viewed in single cue or split-axis (cross pointer) presentation. Autopilot servo commands are issued to the rudder (yaw damper), aileron, elevator and pitch trim servos through the flight director. The system also contains pitch and roll comparators and various monitors.

In addition, the IC-500 interfaces with

  • VHF NAV radios,
  • DME,
  • ADF,
  • Radio Altimeters
  • optional FMS equipment
  • angle-of-attack (AOA) system.

EFIS Control

The DC-550 display controller provides control of the EFIS displays.

  • NAV and FMS buttons select
  • NAV 1,
  • NAV 2 or
  • FMS data presentation.

The GSPD/TTG button selects display of:

  • DME
  • FMS ground speed or
  • time to go.

The ET button selects, starts, stops and resets an elapsed timer.

The SC/CP button selects single cue or cross-pointer flight director command presentation.

The FULL/MAP button selects full or map (arc) compass display on the EHSI.

The MAP RNG button selects range in the map mode. The FMS flight plan can be displayed on the EHSI in the map mode if the EFIS is displaying FMS navigation information. The bearing pointer knobs can select the bearing pointers to OFF, NAV 1, NAV 2, ADF 1, ADF 2, and if the EFIS is displaying FMS data, the FMS waypoint. If only one ADF is installed, it will be displayed as both ADF 1 and ADF 2. The ADI and HSI dim knobs dim the respective displays. If either knob is turned to full dim, the opposite display will show the composite mode,
functioning as both ADI and HSI. The DH/TST knob is concentric inside the ADI dim knob. Rotating DH/TST knob sets the radar altitude decision height, and pressing it will test the EFIS display warnings.

Weight & Balance

Max Ramp Weight: 10.800 lbs
Max Take Off Weight: 10.700 lbs
Max Landing Weight: 9.900 lbs
Max Zero Fuel Weight: 8.400 lbs
Standard Empty Weight: 6.670 lbs
Useful Load: 4.030 lbs
Useful Fuel Capacity: 3.220 lbs