Lear 28

H o t r o d   o f   t h e   F l e e t

Lear 28 at Cabo



15,500 lbs
15,000 lbs
14,300 lbs
Zero Fuel
11,000 lbs
Basic Operating Weight 
  9,200 lbs


Vmo / Mmo
     SL to 14,000 msl
     Above 14,000 msl
     Auto Pilot & Mach Trim Inop
     Stick Puller Inop
     Boundry Layer Energizer Missing
IAS / Mach
306 / 0.82 Mach
359 / 0.82 Mach
0.74 Mach
0.74 Mach
0.78 Mach
Vmin / Above FL 450
0.65 Mach
200 kts
265 kts
     08 Deg
     20 Deg
     40 Deg
200 kts
190 kts
150 kts
  91 kts
  97 kts
Nosewheel Steering
  45 kts
Max Demonstrated Crosswind Component
   27 kts
Nosewheel Steering / more than one of RH 3 
    Anti Skid Generators inop
10 kts

Max Altitude
     Takeoff & Landing
51,000 ft
10,000 ft
Max Tailwind Component T.O. & Land
10 kts
Demonstrated Crosswind
 27 kts
Max Runway Clutter
0.75 inch
Pressurization Limits
9.7 Psid
Minimum Fuel / Takeoff
600 lbs / Tank
Temperature Limits
+ 50 C  to - 54 C
Load Factor
     Flaps Up
     Flaps Extended
+ 3.0 G to - 1.0 G
+ 2.0 G to - 0.0 G
Yaw Damper
2 Required
Max Altitude / Auto Pilot & Yaw Damper Inop
20,000 ft
Stall Warnings
2 Required
Generator Amps
     Below 60 deg F
     Above FL 450
300 amps
400 amps
200 amps


    The Lear 28 fuel system differs from the other 20 series in that it has no tip tanks, and a much larger fuselage tank.  The 28 also has 3 transfer mechanisms, and 4 options as to how to transfer the fuselage fuel to the wings.  As you can see, the Lear 28 does not have as much fuel as the other 20 Series airplanes, except for the 24 E, therefore, don't expect the same range.  Figure on the classic 2000 lbs of fuel the first hour, then 1300 lbs the second hour.  You then have about  1300 lbs of fuel left.  If you intend to land with any reasonable reserve, figure on 2 hours 15 minutes VFR, and 1 hour 30 minutes IFR.  If you stretch it farther than this and sooner or later you will wish you could find a tanker!      The picture at the beginning of this study guide was taken at Cabo San Lucas in Baja Mexico.  The last leg was Burbank California to Cabo, and that was about all the range we could muster without being stupid about it.

Lear 28 Fuel Panel

The fuel Transfer Methods

Fuselage Fuel gravity flows into wings slowly.  The last 194 lbs will not gravity transfer.
Normal Transfer
Left Fuselage Tank pump transfers fuel to both wings.  Crossflow Valve opens automatically.
Aux Transfer
Right Fuselage Tank pump transfers fuel to both wings.  Crossflow Valve opens automatically.
Rapid Transfer
Both Fuselage Tank Pumps operate, transferring fuel to each wing.  Crossflow valve is closed

Note:  Remember to transfer the fuselage fuel early.  You can have major center of gravity problems if you don't.  At low altitudes, you may not be able to transfer fuel as fast as the engines will burn it out of the wings.  If you are looking for a way to appear very stupid, and possibly run out of gas with fuel aboard, this is a good place to start!  The Xfer / Fill Switch ( 2nd from the lower left in the photo ) can easily be placed in the "Fill" position accidentally due to it's placement and poor design. Be sure and verify that it is actually in the "Off" position, as opposed to selecting "Fill" by mistake.  If you do screw this one up, your first sign may be the low fuel lights.  If this does happen, immediately select both normal and aux transfer.  This is the only way that the system has any chance of getting fuel to the wings as fast as the engines on this airplane will consume it at low altitude.  If anything is going to bite you in the ass on this airplane, it will be the fuel system.

    The Lear 28 hydraulic system is the same as on the other 20 series Lear Jets.  The fluid is 5606, 1.9 gallons in the reservoir, and 6.6 gallons in the entire system.  You have 2 engine driven pumps, one electric hydraulic pump, and an emergency air bottle.  The Gear, inboard main gear doors, flaps, spoilers and brakes are powered by the hydraulic system.  The emergency air will lower the landing gear, and provide 10 brake applications.   Anti skid and differential braking are not available when emergency air is used.

Accumulator & Pressure Gauge

    The engine driven hydraulic pumps can not use the last 0.4 gallons of fluid in the reservoir.  The electric hydraulic pump can use all the fluid.  The last 0.4 gallons should extend the gear, flaps and give you 10 brake applications through the use of the electric hydraulic pump.  This pump has a duty cycle limit of 3 minutes on, and 20 minutes off.  Leave it off when you are not operating or about to operate something with it.  During a normal flight, you will use it to set the parking brake, then leave it off for the rest of the flight.

Lear Jet Hydraulic System

Hydraulic Failure

Landing Gear
 Aux Hyd Pump or Emergency Air Bottle
Aux Hydraulic Pump or Vref + 20 kts Flaps Up Landing
Add 30% to Landing Distance  ***
Use of spoilers with Aux Hydraulic Pump Not Recommended when airborne
Later model Lears have a check valve preventing spoiler use with Aux Hyd Pump
Aux Hydraulic Pump or Emergency Air Bottle
No Anti Skid / No Differential Braking

*** Note:  The 30% landing distance adjustment addresses flaps only.  The lack of spoilers and anti skid in addition to the flaps up landing will result in a landing distance of between 1.7 and 2.0 times the normal landing distance.

    The Lear 28 has a basic late model Lear 25 electrical system.  You have 2 batteries, two Starter / Generators, two main electrical busses, two essential busses, and a bunch of circuit breakers and current limiters to tie them all together.  On the Lear 28, you must pull both the main bus tie and essential bus tie circuit breakers to perform a valid current limiter check.  Current limiters are not generally as much of a problem on the 20 series airplanes, as the generators will usually not produce enough current to blow the current limiters at idle rpm.  You can, however, blow one if you start with the freon system or aux heat on.  Those systems will turn off during engine cranking, but come back on when you put the first generator online.  This is when the current limiter blows.  Cranking current goes through the start relay, not the current limiter.  The current limiter ( 275 amp Fuse ) blows if the batteries are drawing more than the current limiter can handle while charging the batteries after the first engine start.  The 20 series Lear Jet electrical systems are highly reliable.  Don't expect a whole lot of trouble.

Lear Jet Electrical


    The Lear 28 has a simple environmental system.  Bleed air from the 8th stage of the engine compressors is routed through a heat exchanger and a flow control valve into the cabin.  Temperature is regulated by a valve that controls how much ambient air is allowed to flow across the heat exchanger.  The temperature control valve is 28 volt DC electric.  It operates in Automatic or manual modes, both being electric.
    If the cabin altitude exceeds 9,500 feet MSL, the emergency bleed valves open, bypassing the flow control valve and heat exchanger, routing raw bleed air into the cabin.
    Pressurization is controlled in the automatic mode, or with the manual system, or "Cherry Picker".  The automatic system requires DC electrical power, and the manual requires a light touch from the operator, as it is very sensitive.
    Above 11,000 foot cabin altitude, the outflow valve should close because of the cabin altitude limiter.  The system vents cabin pressure to the normal and safety outflow valves, causing them to close.

Lear Jet Environmental System


    The Lear 28 is powered by the CJ-610-8a engine.  Sea Level thrust is 2,950 lbs.  This engine design is almost older than Moses, and is as technologically mature as an engine is going to get.  Kind of like the 327 Chevy, time tested.  One thing to watch real close!  Don't shut off the engine anti ice without having the ignition on, and the rpm back to 95% or less.  If you do, the engine may flame out.  This problem usually happens above 15,000 feet.  Nobody from Lear or G.E. admits it, but the engine may flame out due to a pressure spike when the anti ice valve closes.  If you use the above procedure, you should have no problem.  Obey the 0.65 Mach Minimum Speed above FL 450.  Flameout may occur if you don't.

CJ-610-8A Engine
Oil Press Oil Temp
910 C /  2 Sec
854 C /  5 Sec
782 C / 10 Sec
175 psi
- 40 C Type 2 
- 54 C / Type 1
101.2 %
735 C / 5 Minutes
61 - 70 psi
185 C
Max Continuous
100.0 %
724 C
5 to 60 psi
185 C
  98.0 %
185 C

Note:  The 61 psi to 70 psi oil pressure limit is only for 12 minutes above 95 % rpm.  If you start both engines at the ramp, the oil should be warm enough.  Idle for 3 minutes if the temp is below - 25 deg C.  This also warms the hydraulic system.
Flight Profiles

    Here are some basic flight profiles that I have used over the years.  They are not the only way to fly the airplane, but have worked for me since I started giving training and checkrides in the Lear a little over 20 years ago.  In the event of a difference between this and the Aircraft Flight Manual, the flight manual is the document to follow.

Steep Turns

1.  Enter at 250 KTS indicated AIRSPEED.
2.  Bank aircraft 45 deg.  As you pass 30 deg of bank, pitch up 2 deg.  Add power to maintain AIRSPEED.
3.  Lead roll out by 15 deg.  Passing 30 deg bank, pitch down 2 deg  to maintain  altitude.
4.  Maintain 250 KTS and assigned heading.

Stall - Cruise Configuration

1.    Compute Vref & set AIRSPEED bugs.
2.    Maintain assigned altitude and set power to Idle.
3.    Trim for level flight until passing 150 KTS.  Maintain altitude with necessary back pressure.
4.    At stick shaker or stall warning lights,  throttles to " MAX POWER "
5.    Call " MAX  POWER Flaps Approach.
6     Reduce pitch ONLY to the extent necessary to eliminate symptoms of the stall.
7.    Reestablish assigned altitude.
8.    At Vref + 30 KTS, call " Flaps Up, After Takeoff Checklist.  "
9.    Maintain AIRSPEED and altitude as directed.

Stall - Takeoff Configuration

1.  Compute Vref, set AIRSPEED bugs & select flaps 20.
2.  Maintain assigned altitude and set power to 65% N1.
3.  Trim for level flight until passing 150 KTS.
4.  Maintain altitude with necessary back pressure.
5.  At stick shaker or stall lights, advance throttles & call " MAX POWER ".
6.  Reduce pitch ONLY to the extent necessary to eliminate symptoms of the stall.
7.  Reestablish assigned altitude.
8.  At Vref + 30 KTS, call " Flaps Up, After Takeoff Checklist.  "
9.  Maintain AIRSPEED and altitude as directed.

Stall - Landing Configuration

1.    Slow to flap speed, set 80% N1 & Set bug to Vref.
2.    Maintain assigned heading & altitude.
3.    Below 200 KTS, " Flaps 8 deg".
4.    Below 190 KTS, " Flaps 20 deg".
5.    Below 200 KTS, " Gear Down Landing Check ".
6.    Below 150 KTS, " Full flaps. " trim to Vref. Establish a 400-700 feet/min sink rate at Vref.
7.    Level off at designated altitude  W I T H O U T increase in power
8.    Maintain altitude until  first indication of a stall. (Shaker or stall lights)
9.    Apply MAX power lower nose only as much as required to eliminate the stall warning.
       At Vref minus 10 KTS   M I N I M U M  speed, call for " Flaps 20 deg", and increase the
        pitch attitude to 10 deg nose up at about 1 deg / sec.
10.  When VSI & Altimeter indicate positive rate of climb call " Positive rate, Gear Up ".
11.  Establish 7.5 deg nose up attitude.
12.  At Vref + 30 KTS, Call " Flaps Up, After Takeoff Checklist ".
13.  Return to entry heading and altitude or as directed.

ILS Approach - Two Engines

1.    Intercept LOC at 140-160 KTS and Flaps 20 deg.
2.    One dot prior to intercepting Glide Slope, call " Gear Down Landing Check ".
3.    When ON the glidepath, call " Full Flaps ".
4.    Establish Vref to Vref + 5 KTS & track LOC & GS until Minimums.  Land or Missed Approach as appropriate.

ILS Approach - One Engine

 1.  Intercept LOC at 140-160 KTS and Flaps 8 deg.
 2.  One dot prior to intercepting Glide Slope, call " Gear Down Landing Check ".
 3.  When ON the glidepath, call "Flaps 20 deg".
 4.  Establish Vref + 20 KTS & track LOC & GS
 5.  At 100-150 Ft AGL, Full flaps, power idle & land.

Non Precision Approach - One or Two Engines

1.    Intercept Final Approach Course at 140 KTS and Flaps 20 deg.
2.    Crossing Final Approach Fix, call " Gear Down Landing Check ".
3.    Descend to and maintain MDA until Field in Sight or MAP is initiated. ( As Appropriate ).
4.    If Landing is to be made, call " Full Flaps " when intercepting a glidepath appropriate for a
       normal landing.  For one engine INOP, Vref + 20 KTS until 100 feet AGL, then " Full
       Flaps" so as to descend thru 50 ft AGL at Vref as in a normal landing.

No Flap Approach

1.  Vref + 30 KTS until established on Final Approach.
2.  Vref + 20 KTS on final.
3.  Approach angle NORMAL.  A flat approach will usually result in a longer landing roll.

Go Around or Missed Approach

1.  "Max Power", Rotate to 10 deg, " Flaps 20 deg".
2.  Positive Rate of Climb, " Gear Up ", Vref + 30, " Flaps up, After Takeoff Checklist ".
3.  Climb at 200 KTS.
4.  Engine Failure or Fire Checklist if Appropriate.


1.  Set V2 on Capt. Airspeed & V1 on Co-Pilots Airspeed.
2.  At V 1, BOTH hands on Yoke.
3.  Vr, Rotate to 15 deg ( 2 eng ) 12 deg ( 1 eng ).
4.  Climb at 15 deg pitch, ( 2 eng ) or V 2 ( 1 eng ).
5.  At 400 ft & V2+30 KTS, "Flaps Up After T.O. Check ".
6.  Engine Failure or Fire Checklist if Appropriate.
7.  Climb  200 KTS to 3000 AGL then 250 Kts.

Rejected Takeoff

1.  Proceed as in normal takeoff until malfunction dictates that the takeoff be rejected.
2.  Capt. calls "Abort" (Co-Pilot may call Abort if Capt elects to delegate that authority).
3.  Thrust levers to idle
4.  Spoilers extend.
5.  Wheel brakes as necessary.
6.  Thrust Reverse OR Dragchute deploy.  (Never Both!)
7.  If another takeoff is contemplated consider brake energy & appropriate turnaround time.

Emergency Descent

 1.    Oxygen masks on within 5 sec of cabin pressure loss.
 2.    Check passenger oxygen masks deployed.
 3.     Select Oxygen mask microphone.
 4.    Ignition ON.
 5.    Thrust levers to idle.
 6.    Spoilers and Landing Gear, Extend.
 7.    Auto Pilot OFF.
 8.    Initiate 45 deg bank if desired.
 9.    Vmo/Mmo minus 10 kts to 14,000 or MEA as required.
10.  Clean up & proceed to nearest suitable airport if appropriate.  Condition of aircraft or
        reduced range due to low altitude may make flight to original destination unwise.