P.O. BOX 790490 • SAN ANTONIO, TEXAS 78279-0490 • (210) 824-9421

SUBJECT: REVISION A-29 TO SA226-T AFM

TO: ALL OPERATORS AND AFM MANAGERS OF THE SA226-T

1. Attached is Revision A-29 to Sections i and III of your AFM.

2. File this transmittal letter in your AFM binder at the location most convenient for you.
P.O. Box 790490 • San Antonio, Texas 78279–0490 • (210) 824–9421
FAA Approved: May 6, 1977 iii

SWEARINGEN MERLIN SA226-T

FAA APPROVED FLIGHT MANUAL

REISSUE A

S/N T–201 AND SUBSEQUENT

LIST OF EFFECTIVE PAGES

Page Date Page Date

SECTION I

Page Date Page Date

SECTION II

Page Date Page Date

II-i .......................................... December 7, 2007

II-ii ........................................... October 16, 1997

II-1 ............................................... June 28, 1976

II-2 ............................................... June 28, 1976

II-3 ............................................... June 28, 1976

II-4 ................................................April 28, 2000

II-5 ..................................... September 14, 1995

II-6 ..................................... September 14, 1995

II-7 ............................................. March 29, 1994

II-8 .......................................... January 14, 1982

II-9 ...................................... November 29, 2005

II-10 .................................... November 29, 2005

II-10a .................................. November 29, 2005

II-10b .................................. November 29, 2005

II-11 ................................................ June 8, 1981

II-12 ........................................ October 30, 1985

II-13 ............................................... June 2, 2000

II-14 ............................................... June 2, 2000

II-15 ........................................ October 19, 1981

II-16 ............................................. June 28, 1976

II-17 ............................................. June 28, 1976

II-18 ................................... September 14, 1995

II-19 ................................... September 14, 1995

II-20 ................................... September 14, 1995

II-21 .................................... December 14, 1978

II-22 ........................................ October 16, 1997

II-23 ...................................... December 7, 2007

II-23A .................................... December 7, 2007

II-23B .................................... December 7, 2007

II-24 ............................................. June 28, 1976

II-25 ................................... September 14, 1995

II-25a ................................. September 14, 1995

II-25b ................................. September 14, 1995

II-26 ............................................. June 28, 1976

II-27 ........................................ October 25, 1977

II-28 ........................................ January 14, 1982

II-29 ........................................ January 14, 1982

II-30 ............................................. June 28, 1976

II-31 ............................................. June 28, 1976

II-32 ............................................. June 28, 1976

 i Title .......................................... June 28, 1976

 ii .................................................. June 28, 1976

 iii ........................................ November 14, 2014

 iv ........................................ November 14, 2014

 v .................................................... June 3, 1980

 vi ............................................ January 28, 1982

 vii ...................................... September 14, 1995

 viii ........................................ December 7, 2007

 ix ........................................ November 14, 2014

 x ................................................... May 28, 2008

I-i ........................................... December 7, 2007

I-ii ............................................ October 16, 1997

I-1 ....................................... December 14, 1978

I-2 ................................................ June 28, 1976

I-3 ......................................... December 7, 2007

I-4 ....................................... December 14, 1978

I-5 ......................................... December 8, 1980

I-6 ................................................ March 5, 1981

I-7 ........................................... October 16, 1997

I-8 .................................................. June 2, 2000

I-9 .................................................. June 2, 2000

I-10 ................................................ June 2, 2000

I-11 .......................................... January 31, 2013

I-12 ............................................ March 29, 1994

I-13 .............................................. June 28, 1976

I-14 .............................................. June 28, 1976

I-15 .............................................. June 28, 1976

I-16 .............................................. June 28, 1976

FAA Approved: December 18, 1981

Revised: November 14, 2014
iv FAA Approved: May 6, 1977

SWEARINGEN MERLIN SA226-T

FAA APPROVED FLIGHT MANUAL

REISSUE A

S/N T–201 AND SUBSEQUENT

LIST OF EFFECTIVE PAGES (continued)

SECTION III

Page Date Page Date

SECTION IV

Page Date Page Date

FAA Approved: December 19, 1978

Revised: November 14, 2014

III-12 ................................... November 14, 2014

III-13 ................................... November 14, 2014

III-14 ................................... November 14, 2014

III-15 ................................... November 14, 2014

III-16 ................................... November 14, 2014

III-16A ................................. November 14, 2014

III-16B ................................. November 14, 2014

III-17 ................................... November 14, 2014

III-18 ................................... November 14, 2014

III-19 ................................... November 14, 2014

III-20 ................................... November 14, 2014

III-21 ................................... November 14, 2014

III-22 ................................... November 14, 2014

III-23 ................................... November 14, 2014

III-24 ................................... November 14, 2014

III-25 ................................... November 14, 2014

III-26 ................................... November 14, 2014

III-i ....................................... November 14, 2014

III-ii ...................................... November 14, 2014

III-1 ................................................May 11, 1999

III-1A ................................... November 14, 2014

III-1B ................................... November 14, 2014

III-2 ................................................May 11, 1999

III-3 ................................................May 11, 1999

III-4 ..................................... November 14, 2014

III-5 ..................................... November 14, 2014

III-6 ..................................... November 14, 2014

III-7 ..................................... November 14, 2014

III-8 ..................................... November 14, 2014

III-9 ..................................... November 14, 2014

III-10 ................................... November 14, 2014

III-11 .................................... November 14, 2014

III-11A ................................. November 14, 2014

III-11B ................................. November 14, 2014

IV-i ............................................... June 28, 1976

IV-ii............................................... June 28, 1976

IV-1 .............................................. June 28, 1976

IV-2 .............................................. June 28, 1976

IV-3 .............................................. June 28, 1976

IV-4 .............................................. June 28, 1976

IV-5 .............................................. June 28, 1976

IV-6 .............................................. June 28, 1976

IV-7 .............................................. June 28, 1976

IV-8 .............................................. June 28, 1976

IV-9 .............................................. June 28, 1976

IV-10 ............................................ June 28, 1976

IV-11 ............................................ June 28, 1976

IV-12 ............................................ June 28, 1976

IV-13 ............................................ June 28, 1976

IV-14 ............................................ June 28, 1976

IV-15 ............................................ June 28, 1976

IV-16 ............................................ June 28, 1976

IV-17 ............................................ June 28, 1976

IV-18 ............................................ June 28, 1976

IV-19 ............................................ June 28, 1976

IV-20 ................................... December 19, 1978

IV-21 .........................................August 10, 1977

IV-22 .........................................August 10, 1977

IV-23 ............................................ June 28, 1976

IV-24 ............................................ June 28, 1976

IV-25 ............................................ June 28, 1976

IV-26 ............................................ June 28, 1976

IV-27 ............................................ June 28, 1976

IV-28 ............................................ June 28, 1976

IV-29 ............................................ June 28, 1976

IV-30 ............................................ June 28, 1976

IV-31 ............................................ June 28, 1976

IV-32 ............................................ June 28, 1976

IV-33 ............................................ June 28, 1976

IV-34 ............................................ June 28, 1976

x FAA Approved: May 6, 1977

SWEARINGEN MERLIN SA226-T

INTENTIONALLY LEFT BLANK

FAA Approved: May 28, 2008
FAA Approved: June 28, 1976 III–i

Revised: November 14, 2014

SWEARINGEN MERLIN 226-T

CONTENTS

Item Page

Introduction .....................................................................................................................................III–1

Engine Fire on Ground ................................................................................................................ III–1A

Engine Fire During Flight ............................................................................................................. III–1A

Out-of-Trim Warning .................................................................................................................... III–1B

Engine Failure During Takeoff – Takeoff Aborted ........................................................................ III–1B

Engine Failure During Takeoff – Takeoff Continued at or Above VR ..............................................III–2

Engine Failure During Flight ...........................................................................................................III–3

Double Engine Failure (Restarts/Relights Unsuccessful) ...............................................................III–3

Engine-Propeller Uncoupling .......................................................................................................... III-4

Airstart Procedure...........................................................................................................................III–4

Aborted Airstart (Due to No Combustion) .......................................................................................III–5 

Single Engine Landing....................................................................................................................III–5

Single Engine Go-Around ...............................................................................................................III–6

Chip Light On Prior to Takeoff ........................................................................................................III–6

Chip Light On During Flight ............................................................................................................III–7

Boost Pump Failure ........................................................................................................................III–7

Fuel Transfer Pump Warning Light On ...........................................................................................III–7

Power Plant Control Malfunction ....................................................................................................III–7

No Response to Power Lever Movement ....................................................................................... III-8

Cabin Pressurization Malfunctions

 Low Pressure Malfunction .....................................................................................................III–8

 High Pressure Malfunction ....................................................................................................III–8

 Excessive Rate of Pressurization ..........................................................................................III–9

Emergency Descent Procedure......................................................................................................III–9

Cabin Door Warning Light On ......................................................................................................III–10

Smoke in Cabin ............................................................................................................................III–10

Wheelwell and Wing Overheat Light On

 Steady Light .........................................................................................................................III–11

 Flashing Light ......................................................................................................................III–11

Hydraulic System Failure..............................................................................................................III–12

Landing Gear Emergency Extension ............................................................................................III–12

Gear Up Landings ..................................................................................................................... III–12A

Electrical System Failures

 Excessive Ammeter Indication .......................................................................................... III–12B

 Battery Fault Light On ..........................................................................................................III–13

 Battery Overheat Warning Light On During Flight ...............................................................III–15

 Generator Inoperative – Ammeter Reading Zero ................................................................III–15

 Circuit Breaker Tripped ........................................................................................................III–15

 Inverter Inoperative ..............................................................................................................III–15

 Electrical Bus Failure ...........................................................................................................III–16

 Electrical Smoke or Fire ......................................................................................................III–16

 Total Electrical Failure .........................................................................................................III–16
III–ii FAA Approved: June 28, 1976

Revised: November 14, 2014

SWEARINGEN MERLIN 226-T

CONTENTS (continued)

Item Page

Nose Wheel Steering Malfunctions

 Side Control Wheel System (when installed) ......................................................................III–17

 Variable Authority Nose Wheel Steering System (when installed in

 accordance with SB 226 32-032) .....................................................................................III–17

 Variable Authority Nose Wheel Steering System (On those aircraft which 

 have been modifi ed in accordance with Service Bulletin 32-037) ................................. III–17A

 Electrical Malfunction ............................................................................................... III–17A

 Hydraulic Malfunction .............................................................................................. III–17A

 Nose Steer FAIL Light ON ........................................................................................III-17B

Stabilizer Trim Malfunctions

 Pilot's Trim System Inoperative ...........................................................................................III–18

 Copilot's Trim System Inoperative .......................................................................................III–18

 Both Pilot's and Copilot's Trim System Inoperative .............................................................III–18

 Go-Around with Stabilizer Trim Inoperative .........................................................................III–19

 Stabilizer Trim System Runaway .........................................................................................III–19

Stability Augmentation and Stall Avoidance System (SAS2) Malfunctions

 SAS Fault Light On (Steady or Flashing) ............................................................................III–20 

SAS Malfunction – Nose Down ....................................................................................................III–21

 Aural Stall Warning at Speeds Well in Excess of Normal Stall Warning Speeds ................III–22

Yaw Damper Malfunctions

 Power Failure ......................................................................................................................III–22

 Electrical Servo Runaway ....................................................................................................III–23

Instrument Static Pressure Malfunction ........................................................................................III–23

Emergency Exit ............................................................................................................................III–23

Weather Conditions Conducive to Severe In-fl ight Icing ..............................................................III–24

Procedures for Exiting the Severe Icing Environment ..................................................................III–24

Inadvertent Icing Encounter..........................................................................................................III–25

Blank Page ................................................................................................................................... III-26
III–1

SWEARINGEN MERLIN 226-T

FAA Approved: June 28, 1976

Revised: May 11, 1999

INTRODUCTION

Section 3 of this manual covers emergencies that might occur during ground or fl ight operation and the 

recommended procedures for correcting the situation. The IMMEDIATE ACTION items, which must 

be performed fi rst, are in BOLD CAPITAL LETTERS with the remaining steps (clean up procedures) 

following. Expanded procedures are covered in this section. Procedures identifi ed by an asterisk 

are those recommended to be accomplished by a copilot during two pilot operations. The emergency 

procedures in this section have been FAA approved. 

NOTE

• Overcoming emergencies successfully depends upon the pilot’s sound judgement and thorough knowledge of the aircraft 

systems and equipment. 

• In case of emergency:

 1. Maintain aircraft control. 

 2. Analyze the situation. Then take proper action to correct it. 

 3. If the diffi culty has occurred during fl ight, land as soon as conditions permit.
III–2 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

FAA Approved: June 28, 1976

Revised: November 14, 2014

ENGINE FAILURE DURING TAKEOFF – TAKEOFF CONTINUED

AT OR ABOVE VR

WARNING

IN THE EVENT OF AN ENGINE FAILURE OR POWER LOSS, 

THE ENGINE NEGATIVE TORQUE SYSTEM (NTS) ONLY 

PROVIDES PARTIAL DRAG REDUCTION BUT NOT TO THE 

EXTENT OF A FULLY FEATHERED PROPELLER. 

PILOT MUST TAKE ACTION TO FULLY FEATHER THE PROPELLER (ON THE AFFECTED ENGINE) TO REDUCE PROPELLER DRAG.

1. POWER LEVER (operating engine) ................................................ SET TAKEOFF POWER

NOTE

Set 923oC ITT or 2206 foot-pound torque, whichever occurs 

fi rst. If the 2363 foot-pound torque limit is not being developed 

and bleed air is on, increased power may be obtained by selecting 

bleed air off.

2. LANDING GEAR .........................................................................RETRACT AFTER LIFTOFF

WARNING

IF THE ENGINE FAILURE IS ACCOMPANIED BY A LEFT ESSENTIAL BUS FAILURE (AS INDICATED BY LOSS OF POWER 

TO THE GEAR POSITION INDICATOR) THE LANDING GEAR 

WILL NOT RETRACT UNTIL THE LANDING GEAR CONTROL 

ESSENTIAL BUS POWER TRANSFER IS MOVED TO THE RIGHT 

BUS POSITION.

3. ENGINE STOP AND FEATHER CONTROL (failed engine) .......................................... PULL

 4. AIRSPEED ...............................................SINGLE ENGINE BEST RATE OF CLIMB SPEED

(SEE FIGURE 4–15C) 

 5. Engine Clean Up Procedure (failed engine)

 a. Fuel shutoff switch ............................................................................................... CLOSED 

 b. Hydraulic shutoff switch ....................................................................................... CLOSED 

 c. Fuel boost pump switch ...............................................................................................OFF 

 d. Generator switch ..........................................................................................................OFF

 e. Bleed air switch ............................................................................................................OFF 

 6. Power Lever (operating engine) .......................................................................AS REQUIRED

 7. Trim ...................................................................................................................AS REQUIRED

 8. Generator (operating engine) ................................................................ 300 AMPS MAXIMUM 

 9. Propeller Synchronizer ......................................................................... TAKEOFF – LANDING
III–3

SWEARINGEN MERLIN 226-T

ENGINE FAILURE DURING FLIGHT

WARNING

IN THE EVENT OF AN ENGINE FAILURE OR POWER LOSS, 

THE ENGINE NEGATIVE TORQUE SYSTEM (NTS) ONLY 

PROVIDES PARTIAL DRAG REDUCTION BUT NOT TO THE 

EXTENT OF A FULLY FEATHERED PROPELLER. 

PILOT MUST TAKE ACTION TO FULLY FEATHER THE PROPELLER (ON THE AFFECTED ENGINE) TO REDUCE PROPELLER DRAG.

 1. ENGINE STOP AND FEATHER CONTROL (failed engine) .......................................... PULL 

 2. Engine Clean Up Procedure (failed engine)

 a. Fuel shutoff switch ................................................................................................CLOSED 

 b. Hydraulic shutoff switch ........................................................................................CLOSED 

 c. Fuel boost pump switch ............................................................................................... OFF 

 d. Generator switch .......................................................................................................... OFF 

 e. Bleed air switch ........................................................................................................... .OFF 

 3. Power Lever (operating engine) .......................................................................AS REQUIRED 

 4. Bleed Air (operating engine) .............................................................................AS REQUIRED

NOTE

If the torque limit is not being developed and bleed air is on, 

increased power may be obtained by selecting bleed air off.

 5. Trim ...................................................................................................................AS REQUIRED

 6. Generator (operating engine) ................................................................ 300 AMPS MAXIMUM 

 7. Propeller Synchronizer ......................................................................... TAKEOFF – LANDING

DOUBLE ENGINE FAILURE (RESTARTS/RELIGHTS UNSUCCESSFUL)

1. AIRSPEED .................................................................... MAINTAIN BEST GLIDE AIRSPEED

GLIDE AIRSPEED

 WEIGHT (POUNDS) 12,000 10,000 8,500 

 AIRSPEED (KIAS) 148 136 126

NOTE

• Best glide airspeed is approximately 1.5 V/VS on the SAS 

indicator.

• Glide ratio at best glide airspeed is approximately 10:1 

(2NM/1,000 FT AGL). 

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–4 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

DOUBLE ENGINE FAILURE (RESTARTS/RELIGHTS UNSUCCESSFUL) (continued)

 2. GEAR ...................................................................................................................................UP

 3. FLAPS ..................................................................................................................................UP

 4. Complete Engine Failure During Flight Checklist

 Plan for emergency gear extension and a zero fl ap landing. If altitude above ground level 

(AGL) permits, unfeathering one engine may provide suffi cient hydraulic pressure to operate 

the fl aps.

ENGINE - PROPELLER UNCOUPLING

WARNING 

• IN THE EVENT OF ENGINE FAILURE IN CONJUNCTION 

WITH ENGINE UNCOUPLING, REDUCE WINDMILLING 

DRAG AS FOLLOWS:

• IF AN UNCOUPLING EVENT OCCURS WHERE THE ENGINE IS OPERATING AND THE PROPELLER IS STOPPED 

AND FEATHERED, RETARDING THE POWER LEVER 

TO FLIGHT IDLE MAY RESULT IN UNFEATHERING AND 

SUBSEQUENT ROTATION OF THE PROPELLER. IF THIS 

OCCURS, ADVANCE THE POWER LEVER TO MAXIMUM 

POWER POSITION.

• IN THE EVENT OF AN ENGINE WITH AN NTS AND/OR 

FEATHER VALVE MALFUNCTION, SETTING THE ASSOCIATED POWER LEVERS FULL FORWARD WILL DRIVE THE 

PROPELLER BLADES TOWARD THE FEATHER POSITION 

YIELDING A LOWER WINDMILLING PROPELLER DRAG 

AND PROPELLER SHAFT SPEED.

AIRSTART PROCEDURE

CAUTION

IF AN ENGINE HAS BEEN SHUT DOWN BECAUSE OF 

AN OBVIOUS FAILURE, AS INDICATED BY THE ENGINE 

INSTRUMENTS OR EXCESSIVE VIBRATION, AN AIRSTART 

SHOULD NOT BE MADE.

NOTE

Satisfactory airstarts have been demonstrated up to 20,000 feet 

pressure altitude with the fuel boost pumps operating and up to 

12,000 feet pressure altitude without the boost pumps operating. 

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–5

SWEARINGEN MERLIN 226-T

AIRSTART PROCEDURE (continued)

1. Speed Lever ........................................... 96% RPM (THE 96% RPM SPEED LEVER POSITION 

CAN BE OBTAINED BY SETTING THE OPERATING ENGINE SPEED AT 96% RPM AND ALIGNING BOTH SPEED 

LEVERS.) 

 2. Power Lever .................................APPROXIMATELY 1/4 INCH FORWARD OF FLIGHT IDLE

 3. ITT ........................................................................................... BELOW 300oC (IF FEASIBLE)

 4. RPM ...................................................................................................................10% OR LESS

 5. Altitude ...............................................................................................20,000 FEET MAXIMUM

 6. Airspeed ............................................................................................... 100 KIAS TO 180 KIAS 

 7. Engine Stop and Feather Control ........................................................................... FORWARD 

 8. Fuel Shutoff Switch ......................................................................................................... OPEN 

 9. Hydraulic Shutoff Switch ................................................................................................. OPEN 

 10. Fuel Boost Pump Switch ...................................................................................................... ON 

 11. Generator Switch ............................................................................................................... OFF 

 12. Bleed Air Switch ................................................................................................................. OFF 

 13. Engine Start Button ...............................................................................DEPRESS AND HOLD

 14. Propeller ..................................................................................... OBSERVE UNFEATHERING 

 15. Fuel Flow .................................................................................SHOULD START AT 10% RPM

 16. ITT ................................................. SHOULD INDICATE IGNITION AT 10% TO 20% RPM, IF 

IGNITION NOT INDICATED BY 25% RPM, ABORT START 

BY PRESSING STOP BUTTON AND PULLING ENGINE 

STOP AND FEATHER CONTROL

 17. Engine Start Button .........................RELEASE IMMEDIATELY WHEN ITT STARTS TO RISE. 

 18. Fuel and Oil Pressure .......................................................................................... GREEN ARC 

 19. Generator Switch .................................................................................................... RESET/ON 

 20. Bleed Air Switch ................................................................................................ NORMAL (ON)

ABORTED AIRSTART (DUE TO NO COMBUSTION)

 1. Engine Stop Button .................................................................................................. DEPRESS

 2. Engine Stop and Feather Control .....................................................................................PULL

 3. Altitude .................................................REDUCE BEFORE ATTEMPTING ANOTHER START

SINGLE ENGINE LANDING

WARNING

IN THE EVENT OF AN ENGINE FAILURE OR POWER LOSS, 

THE ENGINE NEGATIVE TORQUE SYSTEM (NTS) ONLY 

PROVIDES PARTIAL DRAG REDUCTION BUT NOT TO THE 

EXTENT OF A FULLY FEATHERED PROPELLER. 

PILOT MUST TAKE ACTION TO FULLY FEATHER THE PROPELLER (ON THE AFFECTED ENGINE) TO REDUCE PROPELLER DRAG.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–6 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

SINGLE ENGINE LANDING (continued)

Use normal procedures with the following exceptions:

 1. Fuel Crossfl ow Switch ................... OPEN (BALANCE FUEL WITHIN 500 POUNDS, THEN 

CLOSE)

 2. Electrical Load ................................................................TURN OFF NONESSENTIAL ITEMS

 3. Flaps ...................................DO NOT EXTEND BEYOND 1/2 UNTIL LANDING IS ASSURED

 4. Landing Gear .......................................................... EXTEND WHEN LANDING IS ASSURED

 5. Reverse Thrust .................................................................................................AS REQUIRED

CAUTION

REVERSE THRUST ON THE OPERATING ENGINE WILL 

CAUSE A YAWING MOMENT TOWARD THE OPERATING ENGINE WHICH IS PROPORTIONAL TO THE AMOUNT OF REVERSE THRUST APPLIED. ON WET OR ICY RUNWAYS, IT IS 

POSSIBLE TO APPLY MORE ASYMMETRIC REVERSE THRUST 

THAN CAN BE COUNTERACTED BY OPPOSITE BRAKE, RUDDER, AND NOSE WHEEL STEERING.

SINGLE ENGINE GO-AROUND

WARNING

IN THE EVENT OF AN ENGINE FAILURE OR POWER LOSS, 

THE ENGINE NEGATIVE TORQUE SYSTEM (NTS) ONLY 

PROVIDES PARTIAL DRAG REDUCTION BUT NOT TO THE 

EXTENT OF A FULLY FEATHERED PROPELLER. 

PILOT MUST TAKE ACTION TO FULLY FEATHER THE PROPELLER (ON THE AFFECTED ENGINE) TO REDUCE PROPELLER DRAG.

1. POWER ............................................................................................................AS REQUIRED

 2. LANDING GEAR ..................................................................................................... RETRACT

 3. FLAPS ........................................................................................RETRACT IN INCREMENTS

 4. AIRSPEED .............................................. SINGLE ENGINE BEST RATE-OF-CLIMB SPEED

(SEE FIGURE 4–15C)

 5. Bleed Air Switch ................................................................................................................. OFF

 6. Engine Anti-Ice ................................................................................................................... OFF

CHIP LIGHT ON PRIOR TO TAKEOFF

If the chip light illuminates prior to takeoff, the fl ight should be aborted and the cause of the 

warning determined.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–7

SWEARINGEN MERLIN 226-T

CHIP LIGHT ON DURING FLIGHT

If the chip light illuminates and engine operation appears to be normal, continue to the fi rst intended 

landing and determine cause. The affected engine should be monitored closely during fl ight.

If the chip light illuminates and engine operation does not appear to be normal, the affected engine 

should be shut down (Engine Failure During Flight Procedure) and a single engine landing acomplished.

BOOST PUMP FAILURE

 A In the event of a primary AC pump failure, either because of pump malfunction or an alternator failure, the system will automatically switch to the DC fuel pump. If this automatic change 

does not occur (as indicated by low fuel pressure) manual selection of the DC pump can be 

accomplished by placing the boost pump switch in the "DC" position. See Figure 1–1 for "no 

boost pumps required" fl ight envelope.

 B In the event of a boost pump failure, as indicated by low fuel pressure, the auxiliary boost 

pump should be selected. See Figure 1–1 for "no boost pumps required" fl ight envelope.

FUEL TRANSFER PUMP WARNING LIGHT ON

In the event that a transfer pump warning light illuminates with more that 75 pounds of fuel remaining 

in the affected tank, the auxiliary boost pump should be turned on. If the light remains illuminated, use 

the higher unusable fuel quantity of 75 pounds. (Reference Section II, Fuel System.)

CAUTION

WITH TRANSFER PUMPS OPERATIVE AND LESS THAN 

75 POUNDS OF FUEL IN THE AFFECTED TANK, THE 

TRANSFER PUMP WARNING LIGHT SERVES AS A LOW 

FUEL WARNING. A LANDING SHOULD BE MADE AS SOON 

AS PRACTICAL.

 A S/N T–201 through T–248. (Equipped with generators and alternators)

 B S/N T–249 and subsequent. (Equipped with generators – no alternators)

POWER PLANT CONTROL MALFUNCTION

In the event there is an indication of improper operation of a fuel control or propeller control, it is recommended that the affected engine be shut down and a single engine landing accomplished.

FAA Approved: June 28, 1976 

Revised: November 14, 2014
III–8 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

NO RESPONSE TO POWER LEVER MOVEMENT

If either engine (or both) exhibits a lack of response to the power lever after extended operation at 

high altitude with OAT below freezing, the cause may be ice blockage of the PT2 inlet sensor probe. 

In certain fl ight conditions, when engine anti-ice would not normally be ON, probe icing can occur 

even though visible moisture is not present. If lack of power lever response is observed, the following 

procedure should be accomplished:

 1. Ignition Switches ............................................................................................................. CONT

 2. Engine Heat Switch(es) ......................................................................ENGINE & PROP HEAT

This will introduce anti-icing air to the sensors (as well as the engine inlet) and normal power lever 

response should return within approximately 3 minutes.

After the condition has cleared and normal operation is observed, anti-ice and ignition can again be 

turned OFF.

 1. Engine Heat Switch(es) ....................................................................................AS REQUIRED

 2. Ignition Switches ..............................................................................................................AUTO

CABIN PRESSURIZATION MALFUNCTIONS

LOW PRESSURE MALFUNCTION

The cabin altitude warning light illuminates when the cabin pressure is equivalent to a pressure altitude between 10,000 feet and 12,000 feet. Check differential pressure and the controller setting. If 

the cabin pressure controller is not providing proper cabin pressure, change to manual operation. If 

the desired differential pressure still cannot be attained, an excessive leak is indicated and it may be 

necessary to descend or use oxygen.

HIGH PRESSURE MALFUNCTION

If the cabin differential pressure exceeds the normal limit of 7 psi, the cabin pressurization controller may have failed and allowed the outfl ow valve to close. Open the manual valve slightly, select 

MANUAL position on the cabin pressure selector, and regulate pressure manually. If manual control 

is ineffective, the safety valve should relieve excess cabin pressure at 7.25 psi. Prior to landing, the 

cabin pressure differential must be eliminated by use of the manual control or the following alternate 

procedure:

 1. Aircraft Altitude ....................................................................................... BELOW 12,000 FEET

 2. Bleed Air Switches ............................................................................................................. OFF

 3. Allow cabin to depressurize to less than 1 psi differential.

 4. Cabin Dump Switch ........................................................................................................DUMP

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–9

SWEARINGEN MERLIN 226-T

CABIN PRESSURIZATION MALFUNCTIONS (continued)

NOTE

If the cabin pressure is dumped when a signifi cant cabin pressure 

differential exists, the resulting sensation may be alarming and uncomfortable to passengers. Consequently, use of the dump valve 

normally should be restricted to situations where cabin pressure 

differential is less than 1 psi or when other methods of pressure 

differential control are ineffective.

 5. Bleed Air Switches ............................................................................................ NORMAL (ON)

 6. Proceed unpressurized to airport. Air conditioning will be available.

EXCESSIVE RATE OF PRESSURIZATION

If an excessive rate of pressurization is experienced and it cannot be controlled by the rate knob 

on the cabin pressurization controller or by the manual control knob, the following steps should be 

accomplished:

 1. Bleed Air Switches ............................................................................................................. OFF

 If Step 1 eliminated the excessive rate of pressurization, determine the source of the malfunction by turning the bleed air controls on individually. If the malfunction was caused by one of 

the bleed air control valves, leave the malfunctioning side off and continue pressurized fl ight 

using bleed air from one engine.

 If the pressure surge does not decrease:

 2. Cabin Dump Switch ........................................................................................................DUMP

NOTE

If the cabin pressure is dumped when a signifi cant cabin pressure 

differential exists, the resulting sensation may be alarming and uncomfortable to passengers. Consequently, use of the dump valve 

normally should be restricted to situations where cabin pressure 

differential is less than 1 psi or when other methods of pressure 

differential control are ineffective.

EMERGENCY DESCENT PROCEDURE

If cabin pressure is lost for any reason while at high altitude, execute the following procedure:

1. OXYGEN VALVE ................................................................................................................. ON

 2. PASSENGER AND CREW OXYGEN MASKS .................................................................DON

 3. Speed Levers ....................................................................................................................HIGH

 4. Power Levers .......................................................................................................FLIGHT IDLE

 5. Airspeed ................................................................................................. 176 KCAS MAXIMUM

 6. Landing Gear ................................................................................................................. DOWN

 7. Flaps ....................................................................................................................... ONE-HALF

 8. Altitude ..............................................................................................................AS REQUIRED

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–10 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

CABIN DOOR WARNING LIGHT ON

PRIOR TO TAKEOFF

 Takeoff should not be initiated.

IN FLIGHT

 1. Depressurize airplane.

 2. Descend as required.

 3. Land as soon as practical.

SMOKE IN CABIN

1. OXYGEN VALVE ................................................................................................................. ON

 2. CREW OXYGEN MASKS .................................................................................................DON

 3. Cabin Dump Switch ........................................................................................................DUMP

 4. Emergency Descent .........................................................................................AS REQUIRED

 5. Airspeed ................................................................................................. 176 KCAS MAXIMUM

 6. Landing Gear ..............................................................................................................EXTEND

 7. Fresh Air Fan ..........................................................................................................OVERRIDE

 8. Source of Smoke ................................................................................................. DETERMINE

 a. Electrical source

 • Eliminate source of smoke by following Electrical Smoke or Fire Procedure (see 

page III–15).

 b. Bleed air source

 (1) Determine which side is smoking.

 (2) Turn bleed air OFF on affected side.

 (3) If smoke continues, shut down the affected engine.

NOTE

If a failure occurs in the pneumatic or electrical system of the 

bleed air control valve, the engine may have to be shut down to 

stop the fl ow of bleed air.

FAA Approved: October 25, 1977

Revised: November 14, 2014
III–11

SWEARINGEN MERLIN 226-T

WHEELWELL AND WING OVERHEAT WARNING LIGHT ON

STEADY LIGHT (indicates brake fi re, wheelwell or air conditioning duct overheat) 

*1. BLEED AIR SWITCH (affected side) .............................................................................. OFF 

 2. LANDING GEAR ........................................................................................................... DOWN

 Leave gear extended at least three (3) minutes to allow cooling of overheated brakes in 

order to preclude a brake/tire fi re and tire explosion.

3. GENERATOR SWITCH (affected side) ........................................................................... OFF

NOTE

If the warning light extinguishes, retract the landing gear after 

three (3) minutes cooling and continue fl ight with the bleed air 

OFF; the generator may be RESET/ON. If the light reilluminates 

STEADY, extend the gear. Expect performance degradation due 

to the drag of the gear. A diversion and precautionary landing 

may be necessary. If the light changes to a FLASHING mode complete the wheelwell wing overheat fl ashing items.

CAUTION

IF THE WARNING LIGHT DOES NOT EXTINGUISH WITHIN 

THREE MINUTES, THE AFFECTED ENGINE SHOULD BE 

SHUT DOWN. THE LANDING GEAR MAY HAVE TO BE RETRACTED TO SUSTAIN FLIGHT UNTIL ARRIVING AT A SUITABLE 

LANDING FIELD. 

FLASHING LIGHT (indicates a wing leading edge bleed air line failure or an overheated generator 

wire) 

*1. BLEED AIR SWITCH (affected side) .............................................................................. OFF

2. GENERATOR SWITCH (affected side) ........................................................................... OFF

CAUTION

IF THE WARNING LIGHT DOES NOT EXTINGUISH WITHIN 

THREE MINUTES, THE AFFECTED ENGINE SHOULD BE 

SHUT DOWN. 

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–12 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

HYDRAULIC SYSTEM FAILURE

An emergency hand pump and a cable operated manual release system are provided to extend the 

landing gear in the event of a hydraulic system failure. A stand pipe system in the hydraulic reservoir 

provides a supply of fl uid for hand pump operation. The manual release system also permits free fall 

extension in the event that all hydraulic fl uid is lost.

There are no emergency provisions to extend or retract the fl aps. Landing approach should be 

made at 1.3 VS for the existing airplane confi guration. (For fl aps up confi guration, use 119 KIAS 

at 11,500 pounds gross weight and 5 KIAS less airspeed for each 1,000 pounds less gross weight).

Aircraft equipped with hydraulic nose wheel steering.

WARNING

IN THE EVENT OF A HYDRAULIC SYSTEM MALFUNCTION, 

THE STEERING SYSTEM MUST NOT BE ARMED. STEER 

WITH BRAKES, POWER, AND RUDDER.

LANDING GEAR EMERGENCY EXTENSION

 1. Airspeed ...................................................................................................176 KIAS MAXIMUM 

 2. Landing Gear Handle ..................................................................................................... DOWN 

 3. Emergency Release Lever ..................................................................................ROTATE AFT 

 4. Hand Pump Valve Handle ........................................ PULL PIP PIN/ROTATE VALVE HANDLE 

90 DEGREES FORWARD 

 5. Emergency Hand Pump .........................................................................PUMP AS REQUIRED 

 a. Gear Indicator ...........................................................................ALL DOWN AND LOCKED 

 b. Hydraulic Pressure Gauge .................................................................. 500 PSI TO 800 PSI

NOTE

• If manual extension is used because of a failure in the landing gear 

electrical control system, the hydraulic pressure gauge will continue 

to indicate approximately 2,000 psi system pressure. In this case, 

the pressure to the gear down actuators can be detected only by 

the effort required to move the emergency hand pump.

• If a failure at the bottom of the hydraulic pack allows depletion of all hydraulic fl uid, the emergency hand pump will not 

provide pressure. Nevertheless, Step 3 above will allow the 

landing gear to free fall to a safe, down and locked position.

• Pressure to the hydraulic nose wheel steering system will 

not be available following landing gear emergency extension 

required by either hydraulic failures or gear position selector 

valve electrical failures. Do not arm nose wheel steering.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–13

SWEARINGEN MERLIN 226-T

ELECTRICAL SYSTEM FAILURES (continued)

EXCESSIVE AMMETER INDICATION (continued)

If Step 1 did not correct the excessive ammeter indication:

 2. Nonessential Bus Tie Switch ............................................................................................. OFF

 a. If overload condition still exists, turn nonessential bus tie switch ON and continue to 

Step 3.

 b. If overload condition ceases to exist, pull all circuit breakers on the nonessential bus and 

turn the bus tie switch ON. Reset circuit breakers until the malfunctioning circuit is identifi ed. Pull circuit breaker for malfunctioning circuit and do not reset.

If Step 2 did not correct the excessive ammeter indication:

 3. Left and Right Essential Bus Tie Switches ...........REPEAT THE SAME PROCEDURE FOR 

EACH ESSENTIAL BUS UNTIL SOURCE 

OF THE PROBLEM IS FOUND AND MALFUNCTIONING CIRCUIT IS ISOLATED

BATTERY FAULT LIGHT ON

The battery fault light illuminates when the battery fault detector has actuated:

 1. On Airplanes Equipped with a Single Battery Switch:

 a. Battery switch ...........................................................................................OFF/RESET/ON

If the fault still exists, the light will come back on. In this case:

 b. Battery switch .............................................................................................................. OFF

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–14 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

FAA Approved: June 28, 1976

Revised: November 14, 2014

ELECTRICAL SYSTEM FAILURES (continued)

BATTERY FAULT LIGHT ON (continued)

 2. On Airplanes Equipped with Individual Battery Switches:

NOTE

On aircraft equipped with individual battery switches, a fault 

in either battery feeder circuit will cause both battery bus relays 

to disconnect automatically from the airplane electrical system. 

Both battery bus relays will remain open until either battery 

switch is moved to RESET, then ON.

 a. Both battery switches ................................................................................................... OFF

 b. Left battery switch ............................................................................................. RESET/ON

 If no fault exists in the left feeder circuit, the battery fault light will remain off. In this 

case, leave the left battery switch ON and proceed to Step c.

 If a fault exists in the left circuit, the battery will automatically disconnect and the light 

will come back on. In this case, move the left battery switch to RESET (to reset the 

detector circuit), then OFF and proceed to Step c.

 c. Right battery switch ....................................................................................................... ON

 If no fault exists in the right feeder circuit, the battery fault light will remain off. In this 

case, leave the right battery switch ON.

 If a fault exists in the right circuit, both batteries will automatically disconnect and the 

light will come back on. In this case, move the right battery switch to RESET (to reset 

the detector circuit), then OFF and turn the left battery back on.

NOTE

• Either generator switch, when positioned to RESET, then ON, 

also will reset the battery fault detection circuit.

• All electrically operated components can be operated normally 

on power from the generators when the battery switches are 

OFF.
III–15

SWEARINGEN MERLIN 226-T

ELECTRICAL SYSTEM FAILURES (continued)

BATTERY OVERHEAT WARNING LIGHT ON DURING FLIGHT

1. BATTERY SWITCH (affected side) .................................................................................. OFF

2. Battery Disconnect ......................... NOTE DISCONNECT INDICATION FOR AFFECTED 

BATTERY AND LAND AS SOON AS PRACTICAL

WARNING

• IF POSITIVE DISCONNECT IS NOT VERIFIED, LAND AS 

SOON AS POSSIBLE.

• TAKEOFF AFTER A BATTERY TEMPERATURE WARNING 

LIGHT ILLUMINATES IS PROHIBITED UNTIL THE CAUSE 

OF THE OVERHEAT WARNING IS CORRECTED.

NOTE

A battery temperature red warning light caused by a thermal 

runaway may sometimes be verifi ed by observing sustained 

and excessively high generator loads when the affected battery 

switch is on.

GENERATOR INOPERATIVE – AMMETER INDICATING ZERO

 1. Generator Switch ............................................................................................OFF/RESET/ON

If the generator will not reset:

 2. Generator Switch ............................................................................................................... OFF

CAUTION

DO NOT EXCEED 200 AMPS LOAD ON OPERATING GENERATOR.

CIRCUIT BREAKER TRIPPED

 Circuit Breaker ..............................................................................................PUSH TO RESET

CAUTION

IF CIRCUIT BREAKER TRIPS AGAIN, DO NOT RESET.

INVERTER INOPERATIVE

 • Leave speed levers at high RPM after landing, in order to use alternators. 

 (S/N T–201 through T–248 equipped with alternators and generators)

 • Select other inverter. 

 (S/N T–249 and subsequent equipped with generators – no alternators)

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–16 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

ELECTRICAL SYSTEM FAILURES (continued)

ELECTRICAL BUS FAILURE (indicated by loss of systems on the particular bus)

 1. Left Essential Bus Failure

 a. Left essential bus tie switch ......................................................................................... OFF

 b. Bus transfer switches .......................................................................................RIGHT BUS

 2. Right Essential Bus Failure

 a. Right essential bus tie switch ....................................................................................... OFF

 b. Bus transfer switches ......................................................................................... LEFT BUS

 3. Nonessential Bus Failure

 • Nonessential bus tie switch ......................................................................................... OFF

ELECTRICAL SMOKE OR FIRE

 1. Smoke or Fire from an Essential Bus:

 a. Bus tie switch ............................................................................................................... OFF

 b. Appropriate generator switch ....................................................................................... OFF

If smoke subsides:

 c. All circuit breakers on affected side ............................................................................PULL

 d. Generator switch ............................................................................................... RESET/ON

If smoke does not return:

 e. Bus transfer switches ............................................ SELECT OPPOSITE ESSENTIAL BUS

 2. Smoke or Fire from Nonessential Bus

 • Nonessential bus tie switch ......................................................................................... OFF

TOTAL ELECTRICAL FAILURE

1. ENTRANCE LIGHT SWITCH .........................................................................AS REQUIRED

NOTE

The pilot's overhead and entrance door fl ood lights are battery powered when the entrance light switch is in its ON position.

 2. Both Battery and Both Generator Switches ..................................................................... OFF

 3. Battery Switches (Individually) .............................................................................. RESET/ON

 4. Generator Switches (Individually) ......................................................................... RESET/ON

If total electrical failure occurred as a result of lightning strike or static discharge, the aircraft should 

be thoroughly inspected for evidence of lightning damage. See the SA226 Maintenance Manual, 

Chapter 05 and the TPE 331 Maintenance Manual, Chapter 72.

FAA Approved: October 25, 1977

Revised: November 14, 2014
III–17

SWEARINGEN MERLIN 226-T

NOSE WHEEL STEERING MALFUNCTION

SIDE CONTROL WHEEL SYSTEM (when installed)

If a malfunction (runaway) in the nose wheel steering mechanism occurs that cannot be controlled 

by the normal steering system, release the steering control wheel. Adequate steering then can be 

maintained by use of rudder, brakes, and/or differential power.

NOTE

Normal pilot reaction to a runaway steering system is to oppose the 

malfunction with opposite steering. While this action will stop the 

runaway, it is more effective to release the steering control wheel 

and to maintain directional control with rudder, differential braking, 

and/or differential power.

 1. DIRECTIONAL CONTROL ...........MAINTAIN WITH RUDDER, BRAKES, AND/OR POWER

 2. NOSE GEAR STEERING CONTROL WHEEL ........................................................RELEASE

 3. Nose Wheel Steering Circuit Breaker ...............................................................................PULL

VARIABLE AUTHORITY NOSE WHEEL STEERING SYSTEM (when installed in accordance with 

SB 226 32-032)

Fault protection is provided by circuitry which automatically deactivates the nose wheel steering system if an electrical malfunction occurs. The nose gear then is free to caster and rudder, 

differential braking, and/or differential power can be used for steering.

If the system fails to test correctly, the arm switch should be placed in the OFF position and 

steering accomplished with rudder, differential braking, and/or differential power.

Flashing NOSE STEERING Light

1. DIRECTIONAL CONTROL ...........MAINTAIN WITH RUDDER, BRAKES, AND/OR POWER

2. NWS POWER LEVER BUTTON ..............................................................................RELEASE

 3. NOSE WHEEL STEERING ARM SWITCH ....................................................................... OFF

 4. Nose Wheel Steering Circuit Breaker ...............................................................................PULL

Unwanted Steering Defl ection

 1. DIRECTIONAL CONTROL ...........MAINTAIN WITH RUDDER, BRAKES, AND/OR POWER

2. NWS POWER LEVER BUTTON ..............................................................................RELEASE

 3. NOSE WHEEL STEERING ARM SWITCH ....................................................................... OFF

 4. Nose Wheel Steering Circuit Breaker ...............................................................................PULL

Park Light Illuminated When Park Button Is Not Depressed

 1. DIRECTIONAL CONTROL ...........MAINTAIN WITH RUDDER, BRAKES, AND/OR POWER

2. NWS POWER LEVER BUTTON ..............................................................................RELEASE

 3. NOSE WHEEL STEERING ARM SWITCH ....................................................................... OFF

 4. Nose Wheel Steering Circuit Breaker ...............................................................................PULL

NOTE

It is normal for the park light to remain illuminated, but vary in intensity, 

during the transition from park mode to normal mode.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–18 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

STABILIZER TRIM MALFUNCTIONS

PILOT'S TRIM SYSTEM INOPERATIVE

 1. Trim Selector .............................................................................................................COPILOT

 2. Pilot's Auxiliary Trim Switch, or Copilot's Trim Switches ......................... TRIM AS REQUIRED

COPILOT'S TRIM SYSTEM INOPERATIVE

 1. Trim Selector .................................................................................................................. PILOT

 2. Pilot's Trim Switches ............................................................................... TRIM AS REQUIRED

BOTH PILOT'S AND COPILOT'S TRIM SYSTEMS INOPERATIVE

 1. Trim Selector .............................................................................................. OFF (CENTERED)

 2. Airspeed ....................................... AS REQUIRED TO MAINTAIN LOW ELEVATOR FORCES

 3. SAS Clutch Switch ............................................................................................................. OFF

NOTE

• Turning the SAS clutch switch OFF will reduce required pull 

forces by approximately 20 pounds at approach speeds.

• If the trim system fails in an extreme nose down trim position, 

do not extend fl aps unless required for landing because of the 

subsequent high pull force required to maintain level fl ight.

• If the trim system fails in an extreme nose up trim position, 

fl ap extension (below VFE) will reduce the push force required 

to maintain level fl ight.

On Landing Approach:

 4. Flaps .................................................................................................................AS REQUIRED

NOTE

Flap extension decreases push force requirements.

 5. Landing Gear .................................................................................... DOWN WHEN DESIRED

NOTE

Gear extension increases push force requirements slightly.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–19

SWEARINGEN MERLIN 226-T

STABILIZER TRIM MALFUNCTIONS (continued)

GO-AROUND WITH STABILIZER TRIM INOPERATIVE

WARNING

VERY HIGH PUSH FORCES WILL BE REQUIRED IF THE 

FLAPS ARE RETRACTED WITH THE STABILIZER TRIM IN 

THE EXTREME NOSE UP POSITION. IF A GO-AROUND OR 

BALKED LANDING IS REQUIRED WHEN THE STABILIZER 

TRIM IS STUCK IN AN EXTREME NOSE UP POSITION, DO 

NOT RETRACT THE FLAPS IMMEDIATELY.

 1. Power ................................................................................................................AS REQUIRED

NOTE

Application of power increases push force requirements.

 2. Flaps ........................................................................................... RETRACT IN INCREMENTS

NOTE

Flap retraction increases push force requirements.

 3. Airspeed ............................................... AS REQUIRED TO MAINTAIN LOW STICK FORCES

 4. Landing Gear ............................................................................. RETRACT WHEN FEASIBLE

STABILIZER TRIM SYSTEM RUNAWAY

The application of electrical power to the stabilizer trim actuators is indicated by an aural signal. If 

the signal occurs in fl ight when the trim system is not being operated, the following procedures should 

be initiated immediately:

1. ELEVATOR CONTROL .......................OVERPOWER TO MAINTAIN AIRPLANE CONTROL

 2. TRIM SELECTOR .........................................................................OFF (CENTER POSITION)

 3. Trim Selector ...............................................................OPPOSITE POSITI0N FROM WHERE

MALFUNCTION OCCURRED

 4. Retrim as required

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–20 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

STABILITY AUGMENTATION AND STALL AVOIDANCE

SYSTEM (SAS2) MALFUNCTIONS

SAS FAULT LIGHT ON (STEADY OR FLASHING)

 SAS Clutch Switch ............................................................................................................. OFF

CAUTION

WITH THE SAS DISENGAGED (OR INOPERATIVE) THE AIRPLANE 

WILL HAVE UNDESIRABLE STALL CHARACTERISTICS AT AFT 

CENTER OF GRAVITY LOADINGS. ADEQUATE MARGINS ABOVE 

THE STALL SPEED SHOULD BE MAINTAINED IN ALL OPERATIONS. ENSURE THAT TOUCHDOWN SPEED IS EQUAL TO OR 

GREATER THAN 1.1 VS.

NOTE

• With SAS clutch switch OFF there will be no augmented stick 

forces. Very light elevator forces will be required to maneuver the airplane at airspeeds below approximately 135 KIAS, 

particularly when operating at aft c.g. loadings. Airspeed 

should be monitored closely.

• Fault light on fl ashing indicates a stopped servo or servo 

clutch disengagement.

• Fault light on steady indicates computer power failure, or 

computer power failure with simultaneous servo or clutch failure.

• With the fault light on, angle of attack and stall warning indications 

may be unreliable.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–21

SWEARINGEN MERLIN 226-T

STABILITY AUGMENTATION AND STALL AVOIDANCE

SYSTEM (SAS2) MALFUNCTIONS (continued)

SAS MALFUNCTION – NOSE DOWN

In the event of a nose down malfunction (and no aural tone is noted) the following procedure 

shouldd be initiated:

1. ELEVATOR CONTROL .......................OVERPOWER TO MAINTAIN AIRPLANE CONTROL

 2. SAS CLUTCH SWITCH .................................................................................................... OFF

 3. SAS Circuit Breakers ........................................................................................................PULL

CAUTION

WITH THE SAS DISENGAGED THE AIRPLANE WILL HAVE 

UNDESIRABLE STALL CHARACTERISTICS AT AFT CENTER OF GRAVITY LOADINGS. ADEQUATE MARGINS ABOVE 

THE STALL SPEED SHOULD BE MAINTAINED IN ALL 

OPERATIONS. ENSURE THAT TOUCHDOWN SPEED IS 

EQUAL TO OR GREATER THAN 1.1 VS.

NOTE

With the SAS2 inoperative, there will be no augmented stick forces. 

Very light elevator forces will be required to maneuver the airplane 

at airspeeds below approximately 135 KIAS, particularly when operating at aft c.g. loadings. Airspeed should be monitored closely.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–22 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

STABILITY AUGMENTATION AND STALL AVOIDANCE

SYSTEM (SAS2) MALFUNCTIONS (continued)

AURAL STALL WARNING AT SPEEDS WELL IN EXCESS OF NORMAL STALL WARNING SPEEDS

When an aural stall warning occurs in unaccelerated fl ight at speeds well in excess of the normal 

stall warning speed, possible damage to the angle of attack vane is indicated and an inadvertent 

nose down push may occur.

 1. SAS CLUTCH SWITCH .................................................................................................... OFF

To silence the stall warning horn:

 2. Stall Warning Circuit Breaker ............................................................................................PULL

CAUTION

WITH THE SAS DISENGAGED THE AIRPLANE WILL HAVE 

UNDESIRABLE STALL CHARACTERISTICS AT AFT CENTER OF 

GRAVITY LOADINGS. ADEQUATE MARGINS ABOVE THE STALL 

SPEED SHOULD BE MAINTAINED IN ALL OPERATIONS. ENSURE 

THAT TOUCHDOWN SPEED IS EQUAL TO OR GREATER THAN 

1.1 VS.

NOTE

With the SAS2 inoperative, there will be no augmented stick forces. 

Very light elevator forces will be required to maneuver the airplane 

at airspeeds below approximately 135 KIAS, particularly when operating at aft c.g. loadings. Airspeed should be monitored closely.

YAW DAMPER MALFUNCTIONS

POWER FAILURE

The yaw damper warning light, located on the annunciator panel, illuminates when a power failure 

occurs. If such a failure occurs the yaw damper switch should be turned OFF and care should be 

taken to avoid extreme skidding or slipping turns.

NOTE

Maximum allowable 90 degree crosswind component for landing 

with yaw damper inoperative is 10 knots.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–23

SWEARINGEN MERLIN 226-T

YAW DAMPER MALFUNCTIONS (continued)

ELECTRICAL SERVO RUNAWAY

A runaway can occur when an erroneous electrical signal is transmitted to the yaw damper 

servo primary electrical clutch. The system, is provided with a secondary mechanical clutch that 

prevents excessive rudder forces being generated. Approximately 65 pounds of rudder force is 

required to overcome maximum servo output. If a runaway occurs: 

 1. Rudder Pedals ................................................ AS REQUIRED FOR COORDINATED FLIGHT

 2. Yaw Damper Switch ........................................................................................................... OFF

 3. Avoid extreme skidding or slipping turns.

NOTE

Maximum allowable 90 degree crosswind component for landing 

with yaw damper inoperative is 10 knots.

INSTRUMENT STATIC PRESSURE MALFUNCTION

If the pilot's pressure instruments malfunction, select ALTERNATE position on the static source 

selector valve. The pilot's instruments will be vented to the forward baggage area. See Section 

IV of this manual for corrected airspeed and altimeter readings when operating on the alternate 

source.

NOTE

• The copilot's static pressure instruments are not connected to 

the alternate static pressure source.

• Do not dump pressurization when using the alternate static 

pressure source.

• The altitude and airspeed corrections shown in Section IV of 

this manual are not valid if the dump valve is open.

EMERGENCY EXIT

There is one emergency exit on the right side of the center cabin. The hatch is of the plug type and 

opens into the cabin. To open the emergency exit:

 1. Cabin .............................................................................................................DEPRESSURIZE

 2. Hatch Release Handle ......................................................PULL TOGETHER, THEN INWARD

NOTE

Pull hatch inward, rotate, extend through opening, and discard 

outside the airplane. Ensure that the hatch is clear of the exit 

route from the airplane.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–24 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

WEATHER CONDITIONS CONDUCIVE TO SEVERE IN-FLIGHT ICING:

• Visible rain at temperatures below 0 degrees Celsius ambient air temperature.

• Droplets that splash or splatter on impact at temperatures below 0 degrees Celsius ambient air 

temperature.

PROCEDURES FOR EXITING THE SEVERE ICING ENVIRONMENT:

Monitor the ambient air temperature. While severe icing may form at temperatures as cold as –18 

degrees Celsius, increased vigilance is warranted at temperatures around freezing with visible moisture present. If the visual cues for identifying severe icing conditions are observed, accomplish the 

following:

• Immediately request priority handling from Air Traffi c Control to facilitate a route or an altitude 

change to exit the severe icing conditions. Avoid extended exposure to icing conditions more 

severe than those for which the airplane has been certifi ed.

• Avoid abrupt and excessive maneuvering that may exacerbate control diffi culties.

• Do not engage the autopilot.

• If the autopilot is engaged, hold the control wheel fi rmly and disengage the autopilot.

• If an unusual roll response or uncommanded roll control movement is observed, reduce the 

angle-of-attack.

• Do not extend fl aps during extended operation in icing conditions. Operation with fl aps extended 

can result in a reduced wing angle-of-attack, with the possibility of ice forming on the upper 

surfaces further aft on the wing than normal, possibly aft of the protected area.

• If the fl aps are extended, do not retract them until the airframe is clear of ice.

• Report these weather conditions to Air Traffi c Control.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–25

SWEARINGEN MERLIN 226-T

INADVERTENT ICING ENCOUNTER

If icing is encountered with the ice protection systems OFF, the following procedure should be 

followed.

 1. Ignition Mode Switches ................................................................................................... OVRD

 2. Ignition Light ...........................................................................................................CHECK ON

 3. Engine and Propeller Anti-ice Switch (left engine) ............................................................... ON

NOTE

• Determine that the fi rst engine operates satisfactorily before 

selecting engine and prop anti-ice for the second engine.

• ITT will increase and torque will decrease slightly when 

engine and propeller anti-ice is selected. Power lever 

adjustment may be required.

 4. Pitot Heat/SAS Heat ............................................................................................................ ON

 5. Windshield Heat Switch ....................................................................................................HIGH

 6. Deice Boots Switch ........................ AUTO (AT THE FIRST SIGN OF ICE FORMATION 

ANYWHERE ON THE AIRCRAFT) 

 7. Engine and Propeller Anti-ice Switch (right engine)............................................................. ON

NOTE

• Observe ignition duty cycles.

• Excessive use of override mode will reduce igniter plug life.

WARNING

ENGINE HEAT AND CONTINUOUS IGNITION, IN THE OVERRIDE 

MODE, MUST BE USED AFTER LEAVING ICING CONDITIONS 

UNTIL THE PILOT IS CONFIDENT THAT ANY SIGNIFICANT 

RESIDUAL ICE ON PROPELLERS, SPINNERS, OR INLET LIPS 

WILL NOT BE SHED INTO THE ENGINE INTAKES.

FAA Approved: June 28, 1976

Revised: November 14, 2014
III–26 FAA Approved: November 14, 2014

SWEARINGEN MERLIN 226-T

INTENTIONALLY LEFT BLANK