🛫 Prop Pitch-Lock & Prop Feather — AFM Normal Procedures

Source: AFM Section 4 — Normal Procedures

Aircraft: L-410NG (EASA Approved)

Pages: 4-19 to 4-22

Date: 24 May 2026

✅ Test 42: LH (RH) Pitch-Lock — AFM Section 4-19

    วัตถุประสงค์: ทดสอบระบบ Pitch-Lock ของใบพัดเครื่องซ้าย/ขวา
  

(38) ON THE TOUCH SCREEN CONTROLLER:
Home → Aircraft systems → System Selection → System Tests section

(39) LH (RH) Pitch-Lock key ........................................ press at propeller speed about 400 RPM

📋 ผลที่คาดหวัง (Expected Results)

1. Propeller speed stops rising for 4 sec. at about 700 RPM

2. Yellow LH (RH) PROP PITCH-LOCK message displays on PFDs

3. Yellow MASTER CAUTION displays

4. One chime is heard

5. White LH (RH) BETA RANGE message also displays

6. White LH (RH) LIMITER ACTIVE message also displays

7. After 4 sec. → propeller speed rises up to idle speed

8. All annunciations disappear

9. Blue Done is displayed on LH (RH) Pitch-Lock key after test finishing

✅ Test 42: LH (RH) PROP FEATHER — AFM Section 4-19 to 4-20

    หมายเหตุ: ทดสอบก่อนเที่ยวบินแรกของวัน (Before first flight of the day)
  

a) LH and RH PCL .................................................................................... FINE PITCH

b) LH and RH TCL .................................................................................... to over 35% torque position

c) ON CENTRAL CONTROL PANEL:
GROUND SPOILERS/AUTO BANK/AUTO FEATHERING switch .................... check ON

→ Blue SPOILERS ARMED and AUTO-BANK ARMED messages display on both PFDs

d) ON TOUCH SCREEN CONTROLLER:
Home → Aircraft systems → System Selection → System Tests section

e) LH (RH) Prop FTHR key .......................................................................... press

→ Cyan AUTO-FEATHER ARMED messages must display on PFDs within 8 seconds

f) TCL of LH (RH) engine .......................................................................... IDLE

→ Blue AUTO-FEATHER ARMED and AUTO-BANK ARMED messages disappear from PFDs

→ Blue LH (RH) PROP FEATHERING message displays on PFDs

→ White RH (LH) AUTO-BANK ACTIVE message displayed for 6 sec. (ABC tab extended)

→ White LH (RH) ISOLATION VALVE OPEN message remains displayed up to auto feathering system reset

→ Blue Done displays on LH (RH) Prop FTHR key after test finishing

⚠️ CAUTION: AT LOW AMBIENT TEMPERATURES KEEP CHECK ON THE GAS GENERATOR SPEED, WHICH MUST BE AT LEAST 60%. IF NECESSARY INCREASE IMMEDIATELY THIS SPEED BY MEANS OF THE FUEL STOP COCK / EMERG THROTTLE LEVER.

g) TCL of the opposite engine ................................................................... back to IDLE

h) FUEL STOP COCK / EMERG THROTTLE lever .................................. back to OPEN
(if this lever has been used in the procedure)

i) GROUND SPOILERS/AUTO BANK/AUTO FEATHERING switch ........... switch OFF and back ON

→ Propeller will be unfeathered

    ทำซ้ำสำหรับเครื่อง引擎อีกข้าง: ใช้ same procedure เพื่อ check automatic feathering system ของเครื่องอื่น
  

✅ BETA RANGE Check — AFM Section 4-22 (Taxiing)

(6) LH/RH BETA RANGE CAS MESSAGE .............................................. CHECK
เมื่อ TCL is moved from IDLE to REVERSE position

⚠️ CAUTION 1: AVOID REVERSING AND FEATHERING AT ZERO SPEED, USE PROPELLER FINE PITCH AND IDLE POWER SETTINGS INSTEAD.

⚠️ CAUTION 2: IF THE "LEFT/RIGHT HYDRAULIC OVER TEMP" MESSAGE APPEARS ON THE PFD, THE TAKE-OFF IS PROHIBITED. INFORM GROUND STAFF ABOUT THE FAILURE.

🛫 Taxiing — Propeller Procedures ที่เกี่ยวข้อง (AFM Section 4-21)

(2) FINE PITCH PROPELLER SETTING ................................................. USE FOR REDUCING TAXI SPEED

(3) PROPELLER HYDRAULIC SYSTEM ................................................. VENT BY FEATHERING THE LH AND RH PROPELLER USING PCL. RETURN THE PCL WHEN THE RPM DROPS FROM 350 TO 400 RPM

⚠️ CAUTION: USE FEATHER POSITION SETTING FOR SHORT TIME (MAX 30 SEC., DUE TO POSSIBILITY LEADING EDGE SURFACE OVERHEATING)

(4) REVERSE POWER SETTING ............................................................ CHECK

(5) PCL ...................................................................................................... FINE PITCH

📊 CAS Messages ที่เกี่ยวข้อง

CAS Message	สี	ความหมาย	สถานะ
LH (RH) PROP PITCH-LOCK	Yellow	Pitch-lock test active	4 sec.
LH (RH) BETA RANGE	White	Beta range signaling	During test
LH (RH) LIMITER ACTIVE	White	Limiter system active	During test
LH (RH) PROP FEATHERING	Blue	Feathering in progress	12-15 sec.
AUTO-FEATHER ARMED	Cyan	Auto-feather system ready	Check
AUTO-BANK ARMED	Blue	ABC tabs system ready	Check
SPOILERS ARMED	Blue	Spoilers system ready	Check
LH (RH) AUTO-BANK ACTIVE	White	ABC tab extended	6 sec.
LH (RH) ISOL VALVE OPEN	White	Emergency circuit active	Post-feather
MASTER CAUTION	Yellow	Alert active	During pitch-lock test

🎯 Quick Reference

Pitch-Lock Test: Press key at ~400 RPM → wait 4 sec. → check yellow message

Prop Feather Test: PCL = FINE, TCL > 35%, Auto-feather ON → press key → TCL IDLE

Unfeather: Auto-feather OFF then ON → propeller unfeathers

Beta Range Check: Move TCL from IDLE to REVERSE → check CAS

🚨 BETA RANGE & PROP PITCH-LOCK — Abnormal Procedures (AFM Section 3A-10 to 3A-11)

a) On Final Approach:

TCL → IDLE
MANUAL FEATHER push-button (under cover) → PUSH
PCL → FEATHER

b) During Take-off:

Below V1 → Abort take-off
Above V1 → ELU LH, RH → switch off → complete take-off
หลัง take-off → ทำตาม procedure c)

c) During Other Phases:

BETA RANGE แสดง + PROP PITCH-LOCK ไม่แสดง → False signaling
ELU LH, RH → switch off → No further action required

BETA RANGE + PROP PITCH-LOCK แสดงทั้งสอง:
ELU LH, RH → switch off
Continue flight
Before descent: TCL → IDLE, MANUAL FEATHER → PUSH, PCL → FEATHER
Engine → SHUT DOWN
Complete flight with one engine inoperative

⚠️ CAUTION: ANY POWER REDUCTION UNDER 80% NG CAN CAUSE A DIFFERENCE IN PROPELLERS SPEEDS, I.E. A THRUST ASYMMETRY.

📖 AFM References

หัวข้อ	Section	Page
Pitch-Lock Test	4 - Normal Procedures	4-19
Prop Feather Test	4 - Normal Procedures	4-19 to 4-20
Beta Range Check	4 - Normal Procedures	4-22
Taxiing Procedures	4 - Normal Procedures	4-21
BETA/PITCH-LOCK Abnormal	3A - Abnormal Procedures	3A-10 to 3A-11
Unfeathering	3A - Abnormal Procedures	3A-10