Bat Birds Pull to Left

[munirabbasi 13]

Hello World Expertise 

Aircraft pulled to left during fast taxing.Replaced Steering control valve ,Brakes assembles(04). Rudder ragging. and Nose wheels and Nose  mounting toque checked. MLG shock strut servicing and balancing C/Out  and MLG tire pressure checked but defect could not troubleshoot (Repeat)

Munir Abbasi

Home of hercules Pakistan  

[NATOPS1 20]

I see you have already checked your struts, take a look at the wing fuel balance and wind conditions; also the FCF has specific engine settings FF and torque when checking the NWS for satisfactory operation but it is at much reduced speed. At higher speeds there are a number of factors your crew can look for: roll input (check at different flap settings); ask them to note control surface pressure (rudder and yoke, pitch and aileron) (external forces input) Also have the crew check torque settings on the right engines vs left as higher torque will cause track deviation.   

[Moeed hassan 0]

2 hours ago, NATOPS1 said:

I see you have already checked your struts, take a look at the wing fuel balance and wind conditions; also the FCF has specific engine settings FF and torque when checking the NWS for satisfactory operation but it is at much reduced speed. At higher speeds there are a number of factors your crew can look for: roll input (check at different flap settings); ask them to note control surface pressure (rudder and yoke, pitch and aileron) (external forces input) Also have the crew check torque settings on the right engines vs left as higher torque will cause track deviation.   

How about anti-skid system???? 

[NATOPS1 20]

9 minutes ago, Moeed hassan said:

How about anti-skid system???? 

Should not be a factor; you can switch it on (or off) and most likely have the same drift issue as the brakes should be disengaged during the roll.

[munirabbasi 13]

8 hours ago, NATOPS1 said:

I see you have already checked your struts, take a look at the wing fuel balance and wind conditions; also the FCF has specific engine settings FF and torque when checking the NWS for satisfactory operation but it is at much reduced speed. At higher speeds there are a number of factors your crew can look for: roll input (check at different flap settings); ask them to note control surface pressure (rudder and yoke, pitch and aileron) (external forces input) Also have the crew check torque settings on the right engines vs left as higher torque will cause track deviation.   

Thanks

Best regards

Munir Abbasi Home of hercules Pakistan

[hehe 33]

1.  What speed?

2.  Does pilot have to use opposite steering wheel inputs to correct?

3. Has neutral/streamline of rudder control surface, trim tab and boostpack been checked?

4.  Are the nose tires the same tread pattern and height?  if you stick a level across the top of nlg tires, it should be level or match the level of your surface (ground).

5. Has back pressure been checked for brakes?  should be no more than 70 psi in return pressure.  Anything more can create a dragging brake.  Easiest way to find a dragging brake is have crew taxi for about 10 minutes and check temperatures of brakes, they should be similar between left and right side.  Brake bleed kit can check back pressure.

6.  Have you checked rigging of steering cable/chain

7.  Have you checked the NLG scissors and bolts for tightness?  Slop in the scissor linkage can create a very uncontrollable NLG steering

Edited November 28, 2018 by hehe

[munirabbasi 13]

19 minutes ago, hehe said:

1.  What speed?

2.  Does pilot have to use opposite steering wheel inputs to correct?

3. Has neutral/streamline of rudder control surface, trim tab and boostpack been checked?

4.  Are the nose tires the same tread pattern and height?  if you stick a level across the top of nlg tires, it should be level or match the level of your surface (ground).

5. Has back pressure been checked for brakes?  should be no more than 70 psi in return pressure.  Anything more can create a dragging brake.  Easiest way to find a dragging brake is have crew taxi for about 10 minutes and check temperatures of brakes, they should be similar between left and right side.  Brake bleed kit can check back pressure.

6.  Have you checked rigging of steering cable/chain

7.  Have you checked the NLG scissors and bolts for tightness?  Slop in the scissor linkage can create a very uncontrollable NLG steering

Thanks Defect has been rectified

Munir Abbasi 

Home of hercules Pakistan

[hehe 33]

9 minutes ago, munirabbasi said:

Thanks Defect has been rectified

Munir Abbasi 

Home of hercules Pakistan

What was the fix?

[munirabbasi 13]

9 hours ago, hehe said:

What was the fix?

MLG Shock strut balancing problem

Best regard

Munir Abbasi home hercules Pakistan