Maximum Load

.

Ultimate Load =

..

..

Load Factor

So the ultimate loads in each direction are: Ultimate Load FORWARD = FX FORWARD / nFORWARD =1.5 F / nFORWARD Ultimate Load AFT = FX AFT / nAFT = 1.5 F / nAFT Ultimate Load RIGHT = FY RIGHT / nRIGHT = 1.86 F / nRIGHT Ultimate Load LEFT = FY LEFT / nLEFT = 1.86 F / nLEFT Ultimate Load UP = FZ / nUP = 5.44 F / nUP

A. LOADING GENERALITIES

e) Summary
This whole method can be summarized in the following table:
 Angle  Force Breakdown 
Tie down Point Pos. Restraint  α (°)  β (°)  FWD +  AFT - LH +  RH - UP + 
AFTLeft UP  30 60  150 90  75% F  43% F 50% F  50% F 86% F 
136% F 
FORWARD Left UP  30 60  30 90  75% F  43% F 50% F  50% F 86% F 
136% F 
AFTRight UP  30 60  210 90  75% F  43% F 50% F  50% F 86% F 
136% F 
FORWARD Right UP  30 60  330 90  75% F  43% F 50% F  50% F 86% F 
136% F 

Total Maximum Load Allowed  150% F  150% F  186% F  186% F  544% F 
Load Factor  nFWD  nAFT  nLEFT  nRIGHT  nUP 
Ultimate Load  150% F / nFWD  150% F / nAFT  186% F / nLEFT  186% F / nRIGHT  544% F / nUP 
ULTIMATE LOAD  Minimum of the Ultimate loads 

This method can be applied for as many as needed tie down points, adding each time a strap in
the direction which limiting the ULTIMATE LOAD.
Then tables like the following one can be issued and published in the loading manuals of
operators.

Load to be restrained  Number of single stud fittings  Number of straps hooked on 2 single stud fittings 
kg  FWD  AFT  UP 
less than 800  4  1  1  2 
801 to 1420  6  2  1  3 
1421 to 1600  6  2  2  3 
1601 to 2400  8  3  2  4 
2401 to 3200  10  4  3  5 
3201 to 4010  12  5  4  6 
> 4010  14  6  5  7 

LOADING LOADING

A. LOADING GENERALITIES

Note : the recommended 30° between the rope or the strap with the main direction of restraint enables a high restrained force in the needed direction, indeed by increasing this angle, one decreases the weight that can be restrained by the item. Nevertheless some operators might choose even when applying the recommended 30° to perform the computation with an angle of 45° in order to take into account a margin in case one of the ropes in not correctly tied down.
 Angle  Force Breakdown 
　
中國航空網(wǎng) m.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：Getting to Grips with Aircraft Weight and Balance(111)