# Fall Testing of the Personal Airborne Equipment Backpack: Ground and Flight Testing
## 5 Conclusions  
The ground and flight tests of the backpack TL-98 confirmed its functionality and reliability according to the definitions mentioned in Section 2. In terms of safety, the trouble-free backpack fixation on the parachutist's gear during dropping from an aircraft, parachute opening, and parachute flight itself were affirmed. The trouble-free backpack release off of the parachute gear, the stopping of the backpack's free-fall by the rope, and parachute operation with the backpack hung on the rope were also confirmed.  
Figure 12: Comparison of the force impact values during fall tests 1 and 4.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **1 st Maximum Force** & **2 nd Maximum Force** & **3 rd Maximum Force** \\  & **[N]** & **[N]** & **[N]** \\ \hline fall test 1 & 3129 & 1099 & 530 \\ fall test 2 & 3816 & 1452 & 697 \\ fall test 3 & 3826 & 1207 & 687 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison of the three highest maximal force impact values during fall tests.  
For reasons of defining the rope's operational life, one that retards and stops the backpack TL-98's fall, the below mentioned principles were defined:  
* the measured force impact values for the rope must not exceed 50%, even in a single case, of the values of the tensile strength guaranteed by the producer;
* all the fall tests must preserve functionality and reliability (in terms of the definition presented in Section 2);
* in the case when two of the above mentioned conditions have been met, then the rope's lifetime for live parachutist operation can be defined in the form of the maximal number of rope disposals (the maximal number times retarding and stopping TL-98 backpack free-falls) and as follows: the number of flight tests (the test dummy deliveries) without a measurement of the force impact values of a 60 kg backpack (the 50 kg backpack's maximal operational weight multiplied by the safety quotient of 1.2) while preserving functionality and reliability according to the controlled characteristics multiplied by 10.  
Six flight tests were performed in the range of this project and resulted in the conclusion that serviceable use of the rope in live parachute operation can be assigned for up to 60 applications [11].  
The tasks included in [6; 7; 16] became basics for elaborating the procedures to define the retarding and stopping in the TL-98 backpack rope's lifetime. The operational life of a rope is generally considered as an abstract question. It is difficult to define a rope's exact operational life. Ropes with a lifetime of 10 years are also currently available. However, in the case of free-fall capture with a higher value of the fall factor, manufacturers generally do not recommend further use. The value of this fall factor varies from manufacturer to manufacturer and ranges from approximately 0.5 to 1.5. Of course, it is also important whether the rope was stressed over a sharp edge. Rope lifetime can be specified only approximately. It depends on many factors, such as the forms of utilization, rope type, care of the rope, its storage, climate conditions, etc. The number of successful fall retardations and stops, rope use, and age can all degrade a rope's ability to retard and stop a fall [6].