Part 121 and Part 135 Operations in the USA
Part 121 and Part 135 Operations in the USA
Passenger safety is the main concern of the U.S. aviation industry. As passenger enplanements in the U.S. dramatically increase, more individuals and institutions are becoming more concern on the survivability of each flight.
The purpose of the study was to determine the difference in accidents and incidents between Part 121 and Part 135 Operations in the US. Part 121 covers all air carrier operations like for hire carriers. Part 135 covers all air taxi and commuter program and both include operations that are scheduled and non-scheduled. The data gathered and published by the Federal Aviation Administration (FAA) in the appendix in figure 2 will be used for this study. The observed number of accidents and incidents from 1978 to 2014 will serve as the dependent variable while the group memberships, that is the U.S. operations under Part 121 and Part 135 will be the independent variable.
Aircraft operations have two types – scheduled and nonscheduled operations. Scheduled operations are those flights which were planned and mapped at specific dates and time. Nonscheduled operations on the other hand are those flights that were done when the needs arise. These operations require permit on specified location of travel as it is operates without published schedule.
Incident is defined as the event that occurred associated in the operation of an aircraft apart from accident that may affect the safety of the operations. Accident on the other hand refers to any event that happened between the aircraft within the boarding of a person who has the intention of flying it which may cause injury or death to any person inside it.
The research question of the study was What is the difference in accidents and incidents between Part 121 and Part 135 operations in the U.S? This study will work to disprove the null hypothesis which states that there is a significant difference in the accidents and incidents between Part 121 and Part 135.
The null hypothesis states that there is No significant difference in between part 121 and part 135 accidents and incidents while the alternative hypothesis states that there is a significant difference in between part 121 and part 135 accidents and incidents
The population of the study is all U.S. pilots who operate under Part 121 and Part 135. On the other hand the sample of the study are the accidents and incidents that occurred under Part 121 and Part 135 operations from 1978 to 2014.
Methodology
The research methodology in this study is conducted by an ex post facto research, because I have preexisting groups.
This study will use a total sample of 74 cases that will include all U.S accidents and incidents that occurred under Part 121 and Part 135 operations. The number of accidents and incidents will serve as the dependent variable; while the group membership which is Part 121 and Part 135 will serve as the independent variable. The parameter of the study includes all U.S. accidents and incidents that occurred from 1978 to 2014 under Part 121 and Part 135. The data collection method used was archival data. I did this by searching information from the FAA data base. No human subject issues were involved as the data was convenient and available to the public.
Data Analysis
The distribution the mean of the study is 77, while the median is 63 and the range of the study is 239. The distribution is skewed to the right because the mean is located to the right of the median. This is shown in Figure 6.
An outlier analysis is then done as the data used present real case scenario of accidents and incidents that occurred I chose to conduct my study with outliers present. With this choice the power of my study will also be higher.
When I tested for levene to figure out whether I am going to do a pooled t test or a normal t test, p(levene) was significant because p(levene) = 0.0001 < alpha (α) = 0.05 which is not equal, thus a normal T test was used, figure 5 in the appendix support my answer.
A two tailed test will be conducted to identify the relationship as it is the appropriate test for comparing mean difference between two samples. The sample is from an independent population so the degrees of freedom result is 72. The computation resulted to T-ratio = 3.996. Having ± 1.98 as the critical region, the resulted T-ratio falls in the critical region.
This result concludes that the null hypothesis is rejected since there is a significant difference between Part 121 and Part 135. Part 135 Averaged 38.24 points higher on accidents and incidents than part 121. Therefore parts 135 have higher accident and incident rates than part 121.
The effect size of the data used is computed resulting to 18.2% of the variance of Accidents and Incidents is being explained by part 121 and part 135 operations. With power equals to 0.9763; there is a 97.63% probability of having a true effect; what I found in the sample truly exists in the population. This study has a result of 95% confidence interval. Based on the results, if we were to randomly select 100 samples from the two population each of size samples of size n= 37, then 95 of those samples would have a difference in accident and incidents rates between 18.94 to 57.55. Zero is not a possible value and this confirms to Reject Ho. The accuracy in parameter estimation is moderately accurate as I have a large interval which is a good estimation of population parameter which is significant.
Discussion
Based on the result of this study, it was determined that the rate of difference between the accidents that happened under Part 121 and Part 135 is significant. This is possibly because the requirements for part 121 pilot training are more extensive than Part 135 pilots; because of the extra training 121 pilot’s have lower accidents and incidents rate.
The absence of data earlier than 1978 for both part 121 and part 135 US operations serves as the limitation of this study. The inclusion of the data from the earlier years may not guarantee the yielding of same results.
The study only uses the data under Part 121 and Part 135 of U.S. operations. The U.S. operations have other operations which may provide different results to this study.
The determined results rejected the null hypothesis that there is No significant difference in between part 121 and part 135 accidents and incidents. With the outcome disproving that, I have learned that it is safer to transport through operations under part 121 operations.
Appendix
Figure 1 .. A priori Analysis
Figure 2 .. Data Set
Figure 3 .. Outlier Analysis
Figure 4 ..T-Test Outliers Absent
Figure 5 .. T-Test Outliers present
Figure 6 .. Distribution Analysis
