In June of 2006, the AFA Air Safety, Health and Security Committee responded to numerous complaints by flight attendants at Executive Airlines concerning excessive heat and fatigue experienced in ATR-72 cabins on a daily basis. 

With the support of AFA International., a temperature sampling program was created in order to capture accurate data across the Executive Airlines fleet. 20 volunteer flight attendants were recruited and trained by AFA in the use of specialized equipment and record keeping, and the samples which were collected not only supported claims of unsafe working conditions, in some cases, the data indicated dangerous levels of heat exposure. 

August 2006 was the month chosen for the study, which we felt would give a broad range of operating environments. August is not the hottest month of the year in the Caribbean, due to hurricane season, and there were several tropical storms which impacted Executive Airline’s operations during the month.

The instruments used for data collection were calibrated digital thermo-hygrometers built by Extech, a reputable manufacturer of laboratory and field test equipment. The tolerances for these instruments provided very accurate measurements for our study, as noted by the instrument tolerances, which allowed us to calculate the heat index for each sample taken. The instruments simultaneously capture temperature and relative humidity information.

AFA collected just under 650 temperature samples in total, of which 585 were useable. Samples which were not included in the study were incomplete or, in some cases, illegible. This is a copy of our data sheet, which every volunteer used to capture data during every flight that they operated during the month of August. Our volunteers included line holders, reserves, senior, and junior flight attendants. We are quite confident that we captured a broad range of flying at Executive Airlines. 

On every flight, temperatures were recorded at the exact same location for consistency: the number 2 flight attendant jumpseat, which is located in the front of the cabin. Each flight included two samples at this location: the first sample was taken just after passenger boarding and prior to closing the main aircraft door for departure, and the second sample was taken in flight at the top of descent. 

The objective of taking these two samples on each flight was to accurately observe the cabin temperature which passengers and crew were exposed to before take-off, and to then accurately observe what the cabin temperature was at the point of maximum cooling in flight, commonly accepted as the top of descent for landing.

Once the temperature data was collected, it was transferred to a database and triple checked for accuracy. Once confident that the data was correct, we calculated the heat index for every sample. This slide details the NOAA formula for calculating the heat index, as established by the US Government.

This table details the US Government’s analysis of potential heat disorders within various heat index ranges. You may want to refer back to this table periodically as you review the data in following slides.

Here is how the various caution and danger levels break out over a graph of the heat index referenced by temperature and relative humidity. None of the samples collected by AFA were in the extreme danger zone.

This is a broad view, in pie chart form, of the pre-departure samples taken on all flights and at all times of the day and night. The chart shows that 80.6% of the flights surveyed operated in the caution to danger areas of the heat index. 24.2% operated in extreme caution and higher, as depicted.

Here we have a broad view of how well the subject aircraft cooled in flight, as measured at the top of descent. Overall, 70.8 % of the aircraft cooled below the warning threshold, with 29.2% still operating above the warning threshold

We decided to view the data by time of day, starting here with the pre-departure samples. For purposes of the study, morning included 6am to 10am local; mid-day: 10 am to 2pm; afternoon: 2 pm to 6pm; evening: 6pm to 10pm; night: 10pm to 6am. 

As expected, the airplanes get quite warm during mid-day to evening, however, we were surprised at how hot the aircraft get in the mornings before 10 am. We feel this may be due to the outside temperature being comfortable while the aircraft, in direct sunlight, begins to absorb a heat load.

Here is a look at how well the aircraft cooled enroute, broken out by time of day. Again, the morning figures are quite a bit higher than we anticipated.

For a better understanding of where these hot temperatures were occurring, we broke out the data by station, including only stations for which we had 10 or more samples. FLL really stands out here, supporting numerous flight attendant complaints. The two hubs, MIA and SJU also stand out, since they are also near the top of the chart for hot boarding temperatures, yet these are the two stations where cooling equipment is most readily available.

This slide depicts boarding data by tail number, to identify which aircraft might have particular problems on the ground. There are several tail numbers which stand out as being problematic.

Here is a view of how the aircraft cooled enroute, by tail number. When you compare this slide to the previous slide, there are a couple of surprises: some of the oldest aircraft, such as N004, cooled very well enroute. Other aircraft, once subjected to a heat, were never able to shed the load enroute, such as N425.

These are a few of the comments supplied by flight attendants during the study, completely at random. These comments were not selected according by any criteria, but rather by randomly picking reports with comments added.

To conclude, AFA feels that this study provides a first ever glimpse at just how significant the heat problem is at Executive Airlines, using calibrated equipment, specialized collection training, and rigorous collection protocols. We have made several recommendations to senior management to address this problem, and we look forward to continuing our work to provide a safe operating environment for our passengers and crew members.