F-22 Plus-Up Environmental Assessment - Joint Base Elmendorf ...

F-22 Plus-Up Environmental Assessment
4.0 Environmental Consequences
potentially have negative consequences for animals living in the Knik Arm. Of particular
concern would be any impacts to the CIBW, which was recently listed as endangered under
Section 7 of the ESA. An in-depth analysis was conducted to assess risk to the CIBW resulting
from additional F-22 flying operations. This analysis is described in Section 3.2, and in greater
detail in Section 4.6, (Biological Resources) and Appendix E, Section 7 (Endangered Species Act)
Compliance Wildlife Analysis for F-22 Plus Up Environmental Assessment. The analysis found that
implementation of the Proposed Action has the potential to increase the number of CIBW
behavioral harassments by approximately 0.04 events annually. As discussed in Section 4.6, the
NMFS has determined this increase may affect but is unlikely to adversely affect the CIBW.
Overall, noise impacts in the base vicinity associated with implementation of the Proposed
Action would not be expected to be perceived as significant.
4.2.2 Training Airspace Environmental Consequences
The program MR_NMAP was used to calculate subsonic L dnmr in the training airspace units
under baseline conditions and the Proposed Action. Under the Proposed Action, F-22 aircraft
would not fly in any airspace units that are not being used by the F-22 currently. Furthermore,
F-22 aircraft would conduct training in the same altitude bands used currently, and sortieoperations
conducted after 10:00 p.m. would continue to be rare. The only change expected to
occur relative to baseline conditions would be an increase in the annual number of F-22 sortie
operations proportionate to the number of plus-up aircraft. Baseline conditions reflect the
relocation of the Kulis ANG to JBER and the recent departure of the 19 FS, which had operated
F-15C aircraft.
The change in L dnmr between baseline conditions and the Proposed Action would be 1 dB or less
(Table 4.2-3). To put this degree of change in perspective, changes in instantaneous noise levels
of less than 3 dB are typically not noticeable in non-laboratory conditions. Under the Proposed
Action, noise levels beneath all training airspace units except Eielson and Viper MOAs would
be below 55 dB L dnmr, the USEPA-identified threshold below which impacts to human health
and welfare are not expected to occur (USEPA 1974). Noise levels beneath Eielson and Viper
MOAs would increase by 1 dB to 59 and 57 dB L dnmr, respectively. This increase would not be
discernible to residents or visitors to the area.
F-22 aircraft training in the MOAs and ATCAAs would fly supersonic at the same altitudes, the
same number of times per sortie, and for the same length of time per sortie as current F-22
sortie-operations in the training airspace. As F-22 operations would increase, the number of F-
22 supersonic events would also increase by approximately the same percentage. Data on the
current and proposed flying operations of the F-22 and other supersonic-capable aircraft using
the training airspace were entered into the program BOOMAP to generate CDNL beneath each
airspace unit. Increases in CDNL would be 1 dB or less and would be 54 dB L dnmr or less (Table
4.2-3).
The enhanced supersonic performance of the F-22, which contributes to its success in combat,
means that F-22 sortie-operations result in more sonic booms on average than sortie-operations
conducted by fourth generation fighter aircraft currently operating in the training airspace (e.g.,
F-16 Aggressor aircraft flying from Eielson AFB). Recordings made during multiple air-to-air
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