Octane ratings are posted on fuel dispensers. CAUTION: Follow the fuel recommendations in your vehicle owner's manual. If your vehicle requires premium 91 or higher octane fuel, use a premium grade of gasoline. The least amount that's necessary to prevent detonation (spark knock). On most vehicles, that would be regular unleaded 87 octane gasoline.
The basic pay for any member of the U.S. military is based on two factors, rank and time of service. For an Air Force E-4, pay begins at $1,947 a month, or $23,364 a year, for those with less than two years of service.
All government workers, including aerospace engineers for the Air Force, use the same General Schedule pay tables. This divides salaries into grades, based on education, experience and position. It further subdivides grades into steps, which are intermediate earnings between grades. Aerospace engineers start at GS-7. According to the Office of Personnel Management, the base salary for that grade begins at $33,979 per year for step 1 but can increase to a maximum of $44,176 at step 10. At GS-10, step 1, salaries start at $45,771, and at GS-15, the highest grade, they start at $99,628. The maximum step 10 salary for this grade is $129,517 per year. Recognizing that costs of living vary by area, the government also uses locality tables to vary the salary of aerospace engineers in the Air Force.