All the aircraft we fly have certain restrictions based to their flying capability. These limitations really must be heeded by the pilot, for immediate and long-term aircraft viability and safety. For example, one limitation might be the maximum airspeed the aircraft can fly.   Unfortunately,  in 2002, a test pilot’s F-15 disintegrated over the Gulf of Mexico doing a high speed test, killing the pilot.   The basis of the investigation reduced the maximum speed of the F-15 to 1.8  . He was pushing Mach 2.0 when the vertical stabilator dismantled.    I feel fortunate that this had not happened to me one time when I pushed the jet to almost Mach 2.0 (the mach meter just couldn’t quite reach the 2.0 limit) in a high altitude dive when our adversaires cancelled our fight.  I tried the same thing once as a young Lieutenant while at Bergstrom flying the F-4.    It was basically suggested by my WSO (to remain nameless) that we should try to get above Mach 2.0; which I enthusiastically and naively embraced.   We put it the jet in a low gravity dive at about 35,000 feet with full afterburner.    The jet started shaking as we (literally) plummeted to the earth.    (All phantom drivers know that the F-4 has the aerodynamic characterics of a flying brick, and that day we just let the brick drop).    For me, the funniest part was that after I selected full afterburner, I kept feeling the throttles bumping forward, knowing the backseater was ensuring we got every ounce of thrust we could out of those J79s.

Another story I outlined earlier happened in regard to material stress at the following link.

So, beyond airspeed, one of the most critical and difficult restrictions to meet was the G-limit on the aircraft. The G-limit is how many times the weight of gravity you could pull (the stick) in a turn before permanently damaging the aircraft. When studying “materials” in college, I remember that there is designated amount of force that can be put on a material that doesn’t cause it to bend or break permanently. Of course,  another limitation is how many times that material can be stressed before it fatigues, weakens, cracks, or other generates another unpredictable issue challenge.

The amount of G-s one could pull is dependent (physics) on the altitude and airspeed of the aircraft. From the equation below, density (related to altitude) and velocity squared (airspeed), effect the amount of Lift (or G-load). I apologize for getting so technical; but I really never get to use any of my Bachelor’s degree information.

The challenges is that whenever dogfighting, the goal is to either “shoot” your opponent, or to not get “shot” by your opponent. An aircraft making a tighter turn (with other geometric advantages) usually has the advantage. Getting the advantage often meant pulling more G’s. Therefore, to win meant to fly the jet to its limit but not over the limit.

Over the limit meant “Over-G”

If you Over-G’d the aircraft, you had to stop the fight, have someone visually check out the aircraft and confirm nothing obviously broken, and then fly home without maneuvering to a straight-in approach. The rest of your angered flight would have to either escort you home or do an alternative mission.

You also created a major burden for maintenance, since (dependent upon the amount of Over-G) they would need to examine panels, test the force bearing structure, look for cracks and damage (using X-ray and dyes), and potentially reducing the flight life of the aircraft.

While flying, the trade-off of avoiding maximum performance was getting shot (and killed in combat) by the adversary.

To know how many G’s you were pulling, you had a G-meter in the aircraft and displayed on the “Head’s Up Display” which is recorded for post-flight viewing and verification. Also, “Bitching Betty” the verbal cue in the aircraft starts beeping when approaching the G-limit and gives a steady beep when at the limit. If you exceed the limit, Betty says “Over-G, Over-G, Over-G” usually followed by a few swear words from the pilot.

In the debrief, if a pilot flew their jet to the steady beep, but did not exceed it, they would be lauded. Some of our most talented (Weapon’s School Graduates or Nuts) would ride that beep steady. I was often too afraid to Over-G to go into the steady beep and hope to hit the beeps.

So you can see the incentive for young pilots is to get to the steady beep in order to be praised by their elders. But, because of this youthful exuberance, it often resulted in an “Over-G”. One time, our Operations Officer “Popeye” got a rash of frustration from the maintenance leadership. They told him the excessive number of Over-Gs are forcing their people to focus on inspections instead of preparing jets for flight.

As can be expected from our hierarchal gun-slinging leaders, I got a quick fix to this “technical” problem. (FYI, it was not a technical problem that could be solved with a simple mandate)

Popeye announced to the squadron that if anyone “Over-Gs” they would be fined $5.00 (the $5.00 rule) in the bar on Friday, and anyone that “Over-G’s” twice would spend the day grounded as a bathroom attendant. We all snickered and laughed at the prospect.

So, a couple of weeks later, I arrived in the operations part of the squadron and went into the bathroom prior to my briefing. The bathroom smelled like lavender with carefully placed soaps, fragrances, poo pourri, shaving cream around the sinks. After using the “loo” I washed my hands and turned around and Popeye handed me a towel.

I think we both started laughing as I knew what must have happened. He set the ultimatum and was the first to Over-G twice. But “he owned the crime and did his time; and did it exceedingly well.”

Great job Popeye! After his incident, the number of Over-Gs dramatically decreased equal to the increase in the admiration and respect for him. Popeye’s next assignment was as squadron commander of the world’s greatest fighter squadron.