John M. White

Can You Safely Eject From An SR-71 At Speed And Altitude And Survive?

Jun 2, 2023

The Lockheed SR-71 Blackbird is a long-range, high-altitude, Mach 3+ reconnaissance aircraft that was operated by USAF and NASA pilots.

Developed during the 1960s by Lockheed's Skunk Works, it was an updated version of the Lockheed A-12 recon aircraft.

It was normally operated at an altitude of 85,000 feet and speeds above Mach 3.

But, what if something went wrong?

The following article was published on the Facebook Page Habubrats SR-71, and for those of us who love David Clark headsets, this impresses us even more.

The SR-71 Flight Ejection System

The SR-71 ejection seat was usable from zero speed and altitude (a zero/ zero ejection seat) to the maximum speed and altitude of the aircraft (Mach 3.45+, and nearly 100,000 feet of altitude).

The seat was a rocket-propelled, upward-ejecting unit. Most people believe an ejection at 2,000 miles per hour would rip your body apart.

However, the air is so thin at 80,000+ feet that the actual "q" forces (decelerating g-forces) when your body first hits the airstream are a lot less than an ejection from a T-38 at 500 miles per hour at sea level.

The 7-Layer full pressure suit, made by David Clark, is designed to absorb the forces of ejection and provide pressurization to keep the ejectee alive during descent.

To eject from the SR-71, you reach between your knees with both hands crossed and give a sharp, upward tug on the seat’s large D-ring. To keep your arms tucked in tight to your body, crews were taught to hold on to the ejection D-ring as the seat fired from the aircraft.

The first and most important event after pulling the D-ring was the canopy ejecting from the cockpit.

Unlike most high-performance jet aircraft with ejection seats, you cannot eject through the SR-71 canopy.

After the sharp tug on the D-ring, the canopy unlocked and was thrust free from the aircraft.

To preclude ejecting into the canopy, there was an interlock device that wouldn’t allow the seat to eject until the canopy was first removed. So if the seat didn’t fire after pulling the D-ring, the procedure was to reach the left side of the seat and pull the yellow canopy jettison T-handle, an alternate means of removing the canopy.

If the canopy was not gone by then, the pilot would manually open the canopy locking lever and hope cockpit pressurization would push it off.

In case the D-ring initiator between your knees didn’t fire, a second ejection T-handle, also located on the left side, could be pulled to initiate an ejection.

However, the D-ring must have been pulled first in order for the T-handle to be operative. When the secondary T-handle was used, the seat catapult fired immediately, without regard to the canopy being on or off . . . and that could ruin your day!

Except for a small red light on the RSO’s instrument panel that was illuminated with the brief but attention-getting phrase “PILOT EJECTED” when the pilot jumped out, the front- and rear-cockpit ejection sequences were independent of each other.

After pulling the D-ring, there was a 0.3-second delay to remove the canopy, and then a catapult gas charge was fired to initiate seat ejection from the cockpit.

Stirrup cables attached to the heels of the flight boots would pull the legs back to the front of the ejection seat to prevent any accidents with the legs while the seat was leaving the cockpit.

The gas charge had a duration of 0.15 seconds, sufficient to raise the seat above the canopy sills, at which point a wire lanyard attached to the floor of the cockpit was pulled, igniting the seat’s rocket motor.

The rocket motor provided sufficient thrust and duration (0.5 seconds) to eject the seat approximately 300 feet above the aircraft.

Although the ejection seat was certified for zero/zero capability, the odds of a successful ejection increased as altitude and airspeed increased, which gave the parachute sufficient time to fully deploy. To aid in low airspeed and/or low-altitude ejections, the parachute incorporated an extraction gun that fired a metal slug. The .75 (Corrected - Paper copy says .75 pound, not 25 pounds, other documents say 13 ounces) pound solid metal slug attached to the parachute was fired by the extraction gun, pulling the 35-foot-diameter parachute into the airstream for the immediate opening of the quarter deployment shroud, which is designed to prevent the parachute canopy opening too suddenly and shredding.

In a low-altitude ejection (below 15,000 feet), pressure-actuated (aneroid) initiators cut your foot retraction cables stirrups via an explosive guillotine, disconnects your lap belt and shoulder harness, and activate the seat-man separator, a sling the pilot/RSO sits on, pushing them free of the seat.

In a high-altitude ejection (above 15,000 feet), you remain strapped and locked into the seat during the free fall down to 15,000 feet.

If you ejected from higher altitudes up to 80,000+ feet, the pressure suit inflates immediately via the aneroid suit controller, emergency oxygen is supplied from cylinders in the seat kit, and a battery heats the suit’s helmet faceplate, allowing you to see outside.

A stabilizing 6.5-foot-diameter drogue chute attached to the top of the ejection seat keeps the seat (and you) from tumbling during the long free fall (about 7 minutes) down to approximately 15,000 feet.

Once below 14,900 feet, the survival kit deploys on a 25-foot lanyard with a survival kit rucksack and a life raft.

If the pilot/RSO lands in salt water, the life preservers automatically deploy.

An SR-71 at altitude and speed racing across the globe.

The SR-71 Speed Check Story

This is the story as told by Major Brian Shul, USAF.

There were a lot of things we couldn't do in an SR-71, but we were the fastest guys on the block and loved reminding our fellow aviators of this fact. People often asked us if, because of this fact, it was fun to fly the jet.

Fun would not be the first word I would use to describe flying this plane. Intense, maybe. Even cerebral.

But there was one day in our Sled experience when we would have to say that it was pure fun to be the fastest guys out there, at least for a moment.

It occurred when Walt and I were flying our final training sortie. We needed 100 hours in the jet to complete our training and attain Mission Ready status.

Somewhere over Colorado, we had passed the century mark. We had made the turn in Arizona, and the jet was performing flawlessly. My gauges were wired in the front seat, and we were starting to feel pretty good about ourselves, not only because we would soon be flying real missions but because we had gained a great deal of confidence in the plane in the past ten months.

Ripping across the barren deserts 80,000 feet below us, I could already see the coast of California from the Arizona border. I was, finally, after many humbling months of simulators and study, ahead of the jet. I was beginning to feel a bit sorry for Walter in the back seat.

There he was, with no really good view of the incredible sights before us, tasked with monitoring four different radios. This was good practice for him for when we began flying real missions when a priority transmission from headquarters could be vital.

It had been difficult, too, for me to relinquish control of the radios, as during my entire flying career, I had controlled my own transmissions. But it was part of the division of duties in this plane, and I had adjusted to it. I still insisted on talking on the radio while we were on the ground, however.

Walt was so good at many things, but he couldn't match my expertise at sounding smooth on the radios, a skill that had been honed sharply with years in fighter squadrons where the slightest radio miscue was grounds for beheading.

He understood that and allowed me that luxury.

Just to get a sense of what Walt had to contend with, I pulled the radio toggle switches and monitored the frequencies along with him.

The predominant radio chatter was from Los Angeles Center, far below us, controlling daily traffic in their sector. While they had us on their scope (albeit briefly), we were in uncontrolled airspace and normally would not talk to them unless we needed to descend into their airspace.

We listened as the shaky voice of a lone Cessna pilot asked Center for a readout of his ground speed. Center replied: "November Charlie 175, I'm showing you at ninety knots on the ground."

Now the thing to understand about Center controllers was that whether they were talking to a rookie pilot in a Cessna or to Air Force One, they always spoke in the exact same calm, deep, professional tone that made one feel important.

I referred to it as the " Houston Center voice."

I have always felt that after years of seeing documentaries on this country's space program and listening to the calm and distinct voice of the Houston controllers, all other controllers since then wanted to sound like that, and that they basically did.

And it didn't matter what sector of the country we would be flying in; it always seemed like the same guy was talking. Over the years, that tone of voice had become somewhat of a comforting sound to pilots everywhere.

Conversely, over the years, pilots always wanted to ensure that, when transmitting, they sounded like Chuck Yeager or at least like John Wayne. Better to die than sound bad on the radio.

Just moments after the Cessna's inquiry, a Twin Beech piped up on frequency in a rather superior tone, asking for his ground speed.

"I have you at one hundred and twenty-five knots of ground speed."

Boy, I thought, the Beechcraft really must think he is dazzling his Cessna brethren.

Then out of the blue, a navy F-18 pilot out of NAS Lemoore came up on frequency. You knew right away it was a Navy jock because he sounded very cool on the radio.

"Center, Dusty 52 ground speed check".

Before Center could reply, I was thinking to myself, hey, Dusty 52 has a ground speed indicator in that million-dollar cockpit, so why is he asking Center for a readout?

Then I got it; ol' Dusty here is making sure that every bug smasher from Mount Whitney to the Mojave knows what true speed is. He's the fastest dude in the valley today, and he just wants everyone to know how much fun he is having in his new Hornet.

And the reply, always with that same calm voice, with more distinct alliteration than emotion: "Dusty 52, Center, we have you at 620 on the ground."

And I thought to myself, is this a ripe situation, or what? As my hand instinctively reached for the mic button, I had to remind myself that Walt was in control of the radios. Still, I thought, it must be done - in mere seconds, we'll be out of the sector, and the opportunity will be lost.

That Hornet must die and die now. I thought about all of our Sim training and how important it was that we developed well as a crew and knew that jumping in on the radios now would destroy the integrity of all that we had worked toward becoming. I was torn.

Somewhere 13 miles above Arizona, there was a pilot screaming inside his space helmet.

Then, I heard it.

The click of the mic button from the back seat.

That was the very moment that I knew Walter and I had become a crew. Very professionally and with no emotion, Walter spoke: "Los Angeles Center, Aspen 20, can you give us a ground speed check?"

There was no hesitation, and the replay came as if it was an everyday request. "Aspen 20, I show you at one thousand eight hundred and forty-two knots across the ground."

I think it was the forty-two knots that I liked the best; so accurate and proud was Center to deliver that information without hesitation, and you just knew he was smiling.

But the precise point at which I knew that Walt and I were going to be really good friends for a long time was when he keyed the mic once again to say, in his most fighter-pilot-like voice: "Ah, Center, much thanks, we're showing closer to nineteen hundred on the money."

For a moment, Walter was a god. And we finally heard a little crack in the armor of the Houston Center voice when L.A. came back with, "Roger that Aspen, Your equipment is probably more accurate than ours. You boys have a good one."

It all had lasted for just moments, but in that short, memorable sprint across the southwest, the Navy had been flamed, all mortal airplanes on freq were forced to bow before the King of Speed, and more importantly, Walter and I had crossed the threshold of being a crew.

A fine day's work.

We never heard another transmission on that frequency all the way to the coast.

For just one day, it truly was fun being the fastest guys out there.

I hope you enjoyed this trip through some of the history of aviation.

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Until next time, keep your eyes safe and focused on what's ahead of you, Hersch!

 

 

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