Zero/Zero ejection seats vs. safe operating range.

[Randy Haskin]

Would you ever consider a belly landing in a F-15 or 18, if you have control but little or no power? Or is ejection about the only way?

Good question, actually.

If it were a case of "little or no power", probably not. Jets without power don't glide very far. The "high key" for most jets is 10,000 feet directly overhead the field, so you can imagine the amount of altitude lost during the flameout pattern.

If you have "little control"....it depends on how much control. Our tech order says that if we have the time, to perform a controllability check while at altitude to determine if decelerating to landing speeds is possible. If it is, then we'll try to land. If not...or we don't have time to do so...then find a piece of unpopulated land or water and pull the handles.

Overall, the mindset is very different than in an aircraft where there is a better glide ratio or flight controls that can work under a manual mode.

I mentioned this in the other thread, but I'll repeat it here: the decision to eject is never one that is taken lightly. Pilots don't *want* to have to get out of the airplane, even in an emergency. There are numerous human factors as to why this happens, but it results in numerous pilot deaths when -- had they decided to eject seconds or even miliseconds earlier -- they would have lived. So, the mentality of "well, I'll just send this one back to the taxpayers" is hyperbole.

[Bill Walker]

A very interesting thread. You may be interested to know that the CF has a Hornet still in their inventory with a history of 2 ejections. Both were on the runway, when it became obvious the aircraft would not stop before departing the pavement.

The aircraft is 188761. The first ejection was in 1987, during an aborted takeoff at Alconbury in the UK. This one took major repairs, at DASA in Germany. The second was a ground loop on landing on a wet runway, 19 June 2004, at Yellowknife. This one was repaired on site, and flown out. The aircraft carried special squadron markings in the summer of 2007, and you may have seen it at airshows across North America.

I wonder if the crews today know its history? Any other modern military aircraft out there with this kind of a record?

[Tom Moungovan]

Ed Lagerstrom, my shop foreman @ Edwards when I was there, told our shop about a pilot who went out on an early a.m. sortie in an F-101, had trouble & ejected. He was medically examined and judged unhurt & fit to fly. He had another scheduled test flight around 1P.M., made that one & had the same result. OK again, but a strong statement was given to him about no more flying that day. These were the old days.
Posters are correct about injuries suffered while egressing the aircraft and a great many involved the spine. Martin Baker did a mod and went to low-yield cartridges in the F4 seats in the mid 60's to try to alliviate this.
F-104 seats had rotating arms that swung up deploying webbing to prevent the arms & elbows from striking the aircraft while ejecting. They also had a foot retraction device using cables to snug the pilots feet up against the front of the seat so they'd clear during ejection.
There was a lot of talk even back in the 60's about zero-zero capability. I saw movie footage of a test that unfortunately resuled in a fatality when the pilot delayed so long in making the decision to eject that when he finally did, the aircraft was just contacting the ground. The seat fired, but the roll of the aircraft sent the seat out sideways & he hit the ground before the parachute could deploy & was killed.

[Jack Cook]

a ground loop on landing on a wet runway,

sounds a bit like Capt Kleeman's fatal F-18 accident at Miramar a few years back.

[ktst97]

There was a lot of talk even back in the 60's about zero-zero capability. I saw movie footage of a test that unfortunately resuled in a fatality when the pilot delayed so long in making the decision to eject that when he finally did, the aircraft was just contacting the ground. The seat fired, but the roll of the aircraft sent the seat out sideways & he hit the ground before the parachute could deploy & was killed.

I witnessed a crash at Etain, France in '63 or '64 in which an F-100 pilot out of a USAF base in Germany was attempting to get to Etain AFB for an emergency landing. From the transient ramp, we could see the F-100 trailing significant amounts of smoke. Unfortunately, the plane failed making it to our base, by about a quarter mile. The pilot was killed under circumstances same as those quoted above.

[Bill Greenwood]

Quite a trend since the early days. At the start of WWI pilots did not even have chutes, they were considered a little sissy and would give guys the wrong idea. But the planes were light with big wings, and with any good controls working could be force landed power off and stop in a couple of football fields length. They really were "KITES".

In WWII, the planes were bigger, faster, but still were often landed in fields. And they had chutes. In the Battle of Britain 60% of pilots were saved by parachute, and that even though many were on fire or wounded.

Now we have gone to the other end, the planes are heavy fast, complex, and don't glide well to a forced landing and if they get there is a big impact. But they have ejection seats that can give a pilot a 2nd chance to survive.

[Dave Downs]

duplicate

Last edited by Dave Downs on Thu Dec 11, 2008 1:12 pm, edited 1 time in total.

[Dave Downs]

I have a tape of various military aircraft in 'difficult' circumstances given to me by a friend in military aviation years ago. Some of the footage is well known, such as the 'Sabre Dance' which shows an F-100 at a high angle of attack just off the runway surface and the pilot goes in and out of 'burner in an attempt to regain control - that clip gives me the creeps every time I see it because you just know how it's going to end.

There are 2 scenes with ejection seats that are memorable.

The first is an A-6 that bolters, then sinks down to within a few feet of the water - the crew (2) punch out, the aircraft accelerates and flies away, pilotless......

The second is an F-16, the view seems to be through the HUD; the plane is on the runway with what seems lke locked brakes, sliding sideways. The aircraft comes to a stop at an angle to the runway, and the pilot is seen landing in his 'chute in front of the plane.....

[Bill Walker]

a ground loop on landing on a wet runway,

sounds a bit like Capt Kleeman's fatal F-18 accident at Miramar a few years back.

I think this one was a lot tamer. The aircraft was Category D, "repairable on site". It came to rest upright, just off the edge of the pavement. You can't realy blame the pilot for leaving when he could. He was heading for the edge of the pavement sideways with the engines still hot and winding down, probably thinking about the first wheel off digging into the wet dirt. The gear cold have collapsed, leading to a roll over and maybe a fire.

[jet1]

First off, realize that all that a "zero/zero" seat "guarantees" you is one swing in the chute before your boots hit the ground. Basically the parachute will fully inflate, which starts the pendulum moment of the pilot under it, and as the pilot swings back to the center of the chute area he will impact the ground. It's something like 1/2 to 1 second under an opened canopy. That is not a very safe landing, as after one swing after opening, the parachute hasn't really decelerated you as much as it's going to.

More important to this discussion, the capability of "zero/zero" seats is diminished greatly by a sink rate or downward vector. The #1 most important rule that we brief before every flight is "get out before a sink rate develops". Once the flightpath/flight vector is downward, it greatly shrinks the survivable envelope of an ejection.

Ejection seats are NOT magic by any means, and even the really good ones have pretty significant limitations to the flight envelope.

it is guaranteed to HURT!

[JDK]

Maybe here's a place to tip the hat to one of the bravest individuals in aviation history, who put his body on the line to save numerous lives afterwards - let's hear it for Fitter (not pilot) Bernard Lynch.

Martin-Baker started to investigate ejection seats from 1934 onward, several years before Germany (1938) and Sweden. The company concluded that an explosive-powered ejection seat was the best solution. Studies found the limits of upward acceleration that the human body could stand and experiments were conducted using a volunteer, Bernard Lynch, who was a fitter at the factory. The first seat was successfully live tested by Lynch on 24 July 1946, who ejected from a Gloster Meteor travelling at 320 miles per hour (510 km/h) IAS at 8,000 feet (2,400 m) over Chalgrove Airfield in Oxfordshire[1].

http://en.wikipedia.org/wiki/Martin-Baker

The first live ejection was made on 24th July 1946. Mr Bernard Lynch ejected himself from the rear cockpit of a specially modified Meteor 3 at 320 mph IAS at 8000 ft. The whole system worked successfully. Mr. Lynch made a perfect landing and subsequently made a further 30 ejections.

http://www.martin-baker.com/Products/Ej ... Mk--1.aspx

...and he continued in that job - rather him than me! Martin Baker are still using Chalgrove, BTW.

First test aircraft for dummy ejections was an ex-USAAF used Boulton Paul Defiant.

It's notable also that even today, Martin Baker are using the W.W.II technology Gloster Meteor as a flight testbed for their seats - not because of any sentimental reasons, but because it's still the best for the job. (Apart from Coulson's Martin Mars, I can't think of an older 'high performance' military type still in use for over 1/2 a century later, in a secondary role...)



http://www.martin-baker.com/History/Milestones.aspx

[BigGrey]

Are all the ejection seats currently in use vertical seeking or just certain models in certain aircraft?
I had a roommate who was a Marine fighter pilot in the 70's. He said he was offered Harriers after graduation but declined as they were known as Marine drops. He said part of the problem was that by the time the pilots decided to eject they were out of the safe envelope and with the non-vertical seeking seats they pretty much just hit the ground.

In videos of Russian pilots ejecting it seems they use vertical seeking seats also.

Les

[warbird1]

Are all the ejection seats currently in use vertical seeking or just certain models in certain aircraft?

No. Only the more recent aircraft are. Old planes like the T-38 still use non-vertical seeking ejection seats.

[Randy Haskin]

I'm gonna have to go to my bookshelf and check for sure, but the ACES II seat (the one in the F-16, F-15, and A-10) is not "vertical-seeking".

It has a rocket connected to a gyro that ensures the vector of the seat is straight (and not in a circle or off to one side), but it does not seek to right itself with respect to the horizon. In fact, I'm not really sure how a seat would be able to know where the horizon is located to be able to "seek" it.

[CAPFlyer]

The ACES II has multiple settings, but I've not heard of anything that would self right using the motor alone. I know that the B-1B seats are setup with the motors on a gimbal that allows them to "seek" a different vector on departing the aircraft to ensure that at low speeds all 4 seats head away from each other. This is done via programming of the rocket gyroscope.

As for how a seat "seeks" vertical flight, there are various methods, but the primary one used by the Russians is simply stabilizing arms that makes the seat "fly" upright and thus finding vertical. Another method is simply weighting the seat heavily to the bottom leading the seat to want to put its bottom down much more heavily and resulting in an apparent "seeking" of vertical.

I believe that there were tests done on a seat with an internal gyroscope and reaction motors that once the ejection sequence was initiated and the seat was clear would "guide" the seat upright. I believe this was also a liquid fueled system (with its inherent problems), so I doubt that it would have been feasible.