Why do American Helicopters not have ejection seats or some form of ejection system?

Question

In Russia there is the Kamov Ka-50 which is a helicopter with a ejection seat that blows off its rotors before the pilot ejects. I was wondering why here in America we Don't have some form of similar ejection system to increase the safety of our helicopter pilots.

Answer 1

Because it was decided on balance that it was not worth it during the design phase of all systems currently in use.

As a starting point, the numbers here suggest that at low level ejection seat survival is around 50%, with helicopters rarely operating at anything other than low level. So at first order approximation fitting an ejector seat will only save 50% of the pilots who use it, and survivors will often suffer serious spinal or limb injuries.

If it is fitted, it needs to be able get the pilot out of the cockpit. For fixed wing aircraft they often either shatter the canopy, or just fire through it but for a gunship helicopter the cockpit is armored and will need some sort of fairly complicated removal system, or a seat that can fire THROUGH the armor.

The rotors also need to be removed. Ideally the main rotor assembly is made very robust, especially for aircraft getting shot at. In this case it needs deliberate weak links with explosive charges fitted, probably up in blades where signals need to get from fixed airframe into rotating shafts. Loosing a blade because weak link or associated charge/wiring was damaged is not desirable.

It is really important a partial activation is avoided (seat fires while rotors or canopy still present, or rotor fires but seat does not get message so aborts). This is also relevant for fixed wing aircraft but all the needed systems are either in the seat or adjacent canopy area (and a canopy failure may not prevent system operating, just make injury more likely). If the pilot is healthy enough to trigger an eject there are good odds the seat they are sitting in is also OK.

For a helicopter system the most likely reason to be ejecting is damage to rotor or engine. So we need to design a system that gets the needed signals to the rotor assembly, and back to confirm it triggered despite damage to the area. This presumably involves multiple redundant links and some sort of voting scheme that will be complex to design and maintain. Making it wireless would solve the damage to wiring problem but allow a remote hack to crash all your helicopters!

Then we have the inverse situation, helicopter with this system has a minor accident and hits the ground. The ejector system will need a substantial number of pyrotechnics, and may have systems to retain the pilot during ejection, this may hinder pilot escaping from the crash and mean that if pilot does have issues escaping they are sitting on top of a large amount of possibly damaged explosives. Canopy jettison or seat fire while crew or rescue team partially inside cockpit is also highly dangerous.

These issues also apply to servicing, where all explosive charges need to be safed during work and then re-armed prior to flight, especially those capable of clearing an armoured canopy or dismantling the rotor assembly.

Currently the focus seems to be allowing the pilot and crew to survive a crash, which has the advantage of generally also working for hard landings and other intermediate incidents where an ejection seat is very much an all or nothing deal that guarantees loss of aircraft and most likely permanently injure the crew.

A final darker aspect is survival post activation, given that helicopters are often operating very close or on top of hostile forces. Going down inside an armoured cockpit from 50 meters may be safer than hanging under a parachute at 500 meters against a force that considers bailed out pilots eligible targets.

None of this means ejector seats are will never exist for helicopters other than ka-50, just that not fitting them will often make more sense. An example case where one might show up is a human sized multi rotor, where firing up is much easier and auto rotation to safe landing post engine failure much harder to engineer.