Home

IT&S Group

_CAPS^TM _{and Stall/Spin}
   
Probably no technology that Cirrus has introduced has been more revolutionary to the aviation industry than CAPS (Cirrus Aircraft Parachute System). Certainly none has been more controversial.

A discussion of CAPS can strike at the heart of why many of us become pilots: we learn to rely on ourselves; we are taught from the beginning to deal with equipment failure; we absorb expressions like, “Superior pilots use their superior judgment to avoid using their superior skill.” We are uncomfortable with the idea of needing help, of getting in so far over our heads that a parachute need ever be contemplated.

There were similar reactions in the military to ejection seats. That discussion ended decades ago and few would question them today. The same has happened with CAPS in recent years. Today, CAPS has been accepted by Cirrus owners as an immensely valuable asset. Over twenty people have been rescued in 12 uses from situations including in-flight incapacitation, spatial disorientation, careless maintenance, and other loss of control incidents.

Despite some suggestions to the contrary, CAPS was an integral part of the Cirrus SR20 development from initial conception. Cirrus Co-founder Alan Klapmeier was inspired after surviving a mid-air collision early in his flying career. He wanted the SR20 to have some form of life saving device for when the pilot lost control of the airplane. Even in the mid-nineteen nineties, Cirrus saw parachutes proving themselves in the ultra-light arena and ready to be applied to heavier airplanes.


During CAPS development a prescient accident investigator noted, “…we will have a pilot to interview and an airplane to look at and we will discover causes [for accidents] we never knew existed.” He was right. CAPS has saved lives in such varied situations as :
  

Why Cirrus works so hard at spin prevention
   
Modern production airplanes are, in general, not tested or certified for spins.

Aerobatic designs such as Extra and Sukhoi products are, of course, certified for spins – but the mainstream general aviation four-seat designs such as Cirrus, Cessna (182, 350/400, etc), Diamond, Mooney, Piper etc. are not certified for spins. Few 4-seat designs have ever been tested or certified for spins.

“The spin” is a subject that often raises strong emotions. Some embrace it with an almost-religious fervour; others see uncharted land – “Here be Dragons.” The reality is simple in principle (one wing is flying, the other stalled) but subtle differences in aircraft design can create very different entry and recovery characteristics.

For most pilots recognizing the early stages of a spin, or recovering a developed spin, is unlikely in any kind of airplane. Not necessarily because of airplane characteristics but because a generation of pilots have not been required to receive training in spin recognition or recovery.

At Cirrus, our focus on spins is about prevention.

From a general aviation (travelling A to B) point of view there is no reason to look at spins as anything but a “loss of control.” Spins were eliminated from basic flight training three decades ago; recovery from a developed spin is long gone from certification tests; FAA data suggests less than 3% of inadvertent spins are ever recovered (regardless of the airplane’s capabilities), and probably none at low altitude.

In short, modern general aviation airplanes are not certified for spins, nor are pilots equipped to recover them.
  

Spin Prevention
   
Cirrus chose, in the very earliest stages of designing the SR20 to take on the challenge: to minimise the risks associated with inadvertently stalling an airplane. The approach chosen was to employ wing technology developed by NASA reducing the potential for spin entry after an inadvertent stall. The most visible aspect is the discontinuous leading edge dividing the wing into distinct parts.
  
Passive technology like this is highly regarded in safety circles since no skill or training is needed to gain the benefits. In the automotive world “traction control” is reported to reduce (single vehicle) accidents up to 67%. And the drivers involved never knew.
  
At the time Cirrus was not the only company looking at this approach: The then Lancair Company used this technology on the Columbia 300 (later, with an avionics change, the Columbia 350). The now Cessna 350 still has the benefit of this technology.
  
It was clearly understood by NASA, Cirrus, Lancair and FAA engineers that these features could affect spin recovery. The challenge for Cirrus, Lancair and the FAA was that a new certification environment would be needed. FAA engineers accepted the challenge, worked with Cirrus and Lancair, and used their ELOS (Equivalent Level of Safety) authority to develop new standards that accomodated both the Cirrus line of (SR20/SR22) airplanes and the Lancair/Columbia/Cessna 300-series.
  
In the Cirrus case CAPS was being developed independently. Combined with enhanced stall characteristics the FAA found that the whole package was potentially much safer than traditional standards. The "ELOS" was a very straightforward alanlysis: beyond any other discussion CAPS was a way to deal with the off-chance that a spin was allowed to develop. All understood that pilot skill could not be relied upon.
  
   

Was this all necessary ?
   
Opinion: No, the Cirrus would have been certified anyway:
The European authorities (initially JAA, later EASA) when first evaluating the Cirrus SR20 agreed with the principles of the FAA/ELOS approach but had some further questions. A series of spins was performed on their initiative. While not a complete formal program they reported no unusual characteristics.

Cirrus: Yes it was necessary: Regardless of anything in the spin area, future designs (from Cirrus and others) need to disregard spins:
The fact remains that a generation of pilots has not received spin training – and from the record of prior generations it wouldn’t matter if they had. Cirrus continues to go forward with aircraft designs that meet these higher “passive safety” standards regardless of the implication for spin recovery; and is committed to CAPS as a means to recover from all “loss of control” situations – including spins.

Search :