Aircrew safety: Helmet standards in the US
Amy Gallagher asks if the new Civilian Aviation Helmet Standard has resulted in more questions than answers
In April 2019, AirMed&Rescue reported on the rotor industry’s initial response to the new Civilian Aviation Helmet Standard set forth by the interagency Office of Aviation Services (OAS), directed by Chief Keith Raley. The DOI Press Office Washington DC did not permit participation within DOI Chief Keith Raley’s office, while at the same time, the DOI press office did not provide any responses to the multiple inquiries for input to this article over the course of several months.
In April 2018, the Interagency Aviation Life Support Equipment Guide/Handbook, published by the United States Department of the Interior (DOI)-United States Forest Services (USFS), outlined the policies, procedures, and responsibilities for using ALSE during DOI-USFS aviation activities. It is designed to supplement the DOI-USFS manuals, providing detailed information as well as specific requirements. The scope of ALSE covers a broad spectrum of equipment and procedures for protecting aircrew, passengers, and support personnel involved in aviation activities, including mishap or survival situations.
Prior to revising the Handbook in 2017, however, the DOI-USFS-OAS team identified a problem with respect to helmet safety and quality within the civilian aviation market, leading to the overarching need to establish a new standard. Unfortunately, according to OAS Chief Keith Raley, a consensus on safety standards for the civilian flight helmet did not exist.
At that point, the DOI-USFS determined the solution was to identify a team of research science and technology experts who could deliver a modern, cost-effective, proven performance standard based on sound testing methodologies, scientific systems engineering and human factors subject matter expertise.
As published in the first AirMed&Rescue article on this topic, the new standard received assistance from the Southwest Research Institute (SwRI) along with the assistance from the US Army Aeromedical Research Laboratory [USAARL], that specifically referred the DOI office to their preferred standard: FNS PD 96-18.
SwRI: one agency, two roles
Allen Beavers, Research Engineer for the SwRI’s Mechanical Engineering Division, explained the company’s part in the standardization of civilian aircrew helmets: “Our role regarding the DOI standard and testing of helmets has two separate functioning roles with respect to the aviation helmet testing. Qualification testing is designed to simply identify whether a particular model of helmet meets the minimum level of protection dictated by the pertinent standard requested by our client, which includes the testing of aviation helmets to the DOI standard,” he said. “All testing in this capacity is client propriety.”
Its second role was to provide input to the DOI regarding appropriate test protocol for aviation helmets in a manner to meet a minimum set of performance levels. Beavers said: “This input has been based on input from the DOI, helmet manufacturers, and other test labs; it is not based on any specific testing of prototype helmets,” he said. “This is the primary reason that the DOI standard is based on existing or withdrawn FMVSS and military standards.” (FMVSS – Federal Motor Vehicle Safety Standards – are US federal regulations specifying design, construction, performance, and durability requirements for motor vehicles and regulated automobile safety-related components, systems, and design features.)
Chief Raley noted that while one testing methodology – ANSI Z90.1 – has been withdrawn, FMVSS 218 is still active and relevant.
Grafting a ‘new’ standard
As a result of the selected standard specifications that the DOI-USFS adopted by multiple agencies, the new DOI standard has formed into a hybrid of sorts. Furthermore, while Beavers said the new standard has been completed and available online for several months now, the standard has periodically been updated to incorporate continued feedback from various other test labs and helmet manufacturers.
During the almost 24-month timeline to secure helmet certification, the SwRI implemented seven revisions to the standard. Chief Raley commented: “The revision [s] didn’t prevent any manufacturers from testing. They chose to wait and only provided meaningful feedback in March of 2019. Additionally, the changes were relative to testing labs – not manufacturers. They had ample time to begin testing.”
As published on the DOI site, the DOI/USFS Aviation Helmet Standard 4.3 (updated 11/13/2019) requires that a helmet provides a minimum level of impact and hearing protection, and, most importantly, fits securely on the aircrew’s head in the event of an accident or incident. The standard also defines ‘aircrew’ as all those involved in the operation of a helicopter while in flight.
According to DOI Chief Raley, manufacturers and distributors can test their helmets to the DOI/USFS Aviation Helmet Standard using an ISO-certified laboratory. Those meeting or exceeding these standards can be issued a certificate of compliance by the laboratory. These helmets will be identified by the manufacturer and model type on the OAS website within 30 days of receiving the certificate.
The new DOI-USFS civilian aviation helmet standard certification, through seven revisions, has been issued to two companies: Paraclete Aviation Life Support and Helicopter Helmets, LLC.
Paraclete Aviation Life Support
Paraclete Aviation Life Support received its ISO 9001:2015 QMS certification, and earned the new DOI standard certification in February this year for its AEGIS-D Type I helmets, available in expanded sizes [S-XL], explained Carlos Andino, MBA, Market Development Director. “Our helmets, the Aspida and Aegis, already have innovative safety features such as the Kairos retention assembly,” said Andino. “We were already confident, from our testing that began in 2014, even before entering the certification process knowing that our helmets already had superior impact protection.” Andino said in March that the company’s Aspida size XXL helmet would be completed by 20 March.
The company’s greatest hurdle to certification was in the waiting, he added. “Our greatest challenge was having a non-testable standard as we waited out the 18-month revision process to the DOI’s standard, from version 1.0 to version 4.3 to get to the point where we were finally able to test against the revised standard,” explained President Scott Hedges, a retired military helicopter pilot, and former life support officer.
“The DOI chose to not pick any winners or losers, not put anyone out of business even though the new standard may be difficult for some businesses to meet,” said Andino.
Helicopter Helmets, LLC. | Evolution Aviation Helmets
According to Ron Abbott, Owner, Helicopter Helmets, LLC, an aviation safety equipment company, and worldwide distributor for the EVO helmet, located in Melbourne, FL, the Evolution [EVO] Helicopter Pilot Helmet [HPH] Type I size L has been approved, as well as the EVO 152 Type 1 and the EVO 252 Type 1, both size L, by The Impact Test Laboratory at Dynamic Research Inc and certified for compliance to meet the requirements of the DOI-USFS Aviation Helmet Standard Version 4.3. The accredited testing facility provided the certification of compliance to the DOI-USFS Aviation Helmet Standard. The EVO 152 and 252 have passed all DOI requirements to be an approved helmet under the new DOI’s Helmet Standards, confirmed Abbott.
“We started the process toward certification in May 2019 with attenuation, design approval, and impact tests, which include side impacts,” he said.
The EVO XPH and 052 are next in line for the impact testing which will finalize the requirements to be certified under DOI, followed by the XPH helmet
The EVO XPH and 052 are next in line for the impact testing which will finalize the requirements to be certified under DOI, followed by the XPH helmet, said Abbott.
“Evolution not only continues to upgrade the helmets, but continues to develop new features to make life better for the pilot or crew wearing the helmet,” he said.
The EVO is more of a ‘Rolex’ which includes a high-end design, with a lighter weight and built on precision workmanship, explained Abbott, who added that the HPH is a durable helmet, designed for easy fitting.
For the past 12 years, Abbott has added to his list of offerings for the helmet industry, including the FidLock for use in the retention system / chin strap, the Bose installation method in which Abbott patented the kit for the SPH-5, the surface adapter for the NVG mount-universal, the dual impedance selector switch and the Maxillofacial mask for the MSA Gallet.
Approved ‘non-military’ helmets
According to DOI Chief Raley (who suggested including the approved military helmets in this article) the DOI/USFS Aviation Helmets Standard Specification will provide an avenue to allow several non-military helmets to be considered for acquisition within agencies:
Abbott stated that the Gentex SPH-4B, SPH-5, 84P and 56P, as military approved helmets, are not required to be tested under the new DOI standard.
Gentex VP, Aircrew Division, Robert McCay commented: “The DOI Standard is the first industry-wide commercial helicopter helmet requirement.” He added: “The DOI Standard will improve safety for the entire industry with intent to reduce injuries and save lives.”
The Gentex HGU-56/P Rotary Wing Helmet System has been improved to support the United States Army Air Soldier Program Objective to reduce the weight and bulk of flight safety equipment
“In simple terms, the Standard requires that a helmet provides a minimum level of impact and hearing protection,” said McCay. “Most importantly, that it stays securely on the aircrew’s head in the event of an accident or incident. The Standard also defines aircrew as all those involved in the operation of a helicopter while in flight, thus ensuring the same level of protection for all aircrew onboard.”
As published on the Gentex site: “The Gentex HGU-56/P Rotary Wing Helmet System has been improved to support the United States Army Air Soldier Program Objective to reduce the weight and bulk of flight safety equipment.
. Ideal for extended mission requirements of rotary wing aircrews. The HGU-56/P Improved Rotary Wing Helmet System weighs less than the standard Gentex HGU-56/P Rotary Wing Helmet System, making it easily wearable during extended use. By utilizing this system, comfort and sustainability is greatly improved.
According to Robert McKay, “We improved our most popular rotary wing helmet system to support the US Army Air Soldier Program objective to reduce the weight and bulk of flight safety equipment for extended mission requirements of rotary wing aircrew.”
Major departures from military standards
“We believe that some of the requirements were ‘major’ changes from standard US Army requirements and test methodologies,” said Hedges. “The US Army requirements are based on research conducted on hundreds of helicopter accidents by USAARL.”
We want to see all helmets approved by the DOI/USFS Aviation Helmet Standard required to be tested
We want to see all helmets approved by the DOI/USFS Aviation Helmet Standard required to be tested, said Hedges.
Here’s why: “By combining civilian specifications from FMVSS No. 218 with the military specifications, DOI/USFS has undermined the validity of approving military helmets for use without testing against the standard,” explained Hedges.
Raley commented: “The DOI has long recognized the contributions that the military has provided to helmet design and has recognized the validity of the military standards. The problem with the military standards is they used a non-supported testing methodology ANSI Z90.1. This couldn’t be repeatable by current ISO labs that must use recognized active standards. The military helmets, especially the HGU-56/P is overwhelmingly recognized as a high-performance helmet. DOI recognizes the value of the military standards.”
The HGU-84 tech report is still available at https://www.usaarl.army.mil/pages/publications/techreports/ This link will take you to their search page and then type in 96-04 and you will get a search page result. The results are numeric starting with the earliest.
Headform and helmet size
Headform and helmet size greatly affect the total drop mass and the amount of energy imparted to the headform, which in turn, affect whether the same helmet configuration of a medium-size helmet will properly attenuate a much higher level of energy from the larger size XXL.
Additionally, as part of the DOI/USFS Aviation Helmet Standard, all sizes of helmets are required to have all seven impacts, including the lateral impacts (ear cup) conducted on each helmet using the appropriately sized headform for the size of the helmet using cold, ambient, and hot temperatures.
The military test, FNS PD 96-18 (HGU-56/P), only requires three impacts (Para 126.96.36.199) per helmet, not seven on a single helmet, and only at ambient and hot temperatures (Para 4.7.2 (4)). Additionally, FNS PD 96-18 (Para 4.7.2 (3)) only requires three Department of Transportation [DOT] headforms, sizes B, C, and D, to conduct impacts and only the sizes of helmets that fit those headforms (Para 188.8.131.52). The DOI/USFS Aviation Helmet Standard, by contrast, requires each helmet size to be tested on the appropriately sized headform.
The military, using FNS PD 96-18 (HGU-56/P, Para 4.7.3) and PS-0020 (SPH-4B, Para 184.108.40.206) only require the helmet size (M-L) using only ambient conditions corresponding to a ‘modified ANSI size C headform’ to be impacted on the ear cup, unlike DOI/USFS which requires lateral ear cup impacts using non-modified headforms during hot, cold, and ambient conditions on every size helmet.
Raley said to AirMed&Rescue: “The DOI testing methodology conforms to many other helmet manufacturing testing methodologies.”
The DOI testing methodology conforms to many other helmet manufacturing testing methodologies
Impact testing: flat anvil vs. hemisphere
Another example of a major departure is the decision to use the FMVSS No. 218 test specification to require both hemispherical and flat anvils while conducting impact testing, said Hedges, adding that US Army specifications require the use of flat anvils during impact testing, as USAARL research confirms that the primary risk during helicopter accidents simulate flat anvil, not a hemisphere.
Hedges explained further that the DOI/USFS test requires hemispherical anvil, especially during ‘hot’ conditions, which will require the change of the composite lay-up of the shell and/or the increased density of the Styrofoam impact liner [or increasing the thickness of the Styrofoam impact liner]. “This is due to the hemisphere that focuses more of the impact energy over a much smaller area than a flat anvil,” he said. “Military (Type I) helicopter helmets are designed to prevent injuries from flat anvil types of hazards, not hemispheres.”
Raley responded, stating that ‘again, we recognize the military standards and value, but could not be repeated with modern ISO labs’.
(Note: USAARL Report No. 96-04, Performance Assessment of the HGU-84/P Navy Helicopter Pilot Helmet, https://www.usaarl.army.mil/TechReports/96-4.pdf)
Different standards, same helmet part
The chin strap of the Kairos also introduced to the industry the use of the Fidlock magnetic clasp, according to Hedges. “It’s a safety element because how users wear the helmet is paramount to their safety,” he said. “By having a chin strap that is repeatedly worn properly we have designed into the helmet another element of user safety. We also brought a specific NearArc® technology to our visors, which provides optimal clarity with near-zero horizontal shift and power while maintaining ballistic protection.”
Hedges also stated that Paraclete lenses passed the more stringent MIL-DTL-43511D test, versus MIL-DTL-43511 required in the current US Army helicopter helmet.
Another major requirement and departure from the standard US Army requirements are how chin strap elongation is measured. “Again, the DOI/USFS standard is more stringent than the US Army’s,” said Hedges. “Under current US Army requirements, the amount of impact liner and comfort liner compression is measured and then is allowed to be used to reduce the total elongation measured against the standard.”
According to FMVSS No. 218 (7.3.3, 7.3.4), the liner compression is not measured separately, but rather as part of the total system elongation and is not allowed to be used to reduce the total system elongation. “This may not seem like a big deal, but when you are allowed to reduce the total system elongation, which is maximum of 1.26” @ 300 lbs, by the amount of the measured compression of the liner systems, upwards of one-third or more of the total allowed elongation, it is a very big deal in determining whether or not you will pass the standard,” stated Hedges.
Additionally, he said, the DOI/USFS reduced the US Army amount of weight required from 440 lbs to 300 lbs for measuring chin strap elongation. “They should have required 440 lbs,” said Hedges.
“One of the most significant facts based on our research and testing that strongly suggests that the US Military (Type 1) helicopter helmets that use sub-3.5-lb density Styrofoam impact liners (SPH-4B, HGU-56/P) will not pass the current DOI/USFS standard for impact protection against a hemispherical anvil,” explained Hedges.
Helmets can only protect the users if they are properly fitted and worn correctly, stated Hedges. “Make no mistake, helicopter helmets are designed to protect the user from injury in an otherwise survivable accident,” he said. Hedges stated his belief that: “There are too many operators that have been severely injured when they would have otherwise not been injured or would have suffered much less severe injuries, had their helmet not come off of their head during an accident sequence or were wearing a helmet instead of a headset. ”
FlightHelmet.com in Easton, MD began advertising a routine helmet inspection and maintenance program in early 2019. The program is designed to satisfy the helmet inspection requirements of various aviation organizations, and ensure helmets are inspected and repaired on a regular basis by experienced helmet technicians, stated FlightHelmet.com Owner Gerald Bell.
When asked about how FlightHelmet.com’s maintenance program aligned with the new DOI-USFS standard, Bell referenced sections 5.1.1 thru 5.1.5 [v4.3] of the standard which provide the criteria for inspections; section 5.1.6 which requires that approved helmets come with a user manual that includes the maintenance instructions for the helmet; and section 5.1which states: periodic inspection tasks for the helmets by the operator/user shall be sufficient to ensure they are free from all defects which would affect proper functioning in service as identified in §5.1.1 to §5.1.5, the periodic inspection intervals shall not be greater than one (1) year and the helmet shall be examined from a distance of no greater than 0.6 meters.
According to Bell, the DOI-USFS standard provides criteria to the manufacturer regarding the ease of inspection that must be met to achieve certification, but does not limit the individuals or organizations who can perform the inspection and maintenance to the original manufacturer. “In order for a manufacturer’s helmet model to be approved to the standard, they must satisfy the above criteria that says all inspections must be able to be performed by an end user, and the periodicity that they should be performed,” said Bell. “Some end users prefer not to perform their own inspections and maintenance, and that’s where FlightHelmet.com comes into the equation. We offer those inspection and maintenance services for helmets made by any manufacturer, not just our own, and those helmets may or may not be an approved DOI-USFS helmet make/model.”
When asked if FlightHelmet.com is planning to pursue testing a new helmet to the new DOI standard certification, Bell said, “That is a business decision, and we have not decided that yet. However, I am pleased to see that the DOI has written a standard as it provides an opportunity for helmet companies wishing to sell new helmets for use by DOI-USFS a path to compete for that new helmet sales business.”
Accountability factor missing
As published in the updated Handbook, the criteria for identifying each helmet is as follows: “Each helmet shall have a permanent type identification label applied to the helmet or liner that includes: manufacturer, date of manufacture, model type, and discrete size similar to the requirements in FMVSS No. 218 S5.6.111. The helmet shall be inspected to determine if the required label is present, permanent, legible, easily read, and contains the required information.”
As stated by the DOI, the helmets will include a label with the manufacturer’s details. In the event of an accident, label data may or may not be included in the National Transportation Safety Board (NTSB) report, according to Peter Knudson of the NTSB. Tracking and recording the history of use of any aviation product is not within the scope of the NTSB’s authority, he explained.
The agency’s helicopter specialists conduct comprehensive investigations looking at the survival factor aspects: crash worthiness, equipment functions and operations to determine if the crash was survivable
“The agency’s helicopter specialists conduct comprehensive investigations looking at the survival factor aspects: crash worthiness, equipment functions and operations to determine if the crash was survivable, said Knudson. “Investigators look at the effects of survivor ability and the equipment worn by pilots. If the use, non-use or overall performance of a helmet was relevant to a helicopter accident investigation, we would address it in the accident narrative or the docket.”
NTSB helicopter specialists analyze survival factors and occupant safety surrounding a helicopter accident, such as whether or not the equipment – a helmet – played a role in an accident, he added.
“Such documentation could appear in the text of the accident narrative or in supporting factual materials, which would be stored in the accident docket (available on our website: https://dms.ntsb.gov/pubdms/search/),” said Knudson.
“It is a well-proven fact that helmets provide a significant level of enhanced protection to aircrews that choose to wear them,” said Chris Martino, VP, Operations, Helicopter Association International (HAI). “Ensuring the quality and performance capability of this equipment through industry standards makes sense.”
There are countless examples across a broad spectrum of industries where product standards ensure performance, added Martino. “The forward thinking of the DOI/USFS in the development of viable performance standards for civilian aviation helmets demonstrates their commitment to the safety of the aircrews that perform their agency missions.”
The helicopter industry recognizes that a gap exists related to helmet standards. Efforts such as those seen by DOI/USFS are doubtless a good initial step to closing this gap.