Flight Helmet
Flight Helmet is also known as a 'bone dome'. It is a special type of helmet primarily worn by military air crew.
A military flight helmet, besides providing head protection serves as a mounting platform for display visors, night vision goggles, oxygen mask and radio telephony that improve pilot performance during a flight or a mission.
However, there system may increase the potential for neck injury due to excess of head supported mass and altered combined head and helmet system center of gravity, while increasing the moment at the head joint neck.
In present study, a 50th %tile Anthropometric Test Dummy (ATD) head was developed to asses mass properties of mid size helmets of Mirage, Su-30, Mig21 (LWI) and Gallet assembly on a Trifilar Pendulum. The mass of the ATD head was 3.33 kg and CG from head anatomical origin was (0.28, -0.01, and 1.41cms). The mass of the helmets under study varied from 1.61 to 2.54 kg. The X and Z CG coordinates were between -0.04 to 0.85 cms and 2.45 to 3.22 cms respectively. The neck torque at C7/T1 juncture due to helmet weight and X coordinate CG shift varied from 29.24 to 78.40 N-cms. The mass moment at head neck joint was between 19.18 to 38.43 Kg-cm. None of the helmets breached the CG shift limit of the Knox-Box criteria. However, a neck torque value above 78 Ncm for Gallet assembly could adversely affect the wearer’s ability to identify and track targets and in addition could increase the neck fatigue under long duration whole body vibration (WBV)
A Flight helmet can provide :
Impact protection to reduce the risk of head injury (e.g in the event of a parachute landing) and protection from wind blast (e.g. in the event of ejection).
A visor to shield the eyes from sunlight, flash and leaser beams.
Noise attenuating, headphones and a microphone (except when include in a mask).
A helmet mounted display for night vision goggles or helmet (so the aircraft knows where the pilot is looking).
Comfort, including the weight, center of gravity and provision for cooling and ventilation.
Compatibility with an oxygen mask.
History of Flight helmets
Gentex SPH-5 helicopter helmet
Modern US Army apache helmet
British leather flying helmet from 1918
Soviet MIG-25 pilot helmet of the 1980s
Type B-6 winter flying helmet with A-9 oxygen mask, WW2 vintage
In the first day of aviation the leather helmets used in motor-racing were adopted by pilots as head protection. The initial design of early leather flying was adapted during the 1930s to become the type B helmet which enabled the external attachment of radio earphones oxygen masks and removable goggles to protect pilots eyes from the elements.
By the World War II, an oxygen mask was added to the equipment as planes flew higher where thinner air required a breathable air supply to the pilots and crew. After World War II into the Korean War, the leather headpiece was gradually replaced with a hard helmet needed as head protection during bailing out (and later with high velocity ejection). Also, goggles were replaced by a visor that was incorporated to the helmet and tinted to protect against sun. Current head gear (appears after the Vietnam War) also includes communications equipment (head set and microphones) to let pilots communicate with ground operations and their crew.
