Attachment 8
JET BLAST EFFECTS
A8.1. Contents. Jet blast affects various operational areas at an airport. Personnel safety is a major
concern in terminal, maintenance, and cargo areas.
A8.2. Considerations. The effects of jet blast are far more serious than those of prop wash and must be
considered when designing aircraft parking configurations for all military and civil aircraft. These high
velocities are capable of causing bodily injury to personnel, damage to airport equipment, or damage to
certain pavements and other erodible surfaces.
A8.2.1. Blast Temperatures. High temperatures are also a by-product of jet exhaust. The area exposed
to hazardous high temperatures is typically smaller than the area subjected to hazardous blast
velocities.
A8.2.2. Blast Velocities. Blast velocities greater than 48 km/h [30 mph] can cause loose objects on the
pavement to become airborne and cause injury to personnel who may be a considerable distance
behind the aircraft. The layout of aviation facilities must protect personnel from projectiles.
A8.2.3. Minimum Clearances. The minimum clearance from the rear of a jet operating at military
power to dissipate the temperature and velocity to levels that will not endanger aircraft personnel and
damage other aircraft is referred to as the safe distance. Safe distances are discussed in paragraph
A8.5.
A8.2.4. Engine Blast Relationship. Each jet engine has its own footprint of temperature and velocity
versus distance. Jet blast relationships for Army, Air Force, and selected civil aircraft may be obtained
from the sources listed in Attachment 7. The relationships are in graphical format showing velocity
versus distance and temperature versus distance at various power settings. The planner/designer
should obtain the jet blast relationship when the effects of jet blast could create a hazardous condition
for personnel and equipment.
A8.3. Protection from Jet Blast Effects:
A8.3.1. Blast Deflectors. Equipment such as blast deflectors may be required at locations where
continued jet engine runup interferes with the parking or taxiing of aircraft, the movement of vehicles,
and the activities of maintenance or aircraft personnel. Additional information on jet blast deflectors is
presented in Attachment 9 of this manual.
A8.3.2. Unprotected Areas. Airfield unprotected areas which receive continued exposure to jet blast
can erode and cause release of soil, stones, and other debris that can be ingested into jet engines and
cause engine damage.
A8.3.3. See USAF Engineering Technical Letter 01-5, Jet Engine Thrust Standoff Requirements for
Airfield Asphalt Edge Pavements, for minimum distances from the rear of jet aircraft to the edge of
adjacent asphalt pavements.
A8.4. Noise Considerations. Protection against noise exposure is required whenever the sound level
exceeds 85 dB(A) continuous, or 140 dB(A) impulse, regardless of the duration of exposure.
A8.5. Jet Blast Requirements:
A8.5.1. Parked Aircraft. Criteria in AFH 32-1084, Facility Requirements Handbook, state that a
minimum clearance is needed to the rear of an engine to dissipate jet blast to less than 56 km/h [35
A8-1
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