6/17/21 

Pilot/Controller Glossary 

J 

JAMMING

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 Denotes emissions that do not mimic 

Global Navigation Satellite System (GNSS) signals 
(e.g., GPS and WAAS), but rather interfere with the 
civil  receiver’s ability to acquire and track GNSS 
signals.  Jamming can result in denial  of GNSS 
navigation, positioning, timing and aircraft depen-
dent functions. 

JET BLAST

−

 The rapid air movement produced by 

exhaust from jet engines. 

JET ROUTE

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 A route designed to serve aircraft 

operations from 18,000 feet MSL up to and including 
flight level 450. The routes are referred to as “J” 
routes with numbering to identify the designated 
route; e.g., J105. 

(See Class A AIRSPACE.) 
(Refer to 14 CFR Part 71.) 

JET STREAM

−

 A migrating stream of high-speed 

winds present at high altitudes. 

JETTISONING OF EXTERNAL STORES

−

 Air-

borne release of external stores; e.g., tiptanks, 
ordnance. 

(See FUEL DUMPING.) 

(Refer to 14 CFR Part 91.) 

JOINT USE RESTRICTED AREA

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(See RESTRICTED AREA.) 

JUMP ZONE

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  The airspace directly associated with 

a Drop Zone. Vertical and horizontal limits may be 
locally defined. 

PCG J

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