Balloon Life,April 2000

50

It’s nighttime thirty years ago over North
Vietnam.A U.S.pilot seesaflashfrom
below;suddenly hiscockpitalarmstarts
buzzing.Theflamefromarapidlyap-
proachingtelephonepole-sizedmissile
illuminatesatrailofsmoke.Thepilot
desperately tries to evade the SAM, but to
no avail. Heejectsasshrapnelbeginsto
ripthroughthe plane’sfuselage.Hede-
scendsincold silence, a white lifesaving
canopy above and a dark, hostile, canopy
of jungle below.
Inthelate1960sandearly1970s
numerousU.S.pilotsejectedintothe
clutchesoftheenemy.Capturewaited
below, but what alternative did theejected
pilothave?Inanattempttogivepilots
another option, the Air Force hired Raven
Industries, now Aerostar International, to
assist in designing an ejection system that
wasbothparachute and aircraft.
ThePilotAerialSurviv alSystem
(PASS), according to a 1972 patent issued
totheUSAF, includeda typicalconical
parachute tosupporta pilotandejection
seat.Positionedabovetheparachute’s
canopywasaballo onenvelop e.The
balloon’smaininletwassecurelycen-
tereddirectlyoverthecanopy’scentral
vent, allowing the balloon tofill with air
passing over and throughthe canopy.
A miniatureburnerwassecuredto
theenvelopewithbracketsandsuspen-
sionlines, whichkeptit centeredwithin
theballoon’smaininlet. Tooperate the
burner, the pilot opened a tank of propane.
The pressurized fuel traveled up through
ahose to the burner. Once the fuel reached
theburner,it immediatelypressurizeda
chamber,whichtriggeredafiringpin
within an igniter. The firing pin lit a pilot
light,whichinturnigniteda3,000,000

Aerial Life Saver

by Larry Nelson

BTW/hr flame fueled by propane that had
beenvaporized via a central burner coil.
The flame added heat to the balloon enve-
lope causing the pilot tostopdescending
or quicklyascend out of range of ground
fire.
Once at a safe altitude, the balloon’s
stealthyradarsignaturewouldassistin
evading missiles, as long asthey weren’t
heat seeking. PASS would act as an aerial
life preserverallowingthepilottofloat
out ofrangeof danger untilhe couldbe
literallyscoopedoutoftheskybyan
aircraft riggedwith anylonpick-upline
and hooks. These giant fishing lines were
standardequipmentfortheAirForce’s
AerialRefuelingandRetrievalSquad-
rons duringthe Vietnam War. The aerial
retrievalcapabilityof PASS wasn’tjust
theoretical,itwasactuallytested.Ac-
cordingtoJimWinker,aformer Raven
employee,“Ravensuccessfullyaccom-
plishedanumberofdummydropsand
mid-air pick-upswithPASS.”
WhathappenedtoPASSandwhy
haven’t we seen it in use? Is it classified?
Wasitabandoned?Itappearstobethe
latter, says Winker “When the project was
75 percentcomplete,andrefinementsto
fit the prototype in anejectionseat were
well along, the project was suddenly can-
celled by the Air Force.” As intriguing as
theconceptwas,itappears the bulkand
volatilityofpropanerequiredbyPASS
wasunwelcome in a fighter cockpit.

The U.S. Military’s interest in using balloon technology
didn’t stop with Ed Yost’s Office of Naval Research
contract in 1960

Above left: Patent design for a self-in-
flating balloon envelope over a deplo yed
parachute.
Below left: Patent design for the burner
mechanism of th e ejection seat balloo n
system.