Repair Station - Fix It Right

Balloon Life,April 2000

REPAIR STATION

by Alan Sanderson

Fix It Right

WhoNeedsSurprises?
Whenyou take a balloonintoa repair station for repairs or
an annual inspection, you may find that more repairs are required
thanyouhadexpected. Thereare severalreasonsthatthiscan
happen.
Whena repairstationperforms repairs or aninspection, it
must issue a maintenance release that certifies that the aircraft is
airworthy before it can be flown. This release applies to the entire
aircraft,notonlytheworkthatwasjustperformed.Ifother
problems are found, the repair stationmust correctthem before
releasing the aircraft to service.
As a pilot, you are exposed to several potential problemsif
you encounter improper maintenance. First, you could endanger
thelivesofyourselvesandyourpassengers.Second,asthe
aircraftoperator,youareresponsiblefortheairworthinessof
yourballoon.Ifyouflyanunairworthyballoonandthatfact
comestotheattentionoftheFAA,youcouldencounter legal
problems.Third,youareexposedtotheadditionalcostof
correctingthe improper repairs.

ImproperRepairs
The repair stationmaydiscover previousrepairs that were
improperlyperformed. This canbe the result ofworkmanship,
ignorance,or differinginterpretations ofa manufacturer’sser-
vice manuals. Later in this article, I will provide some examples.

Deterioration
Itisalsopossibleforaircraftpartstodeteriorate between
annual inspections. Storage conditions, such as heat and humid-
ity,cancausesomepartstobecomeunserviceable.Ifapart
deteriorates beyond service limits, it must be replaced before the
aircraft is airworthy.

Wear orDamage
If parts of the balloon have suffered wear or damage beyond
serviceable limits since the last repair or inspection, the worn or
damaged parts must be repaired or replaced before the system is
releasedto service.

Difference ofOpinion
One of our local pilotshad landed ina field of star thistles.
The manufacturer requires patchesfor holes or tears larger than
the diameter of a pencil. The repair stationinstalled 20 stick-on
patchestocoverthe pinpricksizedholesnearthethroat.The
balloonhadpassedannualinspectionsattwootherrepair sta-
tions, so this may have resulted from a differing interpretation of
the manufacturer’s limits.

Another pilot brought a system in with a small burn holenear
the throat. The hole itself was within service limits. When we
inspected the envelope, we found that the fabric around the hole
was crisp, and would crack and fail with additional handling. We
recommended a partial panel replacement to prevent future
problems.

Examples:
Improper Repairs
We performed an annual inspection on an envelope that had
sufferedthroat burns. One gore tape was burned near the throat,
and the load rope stitching was damaged. The Kevlar cable outer
covering waspartiallymelted. The damage was repairedusing
approvedparts, butthe following repairs were improperlyper-
formed.
Kevlar Cable
Ifthepolyesterprotectivecoatingthatcoverstheinner
Kevlar fibers isdamaged, the cable mustbe inspectedfor addi-
tionaldamage. The damagedcoatingmustberemovedsothe
yellow Kevlar fiber is exposed. If the Kevlar is still yellow (its
originalcolor),heatshrinktubingmustbeappliedoverthe
exposedKevlar to protect itfromdirt, abrasion,andultraviolet
light. If the Kevlar has turned brown or black, the cable must be
replaced.
Thecablehadheatshrinktubingapplied,buttherewere
lumps of meltedcoatingvisible through the tubing. The melted
coating must be removed because it forms sharp crystals that can
eventually cut through the Kevlar. We removed theshrink tubing
andthe meltedcoating, inspected theKevlar, andappliednew
shrink tubing.
StructuralRepairs
One envelope suffered burns of parts of two fabric panels in
the throat, and melting of load rope stitching and part of one gore
tape. Partsof twofabric panelswere replacedalong the bottom
girdle, a short section of gore tap and reattached the affected load
cords and gore tapes to the new girdle was installed, and the load
rope was stitched to the bottom girdle (horizontal load tape). The
logbook entrydetailed the repairs, and included a signed main-
tenance release.
Unfortunatelythe repairswere notadequatetorestore the
integrity of the balloon’s structural framework. The replacement
gore tape was stitched to the original tape using only 1/2 inch of
overlap. The manufacturer specifies a 6 inchoverlap to provide
asmuchstrengthastheoriginaltape.Thegoretapesmustbe
connected to the bottom girdle with a bar tack (very tight zigzag
stitch). Two gore tapeswere not properly reattached.
The load rope must be attached to the bottom girdle using a

Balloon Life,April2000

bar tack. It was stitched using straight stitches. The process of
removing the melted bar tack had cut through more than half of
the bottom girdle webbing. The cut bottom girdle webbing (50%
missing)exceeded the manufacturer’sdamage limit of 10%. We
replaced a section of the bottom girdle load tape,
Fuel System
One pilot brought ina system with a complaintthatsome of
the propane cylinder service valves were difficult to turn off.
When we removedthe valve handles,wefoundbrassshavings on
the valve stems, and vise grip marks on one valve stem. Failure
of the valve stem threadscouldleave the valve open withno way
to turn it off.
We replaced the damaged service valves with new valves.

Protect Yourself
If you understand what you should look for, you have a good
chance of avoiding improper repairs.

Look at the repairs. Doesthe repaired area look like the rest
of the balloon? If anything looks unusual or out of place, ask
questions. Was thework performed using procedures in the
repair manual? Were the specified materials used?
Has the repairman or inspector attended any manufacturer’s
factory training class?
If the repair station does not provide satisfactory answers,
call the balloon’s manufacturer to double-check the repairs.
Most repair stations will not deliberately release substan-
dard work. Sometimes people will make mistakes, or they may
notunderstand the detailsof a particular manufacturer’ssystem.
The manufacturer’s factory repair training course can provide
significant additional information that may not be clearly stated
in the repair manual.
You have the final authority regarding the airworthiness of
your balloon. Be sure you understand your system well enough
torecognize the difference between proper and improper repairs.