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Aviation Mechanics Bulletin May-June 1994

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Aviation Mechanics Bulletin May-June 1994 Powered By Docstoc
					        Maintenance Records —
        What Is Legal May Not
         Appear to Be Logical
                             Robert A. Feeler
                           Editorial Coordinator




Commercial and/or air carrier op-          The owner or operator is ultimately
erations governed by U.S. Federal          responsible for maintenance and
Aviation Regulations (FARs) Parts          maintenance records, as stated in
121, 125, 127, 129 or 135 are re-          Parts 91.405 and 91.417. In prac-
quired to define their maintenance         tice, however, the technician usually
record-keeping policies and proce-         must interpret the regulations and
dures in their manuals, which are          maintain records that comply with
approved by the U.S. Federal Avia-         the FARs.
tion Administration (FAA). Techni-
cians employed by such operators           Although the technician must meet
must be familiar with their employ-        the legal requirements, a record-
ers’ policies and procedures, and          keeping format that merely sticks to
ensure that all maintenance-record         the letter of the FARs may not be the
entries are in accord with the manual.     format that appears most logical.
For the general aviation technician        Also, recent changes in FAA poli-
operating under Part 91, however,          cies and interpretations, and possible
the subject is more complex.               f u t u r e c h a n g e s i n t h e FA R s
FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994              1
governing aircraft maintenance            for ensuring that requiredinspection,
records, further challenge the gen-       servicing, overhaul and retirement
eral aviation technician’s record-        functions are accomplished as in-
keeping tasks.                            tended by the manufacturer and/or
                                          the regulatory agency. These pro-
    Maintenance Records                   grams must, however, be supported
                                          by a paper system that records:
FAA Advisory Circular (AC) 43-9B,
Maintenance Records, was last re-         •    A description of the work per-
vised in January 1984. Although the            formed (or reference to data
regulatory references to Part 91 do            a c c e p t a b l e t o t h e [ FA A ]
not reflect the later recodification of        Administrator);
Part 91, the AC’s content remains
applicable today. Paragraph 6(c) in-      •    The date of completion of the
cludes this statement: “Maintenance            work performed; and,
records may be kept in any format
which provides record continuity,         •    The signature and certificate
includes required contents, lends it-          number of the technician ap-
self to the addition of new entries,           proving the aircraft for return to
provides for signature entry, and is           service.
not confusing.”
                                                Powerplant and
This allows for a broad variety of            Component Records
record-keeping systems, from the
simple log books provided with the        FAR Part 91.417(a)(1) requires ap-
aircraft to sophisticated paperwork       propriate records for “... each air-
systems available from several ven-       craft (including the airframe) and
dors. It is important to note that many   each engine, propeller, rotor, and ap-
of the computer-generated mainte-         pliance of an aircraft.” This is an-
nance planning and scheduling soft-       other broad regulation. A single log
ware applications do not meet the         book with entries appropriate to each
requirements for FAA-required main-       component would constitute a legal
tenance records. Merely tracking the      record; however, in all but the sim-
time and date when required main-         plest aircraft, this would not be a
tenance actions are performed is not      logical record-keeping practice.
an acceptable maintenance record.
                                          When powerplants and components
Software applications that track and      are removed for overhaul or repair,
schedule maintenance are excellent        it is more logical to have a separate

2            FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
record of the maintenance. With            hours or cycles ofoperation. Airframe
some components being unit-                structural components such as land-
exchanged, it is also prudent to have      ing gear parts, helicopter rotor parts
a separate record that can be trans-       or critical flight control parts may also
ferred with the component. Here            have life limits.
again, the format of these compo-
nent records can vary from a simple        Powerplant life-limited parts are usu-
log book to a single paper card.           ally specified in a service bulletin
                                           issued by the engine manufacturer.
The form and content of component          Airframe life-limited parts are often
records is increasingly important as       listed in the inspection limits sec-
components become more complex             tion of the manufacturer’s mainte-
and costly. The modification status        nance manual. Such parts may also
of a component is of critical impor-       be listed in the aircraft type certifi-
tance when the component is trans-         cate (TC) data sheets. This is some-
ferred. Modifications often affect the     times a direct listing of individual
fit and function of a component, and       parts but is more often a separate
if the modification status is uncer-       document or engineering report ref-
tain or unknown, a costly compo-           erenced in the TC data sheet.
nent can become an addition to the
waste can.                                 In the past, some FAA offices have
                                           demanded that operators be able to
The FARs do not specifically ad-           trace each life-limited part “back to
dress the modification-status aspect       its birth certificate,” with detailed
of component record keeping, but           records of each installation, operating
logic dictates that the astute techni-     hours and cycles, and removal. For
cian keep such records for compo-          parts such as engine discs, this posed
nents under his responsibility and         a tremendous burden and, in some in-
that he demand such records when           stances, resulted in costly replacement
acquiring a replacement component.         of parts for which the operator could
                                           not produce the parts’ history under
     Life-limited Parts                    the aircraft’s previous owner. Accord-
                                           ing to FAA officials, that policy is no
Part 91.417(2)(ii) requires that the       longer in effect and “current status” is
records contain “... the current status    defined as an acceptable record of pre-
of life-limited parts of each airframe,    vious usage from an operator with an
engine, propeller, rotor, and appli-       approved record-keeping system. Nev-
ance.” Every turbine engine has parts      ertheless, life-limited parts records
for which the manufacturer has estab-      coming from a foreign operator, or
lished a maximum life limit, stated in     from an operator with aquestionable
FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994             3
system of records, might still be sub-    •    The next recurring action due
jected to a back-to-its-birth-                 (if applicable).
certificate search.
                                          Formerly, many FAA offices re-
                                          quired that the only acceptable
    Airworthiness Directive               record be the “dirty fingerprinted
     Compliance Records                   work card” of the AD compliance.
                                          That interpretation, according to the
Airworthiness directive (AD) com-         FAA, is no longer valid; however,
pliance records have probably gen-        the critical test of AD compliance
erated more controversy during the        records is still the “method of com-
past 10 years than any other facet of     pliance.” Merely stating “AD xx-
aircraft maintenance records. Part        xx-x complied with” is not
91.417(2)(v) requires that the records    considered sufficient. The record
contain “The current status of appli-     must include sufficient details of how
cable airworthiness directives (AD)       compliance with the AD was accom-
including, for each, the method of        plished. For example, “Inspected
compliance, the AD number, and re-        xxxx component in accordance with
vision date. If the AD involves re-       paragraph 3 of Manufacturer’s Ser-
curring action, the time and date         vice Bulletin xx-xx, revision A. No
when the next action is required.”        defects found,” would satisfy the
                                          method of compliance.
Computer-generated records that list
only compliance with ADs provide          The Airworthiness Directive Com-
a convenient record of AD status,         pliance Record (Figure 1, Page 5)
but the records are incomplete with-      taken from AC 43-9B, Appendix 1
out the following:                        is an FAA-suggested format. This
                                          format may meet the legal require-
•     The date and aircraft hours/        ments, but many technicians would
      cycles at time of compliance;       question it as being a logical record
                                          format with the limited space avail-
•     The AD number and revision          able to enter method of compliance.
      date;
                                          Although some consider the prac-
•     The method of compliance;           tice “overkill,” many operators have
                                          adopted as an AD compliance record
•     The signature and certificate       system a set of manila file folders,
      number of the technician per-       one per AD number. Each folder
      forming the work; and,              contains:


4            FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
                                                                                                                      Airworthiness Directive Compliance Record
                                                                                 * Aircraft, Engine, Propeller, Rotor, or Appliance: Make _____________ Model __________ Ser. No. _____________

                                                                            AD                                                                                                          Authorized
                                                                          Number                                                      Airframe     Component                             Signature,
                                                                             &                    Compliance    Method     Date      Total Time    Total Time                Next Comp. Certificate
                                                                         Amendment Date            Due Date       of        of      In Service at In Service at               Due Date    Type &
                                                                          Number Received Subject Hours/Other Compliance Compliance Compliance Compliance One-time Recurring Hours/Other Number     Remarks




FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
                                                                         * Suggest providing a page for each category

                                                                          Figure 1. Airworthiness Directive Compliance Record.




5
•   A copy of the AD;                    batch, etc.). Such entries should also
                                         be supported by the signature and
•   A copy of the manufacturer’s         certificate number of the technician
    service bulletin, if applicable;     who researched the applicability.

•   A photocopy of the work card,             Records Retention
    log page, etc. detailing method
    of compliance and sign-off; and,     How long must each record be kept?
                                         For an air carrier or commercial op-
•   A reference to the log page, in-     erator, records retention policies
    spection visit or work order on      must be defined in their approved
    which the AD was accomplished.       policies and procedures manuals. For
                                         the general aviation operator gov-
For repetitive ADs, the record of the    erned only by Part 91.417(b), Table
latest repetition is merely dropped      1 (page 7) summarizes the records-
into the folder. This simple but ef-     retention legal requirements, as well
fective practice provides easy refer-    as the common industry-practice
ence and irrefutable confirmation to     logical requirements. In deciding
support a computer listing of AD         how long to keep records, the test
status. For large fleet operators or     might be what a buyer of the aircraft
others concerned with the bulkiness      would want to see, and the operator
of accumulated records, microfilm-       should retain the records
ing these records is the answer.         accordingly.

Another issue in AD compliance            New Uses for FAA Form
records is applicability. Although
Part 91.417(2)(v) only requires          FAA Form 8130-3, Airworthiness
records of applicable ADs, what          Approval Tag, is used to certify Ex-
about those that might apply? Ap-        port Airworthiness Approval of Class
pliance ADs, such as those pertain-      II or Class III products.
ing to seat belts or avionics units,
could apply to almost any aircraft.      A Class II product is defined as a
Legally, the record keeper need not      major component of an aircraft, air-
maintain records of those not            craft engine or propeller, the failure
applicable. Logically, it is prudent     of which would jeopardize the safety
to record all such ADs in the AD         of the aircraft, engine or propeller.
status records and make an entry cer-
tifying that the AD does not apply       A Class III product is any part or com-
(because the part is not installed,      ponent that is not a Class I (aircraft,
not in the affected serial-numbered      engine or propeller) or Class II
6           FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
                            Table 1
            Record Retention Requirements under
    U.S. Federal Aviation Regulations (FARs) Part 91.417(b)

       Type of Record              Legal Retention         Logical Retention

       Routine servicing            Until repeated               30 days

   Scheduled inspections/         Until repeated or            3 to 5 years
    routine maintenance          superseded/1 year*

  Nonroutine maintenance/               1 year                 3 to 5 years
   pilot reported defects

          Altimeter and            2 years/repeated         2 years/repeated
       transponder tests

       Modifications &                Permanent                Permanent
       alterations/337s

       Life-limited parts           Until scrapped             Permanent

   Airworthiness Directives           Permanent                Permanent

    Total time in service of          Permanent                Permanent
   airframe, engines, rotors
          & propellers

  Time since overhaul of all          Permanent                Permanent
     components having
  specified overhaul period

  Current inspection status            Current                1-year history
  and time since inspection

        List of open or             Until repaired            Until repaired
       deferred defects


  * Part 91.417(b)(1) states, “The records specified in paragraph (a)(1) of
  this section shall be retained until the work is repeated or superseded by
  other work or for 1 year after the work is performed,” which the Federal
  Aviation Administration interprets to mean whichever comes first.




FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994         7
product. Class III parts are generally a   Part 135, having a continuous air-
detail part or minor assembly whose        worthiness maintenance program, or
failure would not jeopardize safety.       by a certificated repair station. This
                                           new use means that technicians
Class III parts can include common         might receive parts with a Form
hardware.                                  8130-3 tag certifying it as an air-
                                           worthy part in lieu of the more com-
In late 1993, the FAA added another        monly used repair station “yellow
section to Form 8130-3, allowing its       tags.”
use for additional purposes. These
uses are:                                  Details of the work performed should
                                           be entered in the space provided or
•   Conformity Certification — The         attached to the tag with a cross-
    form may now be used to record         reference entered in the space. Tech-
    conformity to specifications of a      nicians may wish to review FAA
    new product only. This certifies       Order 8130.21A, dated January 3,
    that the part has been inspected       1994, for more details on the use of
    and found to meet specifications       this revised form.
    under which the part was
    manufactured.                          A sample of the revised Form8130-3
                                           completed for use as a Return-to-
•   Identification — The form may          Service Approval is shown in Figure
    now be used to identify a new          2 (page 9).
    product to ensure part traceabil-
    ity and accountability. This is        New Rule in the Making
    authorized for use only by the
    manufacturer, to identify the          An Aviation Rulemaking Advisory
    part and follow it in shipment.        Committee (ARAC) with partici-
                                           pants from the industry, including
•   Return-to-Service Approval —           individual technicians, has been
    The form may now be used to            working for the past three years on
    certify approval for return to ser-    draft proposals to revise current
    vice on Class II and Class III         FARs pertaining to maintenance
    products after maintenance or          records. The primary goal of this
    alteration. This is a major            committee has been to consolidate
    change in the use of this form.        all FARs affecting maintenance
                                           records into one section of the rules,
The Return-to-Service Approval can         primarily Part 91. If this is accom-
only be issued after work by a             plished, all record-keeping and re-
certificate holder under Part 121 or       tention requirements could be
8            FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
                                                                                                               Graphic not available




FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
                                                                         Figure 2. U.S. Federal Aviation Administration Form 8130-3, Airworthiness Approval
                                                                         Tag, used as a Return-to-Service Approval.




9
uniform. Operators and technicians             status must be specified and
would not need to be concerned with            updated. The modification status
changing record requirements when              may be accomplished, but not
an aircraft is transferred from one            necessarily be required to be
operation to another.                          stated, by means of a service
                                               bulletin listing;
Specific issues expected to be ad-
dressed by this proposed rule-making      •    Clarifying the methods of docu-
include:                                       menting life cycle-limited items
                                               and records thereof; and,
•    Manufacturer’s certification of
     new parts — Providing a means        •    Providing for electronic
     of identifying each new part and          record-keeping in lieu of hand-
     specifying the modification/              written or printed maintenance
     configuration status of the unit;         records.

•    Further defining and clarifying      Electronic record keeping is a major
     content and disposition of           part of this anticipated rule-making
     records and of records-retention     proposal. The ARAC members want
     requirements;                        the FARs amended to recognize to-
                                          tal electronic record-keeping systems
•    Further defining and clarifying      and “electronic signatures,” with
     transfer-of-records requirements;    suitable security, safeguards and
                                          backups to ensure the integrity and
•    Further defining and clarifying      accuracy of the records. The tech-
     repair station record-keeping        nology is readily available, and the
     requirements;                        regulations need only be revised to
                                          allow it to replace pen and paper.
•    Further defining and clarifying
     modification requirements,           According to the FAA, the initial
     particularly as they pertain to      Notice of Proposed Rule Making
     components. The rule is expected     (NPRM) is targeted for release this
     to recognize that modification       year.♦




10           FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
                             NEWS & TIPS

   Alternative to Halon                    electronic equipment. As of this date,
                                           this Halon alternative has not been
    Fire-extinguishing                     proposed as a replacement for aircraft
    Agent Developed                        engine fire-extinguishing installations,
                                           and these systems must continue in
The ozone-depleting effects of Halon       operation, using the Halon agent from
resulted in its complete production        the “bank” established by industry,
phase-out on Dec. 31, 1993. With           which recycles the agent from exist-
Halon having been the fire-                ing installations.
extinguishing agent of choice for so
many aviation installations, the in-        National Safety Council
dustry has been concerned about
what type of agent might best re-
                                             Issues Reminder on
place it. Ansul Fire Protection Co.            Pushback Safety
recently announced that it has re-
ceived a formal Underwriters Labo-         The International Air Transport Sec-
ratories Listing (UL EX-4510) for          tion of the National Safety Council
INERGEN fire extinguishing agent.          recently held a ground safety semi-
Known as “the environment-friendly         nar in San Francisco. Speakers called
Halon alternative,” INERGEN is said        for procedural changes to aircraft
to extinguish fire while continuing        pushback operations to reduce the
to support human life.                     risks to personnel posed by aircraft
                                           nosewheels or tug vehicles.
INERGEN has also been accepted,
without restriction, by the U.S.           Although relatively few incidents have
Environmental Protection Agency            been reported, the severity of the inju-
(EPA). This includes acceptance for        ries that resulted from pushback acci-
normally occupied areas and                dents was found to be very high.
unoccupied areas, and as an inerting
agent for explosion-suppression            Many of the 40-plus accidents re-
applications.                              corded in the past 30 years have re-
                                           sulted in fatalities or amputations of
INERGEN is a mixture of three inert        limbs.
gases: nitrogen, argon and carbon di-
oxide. As a “clean” gaseous extin-         The Air Transport Association of
guishing agent, it is intended to be       America (ATA), in speaking for the
suitable for the protection of sensitive   U.S. airline industry, reported that
FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994           11
injuries could be prevented by not        operators have adopted the recom-
allowing the headset operator to walk     mendation to have the communica-
alongside during the pushback pro-        tions activity conducted from the
cedure. An increasing number of           comparative safety of the tug.♦




                  MAINTENANCE ALERTS

This information is intended to pro-      any accident investigation data. Air
vide an awareness of safety problems      traffic control data, information de-
so that they may be prevented in the      rived from survivor interviews and
future. Maintenance alerts are based      examination of the wreckage enabled
upon preliminary information from gov-    the investigators to reconstruct the cir-
ernment agencies, aviation organiza-      cumstances leading to the crash.
tions, press information and other
sources. The information may not be       The aircraft had passed through the
entirely accurate.                        localizer at such an angle as to pro-
                                          duce a full-scale deflection on the
   Inadequate Bonding                     cockpit indicator. Several more
                                          course corrections were evident as
  Suspected as Cause of                   the airplane bracketed the localizer.
 Fatal Commuter Crash                     After intercepting the localizer, the
                                          airplane remained above the
In January 1992, a Beechcraft             glideslope for about five nautical
1900C, operated by a U.S. commuter        miles (nm) (9 kilometers). About
airline, descended into a wooded          eight nm (14 kilometers) from the
hillside while conducting an instru-      runway threshold, the descent steep-
ment landing system (ILS) approach        ened, and the airplane passed rap-
in upstate New York, U.S. The first       idly through the glideslope into the
officer and one passenger were fa-        area that should have produced a
tally injured. The captain and one        full-scale “fly-up” indication in the
passenger survived.                       cockpit. The rate of descent reached
                                          2,000 feet (610 meters) per minute.
The aircraft was not equipped with a
flight data recorder and thecockpit       The airplane passed the final ap-
voice recorder was so damaged in the      proach fix 600 feet (183 meters) be-
ensuing fire that it could not provide    low the published minimum, at
12           FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
which time radar data from the con-         Normally, as an airplane passes
trol center were lost. The impact of        through such conditions, an electri-
the airplane 3.9 nm (7.2 kilometers)        cal charge builds up on surfaces im-
from the runway threshold and 626           pinging the air, but the charge is
feet (190 meters) below the                 conducted through the airplane struc-
glideslope indicated that the descent       ture to static discharge wicks on the
had continued until impact.                 trailing edges of wing and empen-
                                            nage surfaces and passes harmlessly
During the interview immediately            into the air. If, however, there is no
after the accident, the captain could       conductive path to the airplane struc-
recall no mechanical problems and           ture (the electrical ground), the
stated his belief that the airplane was     charge can build on electrically iso-
“... on the glideslope with the             lated surfaces until it develops a po-
localizer and glideslope needles            tential for arcing from an isolated
nearly centered throughout the de-          surface to another part of the
scent.” Examination of the cockpit          airplane.
instruments in a laboratory revealed
witness marks of the needles near           P-static may be evident to pilots as
the on-glideslope position, and other       static heard on radio receivers, but it
flight instruments provided altitude        can also interfere with navigational
and course indications that were con-       radio reception and the display of
sistent with the intended approach          glideslope or localizer information
path.                                       in the cockpit, as demonstrated by
                                            tests conducted by the NTSB after
The U.S. National Transportation            the accident.
Safety Board (NTSB), in assessing
the probable cause of the accident,         The NTSB found evidence of an in-
did not exclude the possibility that        adequate electrical ground path be-
the glideslope indication observed          tween the radome and the fuselage
by the captain was unreliable as a          on five of the eight other Beechcraft
result of precipitation static (P-static)   1900C airplanes in this operator’s
interference. P-static interference is      fleet. It was noted that pinhole-size
caused by an electrostatic charge           burn marks created during P-static
built up on an airplane as it passes        testing appeared to be identical to
through particulate matter suspended        those observed (before the tests) on
in the air. The particulate matter usu-     the radomes of several aircraft in
ally is in the form of rain, snow or        this fleet. Tests indicated that suffi-
ice. The weather conditions during          cient electrical charge could have
the descent were conducive to fog           built, in the weather conditions at
or freezing fog.                            the time of the accident, to produce
FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994           13
an electrostatic discharge that is typi-   provisions should be closely inves-
cal of P-static interference.              tigated by technicians responding to
                                           reports of radio static.
The radome of the accident airplane
was so damaged that only two of the            Contaminated Fuel
12 radome mounting screw holes
could be examined. While those
                                                Downs Airplane,
holes showed possible evidence of                  Killing 16
an inadequate ground path from the
radome to the fuselage, the evidence       In early 1992, a de Havilland
was not conclusive. Postaccident           DHC-6-200 operating in the west-
tests did show that arcing between         ern U.S. crashed shortly after take-
the radome and the fuselage could          off, resulting in fatal injuries to both
affect the glideslope signal, causing      pilots and 14 of the 20 parachutists
deviation of the needle toward a cen-      on board.
tered "on-glideslope" indication and
other unreliable cockpit instrument        The investigation disclosed that one
indications.                               of the airplane’s fuel tanks had been
                                           serviced with contaminated fuel,
As a result of these findings the          causing the right engine to lose
NTSB has issued a safety recom-            power shortly after liftoff. In addi-
mendation to the U.S. Federal Avia-        tion to this primary cause, it was
tion Administration (FAA) calling          determined that the pilot feathered
for the issuance of an airworthiness       the propeller on the left engine, and
directive applicable to Beechcraft         that the airplane had been loaded in
1900C airplanes to require regular         excess of the maximum gross weight
inspections or modifications to en-        and beyond the forward center of
sure the proper electrical grounding       gravity limit.
of the conductive nose radome coat-
ing to the metal airframe.                 It was confirmed that the fuel in the
                                           airport storage tanks had become
While technicians maintaining and          contaminated with water. The op-
inspecting the Beechcraft 1900C            erator did not have an adequate qual-
should be particularly alert when          ity control procedure, thus allowing
checking bonding and grounding             this condition to go undetected.
connections, the situation is not
necessarily peculiar to this type of       This is a classic example of an acci-
aircraft. P-static interference on ra-     dent chain of events where just one
dios can be much more than just a          action could have broken the chain
nuisance, and electrical grounding         and prevented the accident:
14           FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
•   Checking for water in storage          cracks originating from relief
    tanks;                                 notches at the base of the clevis ears.
                                           They also found an extensive oxida-
•   Taking a sample from the               tion layer between the sections mak-
    refueler before fueling the            ing up the aft clevis ear. Although
    airplane;                              the corrosion had evidently been oc-
                                           curring for some time, the evidence
•   Performing a sump check after          indicated that the fatigue cracks at
    refueling; or,                         the base of the clevis ears caused the
                                           failure. Similar fatigue cracks were
•   Conducting a thorough preflight.       found in the left-wing fittings of the
                                           accident aircraft.
Fuel quality control procedures are
monotonous and rarely disclose a           Safety concerns related to cracking
problem, but this accident shows the       and corroding of these clevis ears
cost of ignoring these basic safety        were first raised after a September
procedures.                                1991 crash of a similar airplane. Fol-
                                           lowing its investigation, the NTSB
    Fatigue Crack Cited                    recommended (Safety Recommen-
                                           dation A92-36) that the U.S. Federal
        As Cause of                        Aviation Administration (FAA) is-
     Second PA-25-150                      sue an airworthiness directive (AD)
       Wing Failure                        requiring immediate inspection for
                                           corrosion and cracking of the sub-
In May 1993, a Piper PA-25-150 be-         ject clevis ears. The FAA did not
ing operated as a crop sprayer suf-        take prompt action and the NTSB
fered a failure of the right wing          considered this an “Open — Unac-
attachment, resulting in a crash fatal     ceptable Response.”
to the pilot. In its investigation, the
U.S. National Transportation Safety        Following the 1993 wing failure, the
Board (NTSB) found that the forward        FAA issued a Notice of Proposed
spar fuselage attachment assembly for      Rulemaking (NPRM) concerning re-
the right wing had separated at the        petitive inspections of this section
clevis ears. The separation was through    on the subject airplanes, but no ac-
two fittings, P/Ns 61005 and 61006,        tion has taken place. The NTSB has
that had been welded together to form      issued a second safety recommen-
the clevis ears.                           dation calling for the issuance of an
                                           emergency AD requiring expedited
Metallurgical examination of the fit-      inspections of this section on
tings by the NTSB revealed fatigue         PA-25s. Technicians inspecting and
FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994          15
maintaining these aircraft should         department. It was established that
ensure that they are familiar with        neither the manufacturer of the
this potential problem section.           battery packs nor the system’s
                                          manufacturer had provided writ-
      Emergency Lighting                  ten guidance to the airline’s main-
                                          tenance department on the
     Battery-pack Failure                 importance of replacing individual
          Blamed on                       power cells in the same sequence
     Maintenance Practices                in which they were removed, and
                                          of the correct procedure for sol-
In an accident investigation of a DC-     dering the tap wire to the battery
10-30 that skidded off the runway         packs.
on landing, the U.S. National Trans-
portation Safety Board (NTSB) dis-        Because of the decreased charge
covered that part of the cabin            level, there was sufficient power
emergency lighting system had failed      to indicate an operational system
to actuate. Subsequent analysis and       at the cockpit instrument console,
testing of the system components          but not enough to actually operate
discovered that the battery packs         the system. The tests concluded
powering the various sections of the      that, as a result of improperly sol-
floor path and general cabin emer-        dering the tap wires and improp-
gency lighting did not function as        erly replacing the individual cells,
intended.                                 the charge level was not sufficient
                                          to illuminate the overhead and
Each of the four battery packs con-       door emergency lighting system.
tained 24 individual power cells. In-
vestigation revealed that the tap wire    Technicians maintaining and ser-
or primary lead was incorrectly sol-      vicing emergency lighting systems
dered onto all four battery packs. In     should review their practices and
addition, individual battery cells        ensure that the systems are func-
were out of the original factory-         tionally tested following repair or
assembled sequence. This affected         replacement of the battery packs.
the amount of charge each battery
cell would accept during charging            Faulty Combustion
and thereby diminished the overall
level of power.
                                               Heater Causes
                                            Explosion on Aircraft
The operator’s maintenance records
showed that the battery packs had been    In August 1993, a twin-engine
serviced by the airline’s maintenance     Cessna 414A was involved in an
16           FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
incident when an explosion within          operation of the heater, even with
or below the nose baggage compart-         these defects present. It is likely that
ment blew the left and right nose          these conditions had been present
baggage doors off the airplane. For-       for some time and remained unde-
tunately, the airplane was taxiing for     tected because the heater was not
takeoff and no injuries occured.           frequently used on the ground.

The U.S. National Transportation           A review of the U.S. Federal Avia-
Safety Board (NTSB) determined             tion Administration (FAA) Service
that the explosion occurred when the       Difficulty Report files disclosed
Janitrol Model B-4050 heater, lo-          other instances of Janitrol heater
cated under the nose baggage com-          malfunctions, at least one of which
partment floor, malfunctioned and          resulted in an inflight fire and fatal
allowed fuel vapor to accumulate in        crash. Janitrol heaters Models
the nose section. Examination dis-         B-1500, B-2030, B-3040 and B-4050
closed that the combustion blower          are all similar in design, differing
motor’s commutator brushes were            only in size and output capacity.
excessively worn. As a result, there       These units are installed in a wide
was little or no combustion airflow        variety of light single- and twin-
available to the heater while the air-     engine aircraft and malfunctions
plane was on the ground.                   have been reported in various
                                           installations.
It was also discovered that the com-
bustion air-pressure switch, which         As a result of these findings, the
senses combustion air differential pres-   NTSB has recommended the issu-
sure, or airflow, was also malfunc-        ance of an airworthiness directive
tioning. The switch contacts, which        calling for an operational check and
are normally open, were found to be        adjustment, if required, of the com-
closed, and the adjusting screw had        bustion air-pressure switch as well
been turned to a setting correspond-       as an inspection of the heater-fuel
ing to an extremely low combustion-        drain-line installations.
air differential pressure.
                                           The recommendation further sug-
In normal operation, a minimum pre-        gests that:
determined amount of combustion
airflow must be sensed by the switch       •    The FAA require a redesign or
before its contacts close, allowing             modification to the subject heater
actuation of the heater’s ignition coil         systems to make them fail-safe
and fuel valve. In flight, sufficient           by preventing the flow of fuel into
ram air is available to allow normal            the heater in the absence of
FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994           17
      sufficient combustion airflow and/        warn against arbitrarily moving
      or heater ignition if the switch          the switch screw to facilitate
      malfunctions; and,                        heater operation.

•     The manufacturer issue an alert      Technicians inspecting and main-
      safety (service) bulletin explain-   taining any aircraft having a
      ing the switch function, outlin-     Janitrol combustion heater system
      ing the requirements for testing     should review the manufacturer’s
      and adjustment, emphasizing the      inspection and maintenance data
      potential fire and explosion haz-    and ensure that these critical heater
      ards from improper service or        systems are properly adjusted and
      adjustment, and specifically         maintained.♦


                          NEW PRODUCTS

     Eye and Body Wash                     bottles of eye and body wash and is
                                           designed to hold the bottles firmly
     Station Requires No                   in place, yet quickly accessible in
        Water Access                       an emergency.

The Masuen First Aid Co. has intro-        According to the manufacturer, the
duced an eye wash station designed         station is made of durable, easy-to-
for use in areas where there is no         clean plastic. Two bottles of eye and
                                           body wash are included.

                                           For more information, contact:
                                           Masuen First Aid Co., 490 Fillmore
                                           Avenue, Tonawanda, NY 14150,
                                           U.S. Telephone (716) 695-4999.
     Graphic not available
                                              New Packaging Meets
                                               OSHA Regulations
                                           The more stringent application of
                                           the U.S. Occupational Safety and
                                           Health Agency (OSHA) regulations
access to plumbing or running wa-          regarding the availability of mate-
ter. The station holds two 32-ounce        rial safety data sheets (MSDS) has

18            FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994
resulted in more violations and fines      For more information, contact: CRC
for industrial users of toxic or haz-      Industries, 885 Louis Drive,
ardous chemicals. The lack of MSDS         Warminster, PA 18974, U.S. Tele-
for each hazardous chemical was            phone (215) 674-4300.
ranked as the fourth most frequent
violation cited by OSHA, with 5,995         Balancing Unit Adapts
citations issued.
                                            To Helicopters, Engines
                                                Or Propellers
                                           TEC Aviation Division has introduced
                                           its newest balancing and tracking in-
                                           strument, ACES Ultra. TEC says that
                                           this multipurpose instrument can be
                                           used to perform helicopter rotor track
                                           and balance, turbine engine vibration
    Graphic not available                  analysis, acoustic analysis and pro-
                                           peller balancing.

                                           The unit houses six vibration chan-
                                           nels and two tach channels that are
                                           said to work with any sensor on the
                                           market. Simple menu-driven programs
                                           download from an ACES Procedure
                                           Card, making the unit a helicopter-
                                           specific or engine-specific analyzer.
CRC Industries has revised its pack-
aging and labeling standards to in-
corporate the MSDS into the product
label on its aerosol cans. CRC said
that companies using its “portable
MSDS” product line have discov-
ered that compliance with the OSHA
requirements is much easier, because           Graphic not available
the necessary data are always avail-
able at the point of use.

The patented, removable label is
available on a wide range of CRC
aviation aerosol specialty products.
FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994         19
For more information, contact:            The nozzle incorporates a built-in
ACES Systems, 10737 Lexington             pressure regulator enabling its use
Drive, Knoxville, TN 37933-0996,          with all fuel sources having inlet
U.S. Telephone (615) 966-5856.            pressures up to 125 pounds per
                                          square inch, and is said to deliver
     Special Fuel Nozzle                  the fuel at a constant rate despite
                                          fluctuations from the pump source.
     Enhances Safety in                   The maker claims that the unit auto-
      “Hot Refueling”                     matically stops fuel flow, and visu-
       Of Helicopters                     ally signals the operator, when tanks
                                          are full. Emergency disconnects are
The Adel Wiggins Group has intro-         said to be spill-free, even at maxi-
duced a new closed-circuit fuel           mum flow rate, so fire potential is
nozzle and adapter specially de-          minimized. In addition, the manu-
signed for use in refueling helicop-      facturer states that nozzles are com-
ters with the engines operating for a     patible with a variety of receivers
quick turnaround, often termed “hot       from Adel Wiggins and HR Textron.
refueling.” The nozzle, when coupled
with an approved receiver on the air-     For more information, contact: Adel
craft fuel tank, is said to provide the   Wiggins Group, 5000 Triggs Street,
safest method of conducting such          Los Angeles, CA 90022, U.S. Tele-
operations.                               phone (213) 269-9181.♦




                           Graphic not available




20           FLIGHT SAFETY FOUNDATION • AVIATION MECHANICS BULLETIN • MAY–JUNE 1994

				
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