BAE SYSTEMS (Operations) Limited,
Prestwick
International Airport,
Ayrshire,
KA9 2RW,
Scotland.
INSPECTION SERVICE BULLETIN
BAe 146 SERIES/AVRO 146‑RJ SERIES
AIRCRAFT
MANDATORY
ISB.21-150
CAA
002-03-2001
Date:
20-Mar-2001
Revision:
1
29-Jan-2002
Revision: 2 24-Oct-2002
TITLE : AIR
CONDITIONING ‑ TO INSPECT ENGINE OIL SEALS, APU AND ECS
JET PUMP
AND AIR CONDITIONING PACK FOR SIGNS OF OIL CONTAMINATION.
1.
PLANNING INFORMATION
A.
Effectivity
(1)
Aircraft affected by this inspection are defined below:
All BAe
146 100, 200, 300 Series
B.
Reason
Incidents
have been reported involving impaired performance of the flight crew.
Investigations have been conducted to determine whether the events could have
been caused by inhalation of an agent(s) resulting from oil and/or oil breakdown
products Leaking from the engine(s) or APU and contaminating the environmental
control system. At this time, there is no substantiated evidence indicating that
oil breakdown products can impair crew performance.
In the
past, oil Leaks and cabin/fLight deck odours and fumes may have come to be
regarded as a nuisance rather than a potential flight safety
issue
However
whilst investigations are being carried out to determine the nature of any
agents that may be released into the cabin environment and to define any
necessary corrective actions, oil Leaks and cabin/flight deck odours must be
regarded as a potential threat to flight safety, they should not be dismissed as
a mere nuisance and should be addressed as soon as
possible.
This
inspection bulletin has been revised to include inspection of the APU and APU
bay for signs of contamination, to include details of an APU bay cleaning
procedure and to include advice regarding identification of relevant air bleed
sources.
C.
Description
(1)
Inspection of the inside of each air conditioning pack (Pack No.1 and
Pack No.2) regenerative air ducts and air cycle machine for the presence of oil
contamination.
(2)
Inspection of an engine for signs of wet oil
contamination.
(3)
Inspection of the APU and APU bay for signs of
contamination.
NOTE: Wet oil in the engine
or APU is defined as surface coverage which can be transferred to a metallic or
plastic object. Staining, discolouration or grease/grime is not considered to be
evidence of wet oil contamination.
NOTE: Unacceptable wet
contamination of the APU bay is defined as surface coverage which can be
transferred to a metallic or plastic object.
NOTE: Unacceptable soot
contamination of the APU bay is defined as contamination which hinders the
performance of normal maintenance activities associated with the APU for example
the identification of electrical harnesses and plug idents, reading the APU hour
meter Honeywell models only) and inability to locate the source of the
contamination.
NOTE: Staining,
discolouration or grease / grime is a normal level of APU bay contamination and
is considered acceptable.
D.
Compliance
The
actions generated by this Inspection Service Bulletin are classified as
MANDATORY by the U.K. C.A.A.
(1)
Effective immediately whenever a cabin air quality problem is identified
which is suspected of being associated with oil contamination of the air supply
from the ECS packs, whether intermittent or persistent, inspect and rectify in
accordance with para 2 of this Inspection Service Bulletin, using the flowmap
logic Drawing 1. Inspection in para 2.B must be carried out even if no oil
contamination is found during para 2.A inspection.
(2)
Effective from 3rd April 2001, at the next and every subsequent A Check
or within a maximum of 500 flights and repeated at a maximum 500 flight
intervals, inspect and perform any rectification and cleaning in accordance with
para 2 of this Inspection Service Bulletin, using the flowmap logic Drawing
1.
E.
Approval
The
technical information contained in this document has been approved under the
authority of JAA Design Organization Approval
No.CAA.JA.02034.
F.
Manpower
(1) To
inspect as defined in para 2.A ‑ 2 man‑hours.
Cost and
Availability is by arrangement between the Operator and BAE
SYSTEMS.
H.
Tooling ‑ Cost and Availability
Cost and
Availability is by arrangement between the Operator and BAE
SYSTEMS.
I.
Weight and balance
Not
affected.
J.
References
Aircraft
Maintenance ManuaL
AMM
21‑50‑11 , AMM 21‑50‑17
AMM 21‑50‑47
AMM 21‑50‑51
AMM
72‑00‑00.
Component
Maintenance Manual
CMM
21‑50‑20 , CMM 21‑50‑30
CMM 21‑50‑35
CMM 49‑20‑00
All
Operator Message
AOM
00/030V.
K.
Publications affected
Not
affected.
L.
Electrical Load data
Not
affected.
2.
ACCOMPLISHMENT INSTRUCTIONS
WARNING: HYDRAULICS: PRIOR TO
ENERGISING OR DE‑ENERGIZING AIRCRAFT ELECTRICAL BUSBARS:
MAKE
CERTAIN:
‑ GROUND SAFETIES ARE IN
POSITION.
‑ ALL PERSONNEL ARE CLEAR
OF HYDRAULICALLY ACTUATED SURFACES.
‑ CONTROL LEVERS MATCH
THEIR RELEVANT COMPONENT POSITIONS.
‑ TRAVEL RANGE OF
HYDRAULICALLY ACTUATED SURFACES IS UNOBSTRUCTED.
‑ Observe all WARNINGS
and CAUTIONS appearing in the Aircraft Maintenance Manual (AMM) referred to in
this Inspection Service Bulletin.
The
inspection and cleaning procedures outlined in this ISB address problems caused
by oil contamination of the air supply from the ECS packs. It is imperative that
the source of oil is identified. The accomplishment instructions should be
carried out in accordance with the Flowmap Drawing 1, to prevent
re‑contamination. The accomplishment instructions define what must be done and
the flowmap provides the logic of when to do them.
If a
report of poor cabin air quality which is associated with oil contamination of
the air supply from the ECS packs is made at an airfield where the inspections
described in this section cannot be accomplished, it is permissible at the
discretion of the flight crew with due consideration to the nature of the event
to continue operation for the rest of the day, in order to get the aircraft to a
suitable airfield where these inspections and rectification actions can be
conducted.
NOTE: Flight crews should be
reminded of the importance of donning oxygen masks if poor cabin air quality is
suspected, and reminded of the importance of reporting smoke or smells as a
technical defect (Ref. AOM 00/030V).
B.Inspection
of both air conditioning packs (Pack No.1 and Pack No.2) regenerative air ducts
for the presence of oil contamination.
(1)
Disconnect the air conditioning pack regenerative air duct at the point
it enters the reheater/condenser ("swan neck" refer to Aircraft Maintenance
Manual AMM 21‑50‑17 Fig 201 Item 22 and AMM 21‑50‑17, page block 201 ) and
remove jet pump (refer to Aircraft Maintenance Manual AMM 21‑50‑47, page block
201
(2)
Perform
a visual inspection of the inside of both the condenser regenerative air ducts,
air cycle machine turbine
(ACM) outlet and the jet pump ducts on each air conditioning pack for
presence of oil contamination.
NOTE: It is important to
distinguish between normal levels of contamination on the inside of the ducting
and oil contamination. Dark, uniform coating on the inside surface of the
ducting is acceptable. Oil contamination in a liquid or paste form is
unacceptable.
(3) If no
oil contamination is identified in para 2.B(2) during an 'A' check or 500 flight
repeat inspection reinstall the jet pump in accordance with AMM
21‑50‑47
NOTE:
Inspection 2.C MUST be conducted:
(a) Following any reported
cabin air quality problems associated with oil contamination of the air supply
(whether or not contamination has been identified in para
2.B(2)).
(b) If oil contamination
has been identified in 2.B(2) during an inspection.
C.
Inspection of Engines and APU.
Identifying
the Relevant Bleed Source
In all
instances both the APU and engine bleed air supplies should be checked for
evidence of contamination. The APU can contaminate both ECS packs, BUT Engines 1
and 2 can only contaminate ECS Pack 1, and Engines 3 and 4 can only contaminate
ECS Pack 2. Therefore where odour reports are identified during operation of a
specific ECS pack the associated engine airs should be considered the "relevant"
engine bleeds. For example, if an odour is associated with ECS pack 1 then the
bleed systems associated with engines 1 and 2 are
relevant.
Engine
Sources
Oil
contamination of the engine bleed air supply owing to:
Engine
oil gallery diffuser pipe failure.
Engine
shaft seat leakage ‑ No.1 bearing seat.
Engine
shaft seat Leakage ‑ No.2 bearing seat.
Engine
shaft seat Leakage ‑ No.9 bearing seat.
For
pages 7 through 18 see hard copy of British Aerospace CAA MANDATORY SERVICE
BULLETIN ISB.21-150 at Revision 2 dated Oct. 24/02.