AirComm Corporation Airbus EC120 Cabin Air Conditioner Instructions for Continued Airworthiness User Manual

							AIR CONDITIONER SERVICE MANUAL EC120-200M-1 
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CHAPTER 1 
INTRODUCTION 
1. Scope 
The  scope  of  this  manual  encompasses  scheduled  and  unscheduled  maintenance 
procedures for continued airworthiness of Air Comm Corporation air conditioning system 
installed in Airbus EC120B series helicopter. 
2. Purpose 
The purpose of this manual is to provide aircraft field mechanic necessary information to 
maintain the air conditioning system. 
3. Arrangement 
This  manual  is  arranged  by  chapters  which  are  broken  down  into  paragraphs  and  sub-
paragraphs.  All  chapters  and  paragraphs  are  listed  in  the  front  of  this  manual  in  the 
Table of Contents, and are further identified by their individual page number. 
4. Applicability 
This  manual  is  applicable  to Airbus Helicopter  model EC120B equipped  with  Air Comm 
Corporation kit number EC120-200 air conditioner system. 
5. Definitions 
The  following  terms  are  provided  to  give  a  ready  reference  to  the  meaning  of  some 
words  contained  within  this  manual.  These  definitions  may  differ  from  those  given  by  a 
standard dictionary. 
 
A. Ambient  air  temperature: Temperature  of  the  air  surrounding  a  person  or 
object. 
B. Charging  station: An  air  conditioning  system  service  unit  which  is  capable  of 
evacuating and charging an air conditioner. 
C. Cold: The absence of heat. 
D. Condensation: The process of changing a gaseous phase into a liquid. 
E. Desiccant: Material  used  in a receiver/drier  bottle,  designed  to  absorb  moisture 
from refrigerant. 
F. Evaporate: To change from a liquid into a vapor. 
G. Heat  load: The  amount  of  heat  which  the  air  conditioner is  required  to  remove 
from the aircraft cabin. 
H. Inches  of  mercury: A  measurement  of  pressure,  normally  used  for  pressures 
below atmospheric, one inch of mercury is equal to approximately one half pound 
per square inch. 
I. Pressure,  ambient: The  pressure  of  the air  surrounding  a  body,  normally 
measured in pounds per square inch, or PSIG. 
J. Refrigerant: A  fluid  which  is  used  in  an  air  conditioning  system  to  absorb  heat 
from  the  cabin  and  carry  it  outside  the  helicopter  where  it  can  be  transferred  to 
the outside air. 
K. Relative  humidity: The  ratio  of  the  amount  of  water  vapor  in  the  air  to  the 
amount of water vapor required to saturate the air at the existing temperature. 
L. Thermostat: An  air  conditioning  control  which  senses  the  temperature  of  the 
evaporator coil and causes the system to cycle or by-pass to maintain the proper  
						

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temperature of cooling air. 
M. Vacuum: A  negative  pressure,  or  pressure  below  atmospheric;  it  is  usually 
expressed in inches of mercury. 
N. Vapor: The  gas  formed  by  boiling  or  evaporating  a  liquid.    A  gas  at  a 
temperature below its critical temperature. 
6. Abbreviations 
InHg: Inches of Mercury 
Lbs: Pounds 
Oz: Ounces 
Psig: Pounds per Square Inch (gauge) 
Gr: Grams 
Kg: Kilograms 
Kg/cm: Kilograms per Centimeter 
Ml: Milliliters 
mm: Millimeters 
Nm: Newton-meters 
7. Precautions 
The following precautions are found throughout this manual, and will  vary depending on 
the seriousness of the Hazard or Condition: 
 
WARNING:  May  be  a  maintenance  procedure,  practice,  condition,  etc.,  which  could 
result in personal injury or loss of life. 
CAUTION:  May  be  a  maintenance  procedure,  practice,  condition,  etc.,  which  could 
result in damage or destruction of equipment. 
NOTE:  May  be  a  maintenance  procedure,  practice,  condition,  etc.,  or  a  statement 
which needs to be highlighted. 
8. Units of Measure 
All  measurements  contained  within  this  manual  are  given  in  United  States  standard 
measurement, followed by metric conversion in parentheses. 
9. Information Essential to Continued Airworthiness 
This manual provides information which is required for operation and maintenance of the 
Air  Comm  air  conditioning  system  installed  in the  Airbus model EC120B series 
helicopter.  After  completion  of  the  air  conditioner  installation  this  document  must  be 
placed with the appropriate existing aircraft documents. 
10. Reference Documents 
The  approval  basis  of  the  system  covered  by  this  ICA  is  Supplemental  Type  Certificate 
SR00491DE. 
11. Distribution 
This  document  is  to  be  placed  with  the  aircraft  maintenance  records  at  the  time  of 
system installation. 
 
Changes  will  be  made  to  this  document  in  response  to safety-of-flight  or non-safety-of-
flight  issues.  Any  changes  will  result  in  a  revision  to  this  document.  Revisions  shall  be 
noted in the Record of Revisions and on the List of Revisions of this manual. 
  
						

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In  addition  to  the  revision  of  the  manual,  those  changes  categorized  as safety-of-flight 
shall  have  a  Service  Bulletin  issued  to  the  operator  providing  the  necessary  information 
to comply with or to correct the safety-of-flight issue. 
 
Replacement or revised copies of this manual can be obtained by contacting: 
 
Air Comm Corporation Service Department 
1575 W. 124th Ave. 
Westminster, CO.80234 
Phone No. 303-440-4075 Fax No. 303-440-6355 
Email: [email protected] 
12. Changes to Instructions for Continued Airworthiness 
Changes made to a line or paragraph of this document will be indicated by a vertical bar 
in the right hand margin. A complete page change will be indicated by a vertical bar next 
to the page number. 
 
(Example: Any change will appear with a vertical bar next to that change). 
13. Air Conditioner Features 
The  refrigerant  plumbing  for  this  system  installation  incorporates  insert O-Ring and 
TORQ LOK® fittings: 
 
A. INSERT  O-RING  FITTINGS: These fittings  have  formed  ends  that  along  with  an 
O-Ring create  a  seal.  Caution  when  assembling these  fittings; care  should  be 
taken  not  to  damage  the O-Ring (i.e.  nicking,  splitting,  or  crushing,  etc.).  These 
fittings  are  signified  by  a  green  band  placed  around  the  outside  diameter  of  the 
hose  or  tube  they  are  utilized  on. Black O-Rings  must  not  be used  on  these 
fittings. (See Chapter 7 for torqueing procedures). 
 
B. TORQ  LOK®  FITTINGS:  These  fittings  have  two  flat  mating  surfaces  that  along 
with  an  O-Ring  create  a  seal.  Caution  when  assembling  these  fittings; care 
should  be  taken  not  to  damage  the O-Ring (i.e.  nicking,  splitting,  or  crushing 
etc.). Green O-Rings  must  not  be  used  on  these  fittings. (See Chapter  7 for 
torqueing procedures). 
 
The system is also equipped with a Binary switch. This switch is designed to protect the 
system  against  over-pressure  situations,  or  under-pressure  in  the  event  of  refrigerant 
loss from the system. The switch also prevents the system from operating in low ambient 
temperatures below 50º F (10º C). 
 
The switch operating pressures are: 
 
 
  
						

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14.  Description of Vapor Cycle Air Conditioner and Installation 
 
This  section  contains  a  general  overview  of  a vapor-cycle  air  conditioning  system  and 
how  it  functions.  This  type  of  system  operates  in  a  closed  loop,  in  which  the  refrigerant 
absorbs heat from the cabin and ejects it into the outside air. The refrigerant then returns 
to  the  cabin  to  repeat  the  cycle.  The  operation  of  the  system  is  described  below (See 
Figure 1-2). 
 
Liquid refrigerant is contained in the receiver-drier under pressure from the compressor. 
The  receiver-drier  also  filters  the  refrigerant  through  a  material  know  as  desiccant.  The 
desiccant insures that the liquid refrigerant leaving this component is free of any water or 
other contaminants. 
 
The low pressure (suction) line from the compressor is attached to the evaporator lines, 
and  causes  the  refrigerant  to  be  pulled  out  of  the  receiver-drier  and  through  the 
expansion valves. The expansion valves serve as a controlled spray orifice, to spray the 
correct amount of refrigerant into the evaporator. This regulation of refrigerant allows the 
liquid to absorb the heat from the cabin air, and transform it to a vapor state just prior to 
its exiting the evaporator assembly. 
 
The  low  pressure  vapor  is  then  drawn  into  the  compressor  where  its  pressure  is  raised 
to approximately 200 psig (14.06 kg/cm) and its temperature to around 200º F (93.3º C). 
This  high  pressure/high  temperature  vapor  then  travels  to  the  condenser  (a  heat 
exchanger cooled by a flow of outside air). Heat is extracted from the refrigerant, and as 
it cools it condenses back into a liquid and flows into the receiver-dryer, ready to repeat 
the cycle.  
						

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15. Refrigeration Cycle Illustration 
 
 
 
 
Figure 1-2 – Refrigeration Cycle Illustration 
(NOTE: This illustration is provided as a reference only and may not match actual installation) 
 
 
 
High pressure liquid 
Low pressure vapor 
Low pressure liquid 
High pressure vapor 
Compressor 
Condenser 
Aft Evaporator 
Receiver- 
Drier 
Bypass 
Valve 
Expansion 
Valves 
Fwd Evaporator  
						

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CHAPTER 2 
AIRWORTHINESS LIMITATION SECTION 
 
1. Airworthiness Limitations 
 
The  Airworthiness limitations  section  is  FAA  approved  and  specifies  inspections  and 
other  maintenance  required  under  Sections  43.16  and  91.403  of  Federal  Aviation 
Regulations unless an alternative program has been FAA approved. 
 
“No airworthiness limitations associated with this type design change.” 
 
 
 
_______________________________________________________________
ACO Representative                                                                               DATE  
						

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CHAPTER 3 
INSPECTIONS AND OVERHAUL  
 
1. Inspection Requirements 
 
PERIODIC INSPECTIONS 
(Hours are aircraft time) 
Item Annual Every 25 
Hours of  
Operation 
Every 100 
Hours of 
Operation 
Special Inspection Information 
Evaporator Blower Hi/Lo 
Operation 
 
X 
  
X Check for operation 
 Condenser  
 Blower Motor, Scoop Door 
Actuator 
 
X 
 
 
 
X Check for operation 
 
Forward & Aft Evaporator 
Blower motor 
X  X  Check for operation in Hi and Lo 
settings 
Compressor Drive Belt 
 
 
X 
 
X 
 
X 
Check belt tension, and for signs 
of excessive wear (example: 
Glazing, Cracks, and exposed 
fibers) 
Air Conditioner 
Placards & Markings 
(see chapter 5) 
X 
 
 X 
Check for security and legibility 
Air Conditioner Compressor 
Assembly 
 
X 
 
X 
 
X 
Check for operation, security of 
attaching hardware, and signs of 
oil or refrigerant leaks. 
Air Conditioner Compressor 
Mount 
 
 
X 
 
 
 
X 
Check mount for cracks, and 
security of the attaching 
hardware.  
Plumbing and Fittings X  X Check for security and signs of oil 
or refrigerant leaks 
Air Conditioner Compressor 
drive pulley 
(mounted to tail rotor drive 
shaft) 
X  X Check for security of attaching 
hardware. 
 
Blower Electrical 
connectors X   
Visually inspect for signs of 
overheating. See sec. 2.I below 
for details. 
 
2. Inspection Procedures 
 
NOTE 
Refer  to  Chapter 4,  Location  and  Access,  to  locate  all  aforementioned 
components for inspection.  
						

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A. Inspection of the Fwd and Aft Evaporator Blower Motors: 
 
CAUTION 
Fans  are  designed  to  operate  with  the  resistance  of  the  entire  ducting 
system.  Operation  of  the  evaporator  fans  with  any  part  of  the  distribution 
system removed may cause permanent damage to the fan motor. 
 
WARNING 
Fans  may  take  up  to  10  seconds  to  start  after  the  switch  is  turned  on. 
Keep hands away from fan wheels or blades whenever switch is in Fan 
or A/C positions. 
 
At the Cockpits A/C Control Panel place the AIR COND switch in the FAN 
position and verify: 
 
1) That  both  the  fwd  and  aft  fans  are  activated  and  operating. Rotate  speed 
control knobs to verify blowers increase and decrease speed accordingly. 
2) That the condenser fan is non-operational. 
3) That  the  compressor  clutch  is  disengaged  and  the  “AIR  COND FAIL” 
message is not illuminated on the ADIU display. 
 
Place the AIR COND switch in the OFF position and verify: 
 
1) That both the fwd and aft fans deactivate. 
2) That  the  compressor  clutch  remains  disengaged  and  the “AIR  COND  FAIL” 
message is not illuminated on the ADIU display. 
 
B. Inspection of the Condenser: 
 
CAUTION 
This procedure requires the temporary installation of a jumper wire across 
the  terminals  of  the  binary  switch.  This  wire MUST be  removed  after  this 
inspection is accomplished.  
 
1) Visually  inspect  condenser  air  inlet  for  any obstructions  or  debris.  Airflow  in 
this area is critical for air conditioner operation. 
2) Disconnect  electrical  leads  from  the  binary  switch  and  install  a  jumper 
between the leads. 
3) Connect  28V  ground  power  to  the  aircraft  and  place  the  A/C  mode  switch  in 
the “A/C” position and verify: 
a. Condenser fan is activated and operating. This fan should pull air into 
the aircraft through the condenser assembly. 
b. Compressor  clutch  is  engaged  and  the  “AC  COMP  FAIL”  message  is 
not illuminated on the ADIU display. 
c. Disconnect  one  of  the  electrical  leads  from  the  binary  switch,  remove 
jumper  wire  and  verify that the  “AC  COMP  FAIL”  message  is 
illuminated on the ADIU display. 
4) Reconnect the electrical leads removed from the binary switch.