Aircraft Certification Staff Instruction (ACSI) No. 55 Issue 2
Aircraft Certification Staff Instruction (ACSI)
Subject: SHROUD TYPE CABIN HEATERS
It was found that the airworthiness requirements for these installations were not well defined, thus causing varied interpretations of the FAR's. Accordingly, this Airworthiness Staff Instruction has been generated to provide for uniform application of the appropriate standards.
The compliance requirements shall be in a checklist format as shown at Appendix A and are based on the Airworthiness Manual Chapter 527 (Normal Category Rotorcraft). The compliance checklist may be modified to suit each particular application.
For reference purposes, a CAR 6 equivalence to the Airworthiness Manual Chapter 527 has been added as Appendix B.
This Airworthiness Staff Instruction provides guidance to the Regional Airworthiness Engineers for an acceptable means by which Shroud Type Cabin Heaters may be approved in rotorcraft installations.
This ASI has been reissued to correct erroneous reference made to applicable airworthiness requirements. Changes are indicated by a vertical line adjacent to the left margin.
3.0 REFERENCE MATERIAL
- 4.1 Airworthiness Manual Chapter 527
- 4.2 Airworthiness Manual Chapter 529 (if applicable)
- 4.3 A.S.I. No.22 Supplementary Type Approval/Type Certificate Procedures
- 4.4 Applicable Type Approval
For an applicant requesting Supplemental Type Approval, Limited STA or "one-off mod" the procedure as detailed in Airworthiness Staff Instruction No. 22 (Supplementary Type Approval/Certificate procedure) shall be followed in addition to those outlined in this document.
4.2 Compliance Substantiation
The method of substantiation for each compliance item shall be by test, analysis, or inspection and shall be identified by the symbols "T", "A", and "I", respectively, on the compliance checklist.
The type of substantiation for each item shall be established at the start of the program. It may be determined that certain requirements on the compliance checklist are not applicable. Such items shall be identified and their exclusion justified. Similarly, should the applicant request an alleviation of requirement, the item shall be identified and accompanied by a justification note.
The tests and analyses shall be substantiated by reports detailing the methods of compliance and be identified on the checklist. The inspection items shall be supported by drawings, including installation drawing.
The approval shall then be shown against each item once requirements are satisfied.
It should be ensured that the applicant understands the compliance items including any Additional Airworthiness Requirements.
4.3 Compliance Review
Clarification of the following items in the compliance checklist is deemed necessary to show the intent of the requirements. The remaining checklist items are considered self-explanatory.
Item 18: 527.831 — Ventilation
Item 19: 527.853 (A) — Compartment Interiors
To prevent possibility of carbon monoxide (CO) emissions with this type of heater system, the installation of CO detectors is mandatory to satisfy Item 18. AlSo, should the plumbing be exposed to high heat or flame, no noxious gases should be transmitted to the cockpit via the plumbing due to material degradation. Furthermore, the plumbing material should be "flash resistant" if exposed to direct flame.
Item 21: 527.861 — Fire Protection of Structure, Controls and other Parts
To allow time to activate the Emergency Shut off Valve and turn off the shroud heater system.
Item 24: 527.1041 — Cooling - General
Item 25: 527.1043 — Cooling Tests
Item 26: 527.1045 — Cooling Test Procedures
While exhaust gas temperatures may remain unchanged with the addition of a shroud heater, alteration of the heat rejection rate is possible and may cause a temperature redistribution in the casing.
A temperature rise and the possible formation of hot spots would be detrimental to the engine and eventually affect the service life.
It is also possible that the shroud may decrease the . casing temperature which would also affect the engine and its operation.
The following temperature survey is recommended as a means of compliance:
- Shroud Installed:
- Heater On
- Heater Off
- Shroud Removed
Suitable test conditions for such a survey would be in hover, rearward flight, climb and takeoff.
To demonstrate that Flight Manual limitations are not exceeded and that no maximum temperature at which removal of the shroud heater is necessary, a hot day test shall be done.
Further, to demonstrate that the shroud does not abnormally cool the casing, a cold weather test is advisable.
Should the survey results be unacceptable to Transport Canada, applicant may contact the engine manufacturer to seek their opinion.
While the applicant is not required to receive consent from the manufacturer for such a modification, the applicant's standing would be better should his product be endorsed.
Item 30: 527.1193 — Cowling and Engine Compartment Covering
This paragraph covers any change to the cowling for any optional equipment (i.e.: winter cowlings).
Item 32: 527.1309(b) — Equipment, Systems and Installations (Hazards)
If a fan is used, rotor burst data should be submitted for any high speed fan. Also an explosive proof test of the fan motor would be required for an installation in an area that can be contaminated by explosive fumes.
Original signed by:
James A. Torck
Director, Airworthiness Branch
SHROUD TYPE CABIN HEATERS COMPLIANCE CHECKLIST
|1||527.301||(A), (B), (C) Loads|
|2||527.303||Factors of Safety|
|3||527.307||(A) Proof of Structure|
|4||527.321||Flight Loads General|
|5||527.337||Limit Manoeuvering Load Factor|
|6||527.341||Gust Loads (If Applicable)|
|7||527.561||(B)(3) & (C) General|
|11||527.321||Flight Loads General|
|12||527.609||Protection of Structure|
|14||527.613||Material strength Properties and Design Values|
|15||527.623||Bearing Factors (If Applicable)|
|17||527.671||Control System - General|
|18||527.831||(A) & (B) Ventilation|
|19||527.853||(A) Compartment Interiors|
|20||527.859||(A) & (B) Heating Systems|
|21||527.861||Fire Protection of Structure, Controls and Other Parts|
|22||527.863||Flammable Fluid Fire Protection|
|24||527.1041||Cooling - General|
|26||527.1045||Cooling Test Procedures|
|27||527.1121||Exhaust System - General|
|30||527.1193||Cowling & Engine Compartment Covering|
|31||527.1301||(A),(B),(C),(D) Function and Installation|
|32||527.1309||(b) Equipment, System & Installations Hazards|
|33||527.1351||(A)(1)&(2) Electrical System and Equipment - General|
|34||527.1351||Circuit Protective Devices|
|37||527.1529||Instruction for Continued Airworthiness|
|38||527.1541||Markings & Placards General|
|39||527.1555||(A)&(D)(2) Control Markings|
|40||527.1559||Limitations Placard (If Applicable)|
|41||527.1581||Rotorcraft Flight Manual - General|
|45||Applicable Addition Airworthiness Requirements/Special Conditions (Review of Type Approval or Type Certificate)|
* Denoted by:
- "T" (Test)
- "A" (Analysis)
- "I" (Inspection)
SHROUD TYPE CABIN HEATERS CAR 6 EQUIVALENCE
|1||527.301||(A), (B), (C), Loads||6.200 (A)|
|2||527.303||Factor of Safety||6.200 (B)|
|3||527.307||(A) Proof of Structure||6.202|
|4||527.321||Flight Loads General||6.210|
|5||527.337||Limit Maneuvering Load Factor||6.212|
|6||527.341||Gust Loads (If applicable)||6.213|
|7||527.561||(B)(3) & (C) General||6.260|
|12||527.609||Protection of Structure||6.304|
|14||527.613||Material Strength Properties and Design Values||6.306|
|15||527.623||Bearing Factors (If Applicable)||6.307 (C)|
|16||527.625||Fitting Factors||6.307 (D)|
|17||527.671||Control Systems - General||6.320|
|18||527.831||(A) & (B) Ventilation||6.358|
|19||527.853||(A) Compartment Interiors||6.381|
|20||527.859||(A) & (b) Heating Systems||6.383|
|21||527.861||Fire Protection of Structure, Controls and Other Parts||6.384|
|22||527.863||Flammable Fluid Fire Protection||5555|
|24||527.1041||Cooling - General||6.450|
|26||527.1045||Cooling Test Procedure||5555|
|27||527.1121||Exhaust System - General||6.460|
|30||527.1193||Cowling & Engine Compartment Covering||6.484|
|31||527.1301||(A), (B), (C), (D) Function and Installation||6.6006.601|
|32||527.1309||(b) Equipment, Systems & Installations (Hazards)||6.620 (A)|
|33||527.1351||(A)(1) & (2)Electrical Systems and Equipment - General||6.6206.6216.622|
|34||527.1357||Circuit Protective Devices||6.625|
|37||527.1529||Instructions for Continued Airworthiness||6.719|
|38||527.1541||Markings & Placards General||6.730|
|39||527.1555||(A) & (D)(2) Control Markings||6.737|
|40||527.1559||Limitations Placard (If Applicable)||6.638 (D)|
|41||527.1581||Rotorcraft Flight Manual - General||6.740|
|45||Applicable Additional Airworthiness Requirements/Special Conditions||5555|
Note: 5555 - denotes that requirement is not in CAR 6
- Date modified: