BT0016-01 MW 2005-07 Page 1 of 2 Revised 2013-06-07 

### M INUTES OF 

### M EETING

PROJECT TITLE: 

### C Series

FROM: Carina Groombridge, Airworthiness PHONE #: (514) 855-5000/ 63773

SITE: Montreal BAN DATE OF MEETING: 2013-06-07
LOCATION: BAN 1 South, 3rd Floor, Room P-8-84,
SUBJECT: FAA/TCCA/BA review of FAA queries on 25.841 exemption - Pneumatics

OBJECTIVES: Review FAA concerns (listed in letter dated April 30, 2013 attached) to BA petition for exemption

DISTRIBUTION ATTENDEES INFORMATION NAME SITE NAME SITE BA: BA: Carina Groombrid g e ( CG ) BAN Keith Barnett Carlos Lima ( CL ) BAN Carlos Rivera Keith A y re ( KA ) BAN Jean Brousseau ( JB ) BAN FAA: Francois Godin ( FG ) BAN Christo p her Alfano Victor Wicklun d TCCA: Jac q ues Leves q ue ( JL ) OTT David Johns ( DJ ) OTT
FAA: Ser g e Na p oleon ( SN ) Clinton Jones ( CJ ) Ste p hen Ha pp enn y ( SH ) Fabio Buttitta ( FB )

ITE SUBJECT COMMENTS/ ACTIONS 1. Overview BA submitted a petition for exemption to 25.841, November 9, 2012. FAA has provided a letter, dated April 30, 2013 with a list of queries in response to the BA petition. This meeting was called in order to review the FAA questions and clarify the FAA expectations. This will ensure the BA res ponse will be in-line w ith the expectations and respond with clarity. 2. Question (1) To satisfy the FAA concern BA will provide the following information/clarification in the BA formal response to the FAA letter.

- Emergency descent profile rate

- Critical hole size to meet 841(a)

- The open area as the result of a 1/3 rotor fuselage penetration and the associated probability of occurrence. 3. Questions (2) BA to provide an assessment of the se verity of the depressurization to the occupants. The BA letter will stipulate the timeframe when BA will share this information to FAA.

### M INUTES OF 

### M EETING FOR 

### : 2013-06-07 FAA/TCCA/BA REVIEW OF 

### FAA QUERIES ON 

### 25.841 EXEMPTION 

### - P NEUMATICS

BT0016-01 MW 2005-07 Page 2 of 2

ITE SUBJECT COMMENTS/ ACTIONS 4. Question (3) Conservative approach taken by BA is acceptable. BA to provide in the response letter add itional clarification on EDM for information only. 5. Question (4) BA confirmed their intention to conduct flight test certification demonstration of the proposed flight test emergency descent procedures. 6. Question (5) BA re-iterated that information will be provided on EDM. 7. BA requested clarification on interpretation of following Interim Policy Statement: BA highlighted their interpretation of the FAA Interim Policy ANM-03-112-16 dated March 24, 2006 related to failures consideration following UEF. Excerpt from Policy memo ANM-03-112-16; “In analyzing system and structural damage caused by fragments from an UEF, additional structural damage can be assumed to be limited to that engine. Regarding engine powered systems, other than losing the thrust, engine air bleed, and engine accessory power on the engine suffering the UEF, the operation of other airplane systems can be assumed to be normal. Ther efore, the airplane should be capable of performing a V MO

/M MO emergency descent (i.e., spoilers fully deployed if appropriate, maximum descent rate, V MO

/M MO speed.) As explicated in BA Exemption Request Form; “In calculating the descent capability of the aeroplane in order to meet the revised cabin altitude conditions in d), the loss of the failed engine’s c ontribution as a source of power to the systems enabling the descent will be considered (i.e. if losing power on one engine results in loss of one hy draulic system engine-driven-pump, the descent rate will be based on the capabilities of the remaining hydraulic systems with the backup power sources, such as the ACMP or PTU). Systems degradation due to debris damage from the actual UEF (e.g. hydraulic line rupture, wiring damage, etc...) will not be considered. FAA confirmed that BAs interpretation is acceptable. 8. Action ACTION: BA to respond to FAA letter April 30, 2013, using the clarification obtained at this 2013-06-07 telecom. 9. Submission of BA response BA requested to submit BA response electronically contrary to the statement in the FAA letter. FAA (SH) confirmed electroni c submission is acceptable, hard copy to follow. Note: the BA response will be provided on or before June 28, 2013 as agreed in email communication.

Attachments: FAA letter April 30, 2013.1 Transport Airplane Directorate 1601 Lind Avenue, S.W. Renton, W ashington 98057

- 3356

April 30 , 2013

Mr. Keith Barnett Airworthiness Manager, CSeries Bombardier Aerospace 400 CÔTE

- VERTU Rd. West Dorval, QUÉ BEC, Canada H4S 1Y9
Dear Mr. Barnett ;
The Federal Aviation Administration ( FAA ) has completed our review of your pe tition for exemption from requirements of Title 14, Code of Federal Regulations (14 CFR) 25.841(a)(2)(i) and (a)(2)(ii) at Amendment 25

- 87 for the Bombardier M odel s BD

- 500

- 1A10 (CS100) and BD

- 500

- 1A11 (CS300) airplanes , dated No ve mber 9, 2012

. The exemption, if granted, would provide relief from cabin decompression requirements following an uncontained engine failure enabling these model airplanes to operate where they are most efficient, thereby reducing fuel burn and producing lower emissions. We have determined that we need more information before we can process your petition . Please note that we have asked for similar information from other petitioners on past petitions for exemption to this rule.
Bombardier is asked to provide the following information : (1) On page 2 of 2 , Bombardier states that, “ The CSeries will meet requirements of 14 CFR § 25.841(a)(2)(i) and (ii) for all system and structural failures but not for all types of engine failures ; for some UEFs that result in pressure vessel penetration by fragments causing a very large hole, the design of the CSeries does not meet t he requirements of 14 CFR § 25.841(a)(2)(i) and (ii). ....” **Question/Request:** FAA acceptance of the increased level of risk from a rapid decompression is predicated on the probability of the failure event. While Bombardier did include some estimates of probability of uncontained engine debris, t he Bo mbardier petition did not include any

information on the resulting holes from uncontained engine failures versus probability

of occurrence (e.g., hole sizes versus probability of rapid decompression event per flight hour or departure). Bo mbardier provided no results of their decompression anal ys is (e.g., airplane cabin pressure time history) or comparisons with d ata from
u ncontained e ngine d ebris t rajectory studies. Bo mbardier did not provide an estimate of the critical hole size which would result in a decompression which the airplane would successfull y meet the cabin pressure limits contained in 14 CFR 25.841(a)(2). Bo mbardier2

did not provide any

estimates of the resulting fuselage hole size versus probabi lity of
occurrence. (2) On several pages Bombardier refers to the Aviation Rulemaking Advisory Committee (ARAC) Mechanical S ys tems Harmonization Working Group ( MSHWG ) report , but nowhere in the petition does Bombardier provide an assessment of the severi ty of the depressurization to the occupants as recommended within that report

. **Question/Request:** FAA has requested that all petitions for exemption to § 25.841 follow the general guidance in FAA Policy Memo randum ANM

- 03

- 112

- 16, Interim Policy on High Altitude Cabin Decompression (Reference Amendment 25

- 87). Within the guidance, FAA describes the use of a physiological model that affords some measure of the severit y to the occupants from a rapid decompression. We have requested that all petitioners ut ilize models similar to those from the ARAC MSHWG Report on § 25.841(a)(2) and (3), August 2003. Bo mbardier did not provide an y estimates of the severit y to the occupants (e.g., the Depressurization Exposure Integral (DEI) method in the ARAC MSHWG Report). Bo mbardier should provide this material. (3) In the petition Bombardier states that “.... BA has incorporated design features that appropriately address the risk to safety following an UEF, as recommended by the FAA Interim Policy above. In the unlikely e vent of an UEF, the CSeries preserves an even higher level of safety relative to previously certificated airplanes due to its higher descent capability (in line with the time

- above

- altitude FAA guidance and the recommendations of the ARAC), and other desig n feature such as an Emergency Descent Mode (EDM) which will provide an additional margin of safety by initiating a descent automatically if there is no flight crew action following a loss of cabin pressure, as well as an automatic pressure demand mask (FA A approved for 41,000 ft. ) for the pilots which will be certified to comply with 14CFR § 25.1441(d). ..... ” **Question/Request:** T he primary means to ensure occupant survivabilit y (following a rapid depressurization event) rests in quickly bringing the occupants to a cabin pressure where they can survive (i.e., a lower cabin pressure altitude ) . Policy Memo ANM

- 03

- 112

- 16 requests that, “The petitioner should provide information about any existing or new design features that provide enhanced airplane emerg ency descent rates and occupant survivability. ” Bo mbardier has not provided m any details o n mitigating design and/or operational features that offset the increased level of risk at high altitudes (e.g., Does the CSeries incorporate an y redundant s ys tems t hat provide additional descent speed capability , or include additional containment protection from engine debris , etc. ? ) and, Bo mbardier did not provide an y estimated descent speed data or cabin pressure exposure plots (i.e., cabin pressure altitude versus time and airplane flight pressure altitude versus time) following worst case uncontained engine rotor failure events. Please include all assumptions that have been used in the anal ys is (e.g., hole size, environmental control s ys tem pack operation, availab le h ydraulic/electrical/pneumatic power to operate control surfaces, discharge coefficient of hole, other airplane leakage, etc.). In addition, Bo mbardier did not provide any estimated airplane descent rates which cover the operating envelope (e.g., bounda ries set b y maximum and minimum airplane weight)

. Also , Bombardier did not provide any airplane3

performance predictions to show that the CSeries can successfull y meet the cabin pressure exposure limits in the Policy Memo ANM

- 03

- 112

- 16. (4) Bombardier i s asked to confirm their intention to conduct flight test certification demonstration of the proposed flight test emergency descent procedure s (both manual and EDM) recommended in the AFM, per Policy Memo ANM

- 03

- 112

- 16. (5) On page 12 of 14, Bombardier states, “... h) The CSeries will have an Emergency Descent Mode (EDM) which will provide an additional margin of safety by initiating a descent automatically if there is no flight crew action following a loss of cabin pressur e or when the flight crew pushes the EDM button. ....” **Question/Request:** Bombardier is asked to provide additional information on the EDM sy stem . Please provide an explanation of associated hardware and software architecture, sy stem reliabilit y, means to exclude false activation, etc. Please do not post proprietary information on the Regulations.gov public website. Either mail it to us by

certified mail or fax it to us at 425

- 227

- 1320
Please provide the supplemental information for Bombardier M odel s BD

- 500

- 1A10 (CS100) and BD

- 500

- 1A11 (CS300) airplanes and address it to:

Transport Airplane Directorate Federal Aviation Administration Attn. Stephen Happenn y/ ANM

- 112 1601 L ind Ave. SW Renton, WA 98057
If we do not hear from you within 30 days, we will close the project without notify ing y ou further. In the meantime, should y ou have an y questions or concerns regarding this request, please contact Stephen Happenn y, ANM

- 112 , at 425

- 227

- 2147 , or e - mail, Stephen.Happenn y @faa.gov.
Sincerel y,

Victor W icklund Manager, Propulsion & Mechanical Sy stems Branch Transport Airplane Directorate , Aircraft Certification Service