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### June 22, 2011

Re: Petition for Rule Change
Bombardier Aerospace submits the following petition for rulemaking to revise specific digital flight data recorder (DFDR) parameter recording requirements in footnote 18 to Appendix F of 14 CFR Part 135. This revision would allow up to nine Bombardier Aerospace BD-700-1A10 and BD-700-1A11 aircraft, serial numbers 9423-9431 inclusive, to operate under Part 135 while recording seven flight data parameters at lower data rates than those published in Appendix F. The justification for this amendment is the extremely high cost to make the required upgrades in the face of the introduction of a replacement avionics suite that limits the applicability of these upgrades to a very small number of aircraft. The proposed regulatory change is detailed in Appendix A to this petition.
The nine BD-700 aircraft identified above are equipped with the Honeywell Primus 2000XP system and are compliant with Part 135 DFDR requirements for aircraft manufactured prior to December 6, 2010. Manufacture of aircraft with this avionics package stopped in February of 2011, less than 3 months after the implementation date for increased data recording rates in DFDR systems under amendment 121 to Part 135 (amendment 135-121). Apart from these seven flight data parameter recording rates, all other applicable requirements introduced in this amendment, as well as those of amendments 91-300 and 135-113, were complied with in the nine affected aircraft.
As implemented in the BD-700, this system cannot be further upgraded to meet current data rate recording requirements without an unwarranted, non-recurring expenditure exceeding $2.9 million, and recurring costs of almost $100 000 per aircraft with no direct impact on operational safety. An explanation of the technical obstacles to this upgrade is given in Appendix B to this petition. Docket Operations, M–30 U.S. Department of Transportation 1200 New Jersey Avenue, SE Room W12–140, West Building Ground Floor, Washington DC 20590-0001

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While these nine aircraft cannot practically be made compliant, all subsequent aircraft produced from aircraft serial number 9432 onward are equipped with the Rockwell Collins Proline Fusion avionics suite, which includes a DFDR system compliant with the 16 Hz data rate specifications of the original 2005 NPRM. 1 

### Introduction of the Proline Fusion suite ensures that no additional BD-700 aircraft will need relief from these DFDR requirements.
Bombardier Aerospace has previously submitted comments identifying this specific issue to the 2010 NPRM 2 

### on the implementation delay. We have also previously submitted a petition for rulemaking in 2009 on this same issue 3 

### . While these proposals were rejected, we think two key issues were not addressed at the time of the latest Final Rule and could not be resolved within the 60-day window to petition for reconsideration:

x The number of affected aircraft was unknown. Although it was estimated that 15 aircraft would be affected, the Rockwell Collins Proline Fusion avionics suite was introduced after only 9 non-compliant aircraft were produced.

x Certification of the Rockwell Collins Proline Fusion avionics suite had not yet been completed, lending uncertainty to any claims of the number of affected aircraft, and the overall impact of any exception made for the aircraft. With this system fully certified, we can now state with certainty the number of aircraft affected by this petition.
In rejecting the petition of one operator, the FAA noted that “under its considerable experience with flight recorder system upgrades, promises of modification rarely meet the original predictions.” 4 

### We agree that development programs often encounter unexpected delays. Accordingly, the completion of this program and the establishment of known limits on the number of non-compliant aircraft are significant when determining the impact of a regulatory change.

1 Docket No. FAA-2005-20245-0002.

2 Docket No. FAA-2005-20245-0091.

3 Docket No. FAA-2009-0441-0001.

4 Docket No. FAA-2009-0050-0003.

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While it is also possible to pursue relief from these requirements through operator petitions for exemption, the FAA has stated in the past that “exemptions are by their nature designed for relief for defined periods.” 5 

### We do not foresee this relief being temporary owing to the impracticality of developing a compliant solution. Furthermore, DFDR recording parameter requirements are unlikely to be dependent on the operator or their operating procedures; a rulemaking change is the most appropriate avenue to address this situation.
Strict application of the current requirements would significantly affect the resale value of these aircraft as they would be limited to Part 91 operations only. While the FAA has previously stated that it “does not accept business opportunity as a basis for relief from safety regulations” 6 

### , we do not agree with the premise that a non-compliant flight data recorder is a safety deficiency. The decision of the FAA not to make this requirement retroactive for all Part 135 aircraft would appear to be consistent with this position. Amending Part 135 per this petition would not adversely affect the safety of the aircraft involved, as this change concerns the sampling rate of specific parameters and does not impact operational safety of the subject aircraft.
Bombardier Aerospace nevertheless recognizes the contribution of flight data recorders to accident and incident investigations, and ultimately to the safety of the design and operation of future aircraft. However, the cost to make this particular legacy DFDR system compliant with current regulations would be extremely high and disproportionate to the potential benefit. This upgrade would apply to no more than nine aircraft in an operating fleet of 431 BD-700s equipped with the same Honeywell avionics suite, or 2% of the fleet, the benefits to aviation safety and the public interest would be negligible. When considering that 10-15% of the BD-700 fleet has historically operated under Part 135 at any given time, the benefits are reduced even further, as it would be extremely unlikely that more than two of these nine aircraft would be concurrently operating under Part 135 and subject to these data rate requirements.

5 Docket No. FAA-2008-0329-0003.

6 Docket No. FAA-2009-0050-0003.

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## Appendix A – Proposed Change to Regulation Appendix F to Part 135—Airplane Flight Recorder Specification
Note: the parameters below are unchanged and are listed for reference only.

Parameters Range Accuracy (sensor input) Seconds per

sampling interval Resolution Remarks
* * * * * * * * * * * * * * * * * * 12a. Pitch control(s) position (nonfly-by-wire systems) 18 * * * * * * * * * * * * * * *
* * * * * * * * * * * * * * * * * *13a. Lateral control position(s) (nonfly-bywire) 18 * * * * * * * * * * * * * * *
* * * * * * * * * * * * * * * * * * 14a. Yaw control position(s) (nonfly-by-wire) 5 18 * * * * * * * * * * * * * * *
* * * * * * * * * * * * * * * * * * 15. Pitch control surface(s) position 6 18 * * * * * * * * * * * * * * * 16. Lateral control surface(s) position 7 18 * * * * * * * * * * * * * * * 17. Yaw control surface(s) position 8 18 * * * * * * * * * * * * * * *
* * * * * * * * * * * * * * * * * * 88. All cockpit flight control input forces (control wheel, control column, rudder pedal) 18 * * * * * * * * * * * * * * *

18 -For all aircraft manufactured on or after December 6, 2010, excepting serial numbers 9423-9431 inclusive for Bombardier Aerospace BD-700-1A10 and -1A11, the seconds per sampling interval is 0.125. Each input must be recorded at this rate. Alternately sampling inputs (interleaving) to meet this sampling interval is prohibited.

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## Appendix B – Technical Limitations of the BD-700 DFDR System The technical issues with the flight data recorder rates of the Honeywell Primus 2000XP avionics platform as installed in the BD-700 product line are unchanged from our previous petitions:
The BD-700 (Global) aircraft’s Avionics Standard Communication Bus (ASCB) system transmits data between the Line Replacement Units (LRUs), including parameter data to the Data Acquisition Units (DAUs). The DFDR connects to DAU 4 to receive data from ARINC 717 bus. Bombardier has assessed design alternatives, both within the existing aircraft architecture and options bypassing the ASCB.
To meet strict compliance with the final rule’s increased recording rate for parameters 13 and 88 using existing architecture, remapping of the source equipment (ASCB and all LRUs communicating with the ASCB), and potential LRU hardware upgrades would be required. The scope of this modification is extensive, and not practical given the scope and schedule established by the final rule. To bypass the ASCB would require hardware installations (additional LRU and/or data bus) further to what is currently available on the source equipment. Sending the data independently and bypassing the ASCB creates a time lag that differs from the data being sent over the ASCB.
The time required to receive, process, and transmit the bits will lead to a time lag between parameter data. Parameters 13 and 88 will not be synchronous with the other DFDR data transmitted on the ASCB.
Additionally, parameters 12a (pitch control position), 14a (yaw control position), 15 (pitch control surface position), 16 (lateral control surface position) and 17 (yaw control surface position) remain non-compliant with the current data rate requirements. Data rates for these parameters vary from 1-4 Hz, depending on the parameter and are summarized in Table 1. While it would be possible to make these data rates compliant without remapping of the ASCB, the non-recurring cost estimate from the supplier to develop a partially-compliant solution is approximately $1.5 million dollars, in line with development costs seen in other Bombardier Aerospace product lines. This avenue was not pursued as it would require a significant expenditure of resources to produce a system that was still non-compliant. The proposal was also made using the original April 6, 2010 implementation date of the Final Rule, when up to 45 aircraft would have been affected. With 9 aircraft affected by the current scenario, this option is no longer practical. The

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non-recurring cost estimate for a fully-compliant avionics upgrade that included ASCB reprogramming was $2.9 million.
Parameter (# Inputs) Current Parameter Rate Required

Parameter Rate Maximum Parameter Rate Available Without Repartitioning ASCB
Pitch Control Position (2) 4 Hz 8 Hz 10 Hz Lateral Control Position (2) 4 Hz 8 Hz 5 Hz Yaw Control Position (1) 4 Hz* 8 Hz 10 Hz Pitch Control Surface Position (2) 4 Hz 8 Hz 10 Hz

Lateral Control Surface Position (2) 4 Hz 8 Hz 10 Hz

Yaw Control Surface Position (1) 4 Hz* 8 Hz 10 Hz
Cockpit Flight Control Input Forces (8) 1 Hz 8 Hz 5 Hz

Table 1: Available data rates on aircraft with the Honeywell Primus 2000XP avionics suite as implemented in the Bombardier BD700 product line. * - Interleaving used on 2Hz signal.


### These estimates did not include re-engineering costs for the physical installation and relocation of components, or for related changes to documents such as the maintenance instructions and illustrated parts catalogue. Scheduling estimates indicated the modifications would not be certified until well after the nine affected aircraft had been delivered, and would require an in-service retrofit program at additional cost.
It is notable that the 2005 NPRM used an estimated re-engineering cost of $35 million for all affected aircraft operating in the United States, and a typical installation cost of $10 640. As noted above, in the case of the BD-700 the estimated re-engineering cost to make the nine affected aircraft compliant with current requirements is approximately $2.9 million, which exceeds 7.5% of the total cost estimated by the FAA. Furthermore, the installation costs of almost $100 000 per aircraft noted above are almost ten times the FAA’s initial estimate used in its cost-benefit analysis.