AEROSPACE 

Bombardier Inc. 

400 chemin de la Côte-Vertu West 

Dorval, Québec, Canada H4S 1Y9 

www.bombardier.com 

TEL 514-855-5000 

FAX 514-855-7401 

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 
2 

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 NPRM2 on the implementation delay. We have also previously submitted a petition for 

rulemaking in 2009 on this same issue3. 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. 
3 

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. 

5 

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) position6 18 * * * * * * * * * * * * * * * 

16. Lateral control surface(s) position7 18 * * * * * * * * * * * * * * * 

17. Yaw control surface(s) position8 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. 
6 

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 
7 

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.