U.S. Department

of Transportation **FEDERAL AVIATION ADMINISTRATION**  Office of Aviation Policy and Plans Washington, D.C. 20591



### FINAL **REGULATORY EVALUATION**

**ACTIVATION OF ICE PROTECTION**

**(14 CFR Part 121) OFFICE OF AVI** **ATION POLICY, PLANS AND MANAGEMENT ANALYSIS AIRCRAFT REGULATORY ANALYSIS BRANCH, APO**  **- 320** 

**George Thurston June 29, 2010** 2

**TABLE OF CONTENTS**

I. INTRODUCTION 3 II. BACKGROUND 3 III. THE COSTS ESTI MATE 5 IV . THE BENEFITS ESTIMATE 1 9 V. BENEFIT - COST SUMMARY 2 4 VI . APPENDIX3

**I. INTRODUCTION** This final rule will amend the regulations applicable to operators of certain airplanes used in § 121 air carrier service and certificated for flight in i cing conditions . The standards w ill require either the installation of ice detection equipment or changes to the Airplane Flight Manual (AFM) to ensure timely activation of the airframe ice protection sy stem. This final rule is the result of information gathered from a review of icing accidents and incidents, and it is intended to improve the level of safety when airplanes are operated in icing conditions. This final rule is also responsive to National Transportation Safety Board (NTSB) recommendation A - 07 - 14 . **II. BACKGROUND** On October 31, 1994, at 15 : 59 Central Standard Time, an Avions de Transport Regional model ATR - 72 , operated by Simmons Airlines, Incorporated, and doing business as American Eagle flight 4184 , crashed during a rapid descent after an uncommanded roll excursion. The plane crashed into a so yb ean field near Roselawn, Indiana . The FAA, Aerospatiale, the French Direction Générale de l’Aviation Civile, Bureau Enquete Accident, National Aeronautics and Space Administration (NASA), Natio nal Transportation Safety Board, and others conducted an extensive investigation of this accident. This investigation concluded that freezing drizzle conditions created a ridge of ice aft of the deicing boots and forward of the ailerons, which resulted in uncommanded roll of the airplane.4

This accident and investigation prompted the FAA to initiate a review of aircraft in - flight icing safety and determine changes that could be made to increase the level of safety . In May 1996, the FAA sponsored the Inter national Conference on Aircraft Inflight I cing, where icing specialists recommended improvements to increase the level of safety of aircraft operating in icing conditions. The FAA reviewed the conference recommendations and developed a comprehensive multi - ye ar icing plan. The FAA Inflight Aircraft Icing Plan, dated April 1997, described various activities we were contemplating to improve aircraft safety when operating in icing conditions. In accordance with the FAA Inflight Aircraft Icing Plan, the FAA t asked the Aviation Rulemaking Advisory Committee (ARAC), through its Ice Protection Harmonization Working Group (IPHWG), to consider the need for ice detectors or other acceptable means to warn flight crews of ice accretion on critical surfaces requiring crew action. In November 2009, the FAA published a notice of proposed rulemaking (NPRM) for part 121 Activation of Ice Protection. The comment period for the proposed rule closed February 2010. The FAA’s response to economic comments is contained in the preamble to this final rule. This final rule is based on the ARAC’s recommendations to the FAA . The final rule will require either the installation of ice detection equipment or changes to the Airplane Flight Manual (AFM ) to ensure timely activation of the airframe ice protection sy stem. **II.1. NTSB Safety Recommendations**  This final rule addresses NTSB safety recommendation A - 07 - 14 on the subject of airframe icing. That NTSB safety recommendation result ed from a Cessna Citation 560 series airplane ac cident near Pueblo, Colorado, which occurred on February 16, 2005, in which the airplane crashed and eight people died. The accident airplane had been operating in icing5

conditions and the flight crew had not activated the airframe ice protection system d uring approach as required b y the AFM for the operational conditions. The NTSB recommended that manufacturers and operators of pneumatic - deicing - boot - equipped airplanes be required to revise their operating manuals and training programs to emphasize that leading edge deicing boots should be activated as soon as the airplane enters icing conditions. **III. THE COSTS ESTIMATES**  **III.1 Discussion of the**  **Final Rule**  The final rule consists of two parts: (1) 14 CFR p art 121.321 Sections (a) (1) , ( a) (2) , or (a)(3) which w ill affect all p art 121 operated airplanes with a certified MTOW of less than 60,000 pounds. These sections will mandate when the pilot is to activate the Ice Protection Sy stems ( IP S ) . All part 121 airplanes certificated for flight in icing conditions, currentl y have an IPS. A primary

or advisory

ice detection s ys tem (IDS) is a device that alerts the flight crew to activate the IPS. Not all part 121 airplanes certificated for flight in icing conditions, have IDS. For airplanes equipped with an IDS, thi s final rule will allow either automatic or manual cycling by the flight crew each time ice is detected. For airplanes not equipped with an IDS, this final rule will mandate that when the airplane is operating in conditions conducive to airframe icing, th e IPS must be activated prior to and operated during all phases of flight except take - off and cruise (unless prohibited by

the AFM). Conditions conducive to airframe icing is defined as visible moisture at or below a static air temperature of +5 degree C or a total air temperature of + 10 degree C .6

(2) 14 CFR p art 121.321 Sections (b), (c), (d), and (e) which affects all 14 CFR Part 121 operated airplanes with a certified MTOW of less than 60,000 pounds. These sections will mandate adding the procedures for sa fe and continuous operations of the IPS in the AFM . Two elements drive the overall cost estimate. They are: (1) the costs per airplane to the operators required to implement sections (a)(1), (a)(2), or (a)(3) of this final rule; and (2) the estimate of the number of affected airplanes; including a snapshot of the current active fleet, a forecast of airplanes affected b y the final rule entering the fleet, and a forecast of the retired affected airplanes during the anal ys is period. I f the AFM prohibit s the procedur es of (a)(3)(i) , then section (b) specifies procedures . Section (c) requires AFM procedures for compliance with the final rule. Section (d) requires procedures for operating an IPS after its initial activation. Section (e) requires approval of sy stem in stallations and Airplane Flight Manual procedures through an amended or supplemental ty pe certificate. The cost s for section (b), (c), (d) and (e) are included in the costs estimated for section (a)(1), (a)(2), or (a)(3) of this final rule. All costs, dis cussed in the following estimates, are based in 20 10 dollars and the present value discount rate is seven percent as mandated by the Office of Management and Budget. We also performed a sensitivity anal ys is with a three percent present value factor. The FAA anal yz ed the costs and benefits of this final rule over a 2 0 - ye ar anal ys is period after the promulgation of the final rule . A 20 - ye ar anal ys is interval would capture nearl y all of the lifetime costs and benefits of the final rule. **III.2 Assumptions** 7

In order to estimate the potential costs and benefits of the final rule, we have made the following assumptions: (1) The base ye ar is 20 10 . (2) This final rule will be effective in 2011. (3) The compliance date of the rule is 24 months from the effective date of the final rule. (4) The anal ys is period extends for 2 0 years from 201 3 through 20 3 2 . We believe this anal ys is period captures nearl y all of the expected benefits and costs. (5) All monetary

values are expressed in constant 2010 dollars. The present value of the po tential 10 - ye ar benefit stream was calculated b y discounting the monetary values using a three and seven percent present value rate over the 201 3 to 20 3 2 analysis period . (6) The value of an averted fatality is $ 6.0 million. 1 (7) The FAA used $ 104.99 hourly rate f or a mechanic/technician working for an airplane manufacturer or modifier and the $ 86.48 hourl y rate for an engineer working for an airplane manufacturer or modifier. These hourl y rates include overhead costs. 2 **III.3 Costs Required to Implement**  **Sections (a)(1), (a)(2), or (a)(3)**  Exhibit 1 illustrates the chain of events leading up to the decision on whether an operator will incur the cost of a primary ice detection system, an advisory ice detection system, or activate the IPS’s when entering conditions conducive to airframe icing.

1 “T reatment of the Economic Value of a Statistical Life in Departme ntal Analysis ”, March 18, 2009 , U.S. Department of Transportation Memorandum. 2 Department of Labor, Bureau of Labor Statistics. Occupational Employment and Wages ,8

For section (a)(1), (a)(2), and (a)(3) of the final rule , the costs include: (1) Indirect Non - recurring Airplane Group Costs (2) Direct Operator Costs. To determine the indirect non - recurring costs, we requested and the IPHWG provided sy stem design, s ys tem certification, updating the AFM, flight tests and retrofit costs. These IPHWG provided indirect costs are shown in Appendix C1, C2 , and C3. To determine the direct costs to operators to implement sections (a) (1) , ( a) (2) , or ( a) (3) of the final rule, the anal ys is required distinguishing each airplane b y having either one of two ice detection systems installed, or having no ice detection sy stem installed. To satisfy the intent of section (a) (1) or ( a) (2) of the final rule, each of the airplane groups w ere analyzed to determine if they currently had: (1) a primary

ice detection sy stem (a)(1) , or **Does the Airplane have a Primary Ice**  **Detection System? (a)(1)**  **Does the Airplane have an Advisory Ice**  **Detection System and Visual**  **Cues? (a)(2)**  

### Yes **No No** 



### Yes

**Air plane is Compliant**  **Cost = $0.00 Airplane is Compliant**  **Cost = $0.00 Cost =**  **min[(a)(1),(a)(2), or a(3)]**  

# Exhibit 1 **Cost of (a)(1), (a)(2), or (a)(3) Compliance**9

(2) an advisory

ice detection system installed, along with visual cues (a)(2). If the airplane had either one of the tw o options, then the intent of section (a) (1) or ( a) (2) has been satisfied and operators of these airplanes will not incur additional compliance costs from this final rule . If an airplane does not have either one of the two options, then when the airplane is operating in conditions conducive to airframe icing, the operator must either install a primary or advisory ice detection sy stem or section (a)(3) mandate s that the ice protection system must be activated prior to and operated during all phases of flight except take - off and cruise (unless prohibited by

the AFM). The following sections will discuss the indirect non - recurring and direct costs associated with section (a)(1), (a)(2), and (a)(3) We provide cost estimates for section (a)(1), (a)(2), and (a) (3) and discuss why (a)(3) is th e low - cost alternative for the final rule. **III.4 Section (a)(1) and (a)(2)**  **- Indirect Non**  **- recurring Airplane Group Costs**  If the decision is made to install a primary or advisory

ice detection system, non recurring costs c onsist of the following: (1) Sy stem Design

– includes ice detector system architecture and integration, positioning, and updating the manufacturer’s AFM procedures ; (2) Sy stem Qualification/C ertification

– includes ice detector qualification, certification, and fl ight test ; and (3) Tasks associated with the retrofit

– includes service bulletin preparation, approval and a crew - training program. **III.5 Section**  **(a)(1) and (a)(2) –**  **Direct Operator Costs**  Direct operator costs are defined herein as:10 (1) The purchase of Primary or Advisory I ce Detection sy stem , (2) The installation of the Primary or Advisory

I ce Detection system , (3) Pilot Training costs , and (4) Updating the operator’s AFM. The IPHWG , operators and industry associations provided the FAA with the costs of purchasing and installing primary or advisory

ice detection systems for the airplanes affected by this final rule . 3 These costs are shown in Appendix C1 and C2 . **III.6 Section (a)(3)**  **- Indirect**  **Non -**  **recurring and Direct Operating**  **Costs** There are three non - recurring op erator costs associated with continuously operating the IPS during all phases of flight except take off and cruise. They are: (1) Updating the manufacturer’s AFM for each major airplane group, (2) Updating the operator ’ s AFM for each major airplane group , and (3) Fl ight tests. The non - recurring costs were distributed equally across each of the operator’s airplanes in each of the operator’s major airplane groups . These costs are shown in Appendix C3. Note the more airplanes in a major airplane group, the lower the non - recurring average costs are to the operators of those airplanes. The converse is also true. We believe operators will follow the timeframe listed in § 121.321 and incur these costs 24 months after the effective date of the final rule. Since (a)(3)(i) effectivel y will increase the usage of IPSs, then this final regulation will increase costs of maintenance and of replacement of the IPSs. In order to estimate the increased

3 The IPHWG provided costs in 2002$ and we escalated the costs to 20 10 $ based on inflation. To account for inflation, we used current dollar and real GDP figures for 2000 - 20 1 0 from the Bureau of Economic Analysis ( BEA) website.11

maintenance costs and the increased frequency of replacing the IP Ss, the FAA rev iewed the currentl y issued Airworthiness Directives ( AD s ) concerning activation of the IPS and how the AD s differed from this final rule. The AD s in Docket Number 99 -NM - 137 - AD through 99 - NM - 145 - AD, 99 - NM - 147 - AD through 99 - NM - 154 - AD, and AD 2001 - 06 - 18 require airplane operators of certain4 airplanes to activate the pneumatic wing and tail deicing boots at the first sign of ice accumulation. The final rule will require the operators to activate the pneumatic wing and tail deicing boots when visible moisture is at or below a static air temperature of + 5 degrees C or a total air temperature of + 10 degrees C . When the IPS is operated based on visible moisture and temperature , there might not be ice accumulating on the airframe. Thus, the final rule is more con servative than the current AD s issued because the IPSs will be activated even though ice may not be accreting on the airframe. The IP HWG provided data from one operator who clai ms that the increase d use of the IPS mandated b y the AD s in Docket Number 99 - NM - 137 - AD through 99 - NM - 145 - AD, 99 -NM 147 - AD through 99 -NM - 154 - AD, and AD 2001 - 06 - 18, w ould drop the average service life of a pneumatic deicing boot from 4 years to 2 - 2.5 years. F rom f urther consultations with industry associations and operators of affecte d airplanes , we discovered this final requirement will further drop the average service life of a pneumatic deicing boot to one ye ar. We averaged the IPHWG, industry associations and operators of affected airplanes provided cost estimate s to develop the cost basis for this final rule . The AD s added an additional $ 28 7 per month, per airplane in maintenance and replacement costs to operate the IPSs. F or airplanes subject to the AD s , the further increase of boot usage due to the final rule w il l add an addi tional $ 464 per month , per airplane and certification and initial operator costs of about12

$1 9 , 500 per airplane group or ty pe . The IPHWG , industry associations and operators of affected airplanes estimate the final rule w ill not need additional flight test s for airplanes subject to th es e AD s . Appendix C3 shows these costs. For airplanes which are not subject to the AD s and are operating the deicing boots based on flight crew observation of a specific thickness of ice, the increased deicing boot usage will add $ 751 per airplane, per month. These additional costs are shown in Appendix C3 and include boot maintenance, replacement and installation labor and are the onl y recurring costs estimated over the analysis period. Also, f or airplanes which are not subje ct to the AD s and are operating the deicing boots based on flight - crew observation of a specific thickness of ice , there will be $ 17,295 for s ys tem design procedures and $ 360,927 for flight tests . Those costs are estimated to be about $ 3 78,222 per airplan e group and are also shown in Appendix C3. Section (a)(3) will also require that e ach U.S. certificated operator provide training for pilots and copilots of airplane s to comply with procedures mandated b y the final rule. The FAA accepts the IPHWG’s estim ate of two hours of initial training per pilot or copilot , one hour to update the AFM, and ten pilots per airplane . At $ 104.99 per hour training costs, 5 the FAA estimates that the initial cost of training will be about $ 2,205 per affected airplane. The training costs estimated are one - time fees incurred in the first year the final rule becomes effective. **III. 7**  **Section (b) –**  **Airplane Flight Manual (AFM)** Section (b) of the final rule states that if the procedures in section (a)(3) are prohibited in the AFM, then compliance must be shown with the requirements of section (a)(1) or (a)(2). The

4 Note: not all airplanes affected by this final rule were subject to the icing AD’s. 5 Ice Protection Harmonization Working Group (IPHWG) of the Aviation Rulemaking Advisory Committee (ARAC) escalated to 2010$.13

FAA has found no case where the procedures in section (a)(3) are prohibited in the AFM for airplanes affected b y the final rule. Therefore, section (b) adds no cost s to the operators. **III. 8**  **Section (c), (d) and (e)** Costs for section (c), (d) and (e) of the final rule are embedded in the estimates for section s (a) and (b). **III. 9**  **Estimating the Number of Affected Airplanes** The cost estimates discussed above are per- airplane costs. To obtain a total cost estimate, these per airplane costs are multiplied by the number of airplanes; hence, the fleet of affected airplanes must be estimated. To estimate the number of affected airplanes , the FAA anal yz ed the current active fleet of airplanes, a forecast of airplanes affected b y the final rule entering the fleet, and a forecast of the retired affected airplanes exiting the fleet during the anal ys is period. A list of all U.S. operated civilian airplanes operating under 14 CFR Part 121 was generated b y the FAA Flight Standards Group. 6 We determined that all newly delivered part 121 airplanes will either have a primary or advisory ice detection system and therefore will be compliant with the final rule. Hence, we conclude d that future deliveries of new airplanes, affected b y this final rule , will be compliant and incur no costs. Each airplane group was matched with its current (as of May 2010 ) Maximum Take - Off Weight ( MTOW ) and average age through the use of the OAG FleetP C  database.

6 NVIS Air Operator Database ; May 201014

All airplanes with a certified MTOW greater than 60,000 pounds were eliminated, leaving 2, 1 3 6 airplanes in the active fleet to be subject to the final rule. Using industry

sources, the FAA determined which affected active airplanes had primary or advisory

icing detection sy stems. Table 1 details the number of affected part 121 turboprop and turbojet airplanes, their average age, and their ice detector equipage status.

The ATR 42, ATR 72, CRJ, DHC - 8 , Dornier 328, and all affected Embraer air planes are equipped with either a certificated primary or advisory

ice detection systems (IDS); hence, these airplanes are in compliance with either § 121.321(a)(1) or § 121.321(a)(2) and this final rule will impose no costs on the operators of these airplan es.15

We note all affected part 121 turbojet airplanes are already in compliance and hence will incur no costs from this final rule . The FAA used the FAA Statistical and Forecast Branch 7 for the part 121 regional turboprop forecast to estimate the number o f active and retired turboprop airplanes over the anal ys is interval. Since the FAA Statistical and Forecast Branch does not forecast turboprop airplanes b y equipment ty pe, f or the costs estimate, we retire the older active airplanes affected by the final rule first. When we estimated the costs for the NPRM we used the 2008 FAA fleet forecast. The 2008 FAA fleet forecast had an aggressive turboprop retirement forecast. For the final rule, we used the 2010 FAA Fleet Forecast. O ver the analy sis interval, the 2010 FAA retirement forecast i s flat for turboprops as opposed to the decline in the 2008 FAA fleet forecast . The impact of the flat 2010 retirement forecast is that more turboprops will be active over the anal ys is interval . More active turboprops r aises the costs of the final rule relative to the NPRM. Based on this approach, the C - 46, CV - 340/440, DHC - 6, and S A - 227 , and S D - 3 - 60 airplanes will be retired before the 2013 effective date of this final rule and hence incur no compliance costs. The remaining affected airplanes are the B - 1900 and Saab 340 . Since these airplanes do not have an IDS; they will have to comply with § 121.321(a) (1) , (a)(2) or (a)( 3 ) and incur the costs of either installing a primary or advisory

IDS or continuously

operating their IP S when operating in conditions conducive to icing. Using the costs discussed above and listed in Appendix C1, C2, and C3, we estimate the total nominal cost of making the B - 1900 and Saab 340 compliant to this final rule . We estimated the costs for §§ 121.321(a)(1) and (a)(2) b y adding the s ys tem design, qualification, certification and retrofit costs to the operator cost. We calculated the operator cost16

by taking the product of the number of active affected part 121 turboprop airplanes and the operator cost. We estimated th e cost for § 121.321(a)(3) , by first adding the non - recurring costs for the B - 1900, which was not subject to the AD s , to the non - recurring costs for the Saab 340, which was subject to the AD s . Since we estimate the final rule wil l not be promulgated until 20 1 1 , and has an effective date 24 months from the promulgation of the final rule, the non - recurring costs , for updated AFMs and flight testing will occur two years after the final rule is published . From ye ar one through 20 of the anal ys is interval, the recurring costs extend to operators of active B 1900 and Saab 340 turboprop airplanes . These recurring costs will decline over the analysis interval because of Saab 340 and B - 1 900 airplanes retiring. Table 4 shows the details o f the estimated nominal , three and seven percent present value costs for each section of the final rule.

7 APO - 110 - FAA Aerospace Forecast, 20 1 0 - 20 30 , Table 2617

**III. 10**  **Summary of Costs** Based on the IPHWG airplane compliance costs, the FAA estimates the cost s for § 121.321 (a) (1) - (3) will range between $ 1 1 . 8 million to $ 18.4 million on a nominal basis. The nominal value low est cost option is $1 1 . 8 million for § 121.321(a)(2), which requires operators to install an advisory

ice detection system and employ visual cues of the first sign of ice formation. Altho ugh the nominal value low est cost option is § 121.321(a)(2), the FAA believes that operators will choose § 121.321(a)(3) because this option does not require large up - front direct costs of designing and certificating an advisory ice detection s ys tem for turb oprops that will be over 20 years old by

the effective date of this final rule . In addition, our cost estimate of $12.718

million for § 121.321(a)(3) is for using deicing boots 12 months a year, which is an over- estimate because ice protection systems, such as deicing boots, are not used ye ar round. L astl y, on a present value basis, § 121.321(a)(3) is the low cost option. Therefore, we believe that § 121.321(a)(3) will be the preferred option to comply with this final rule. The seven percent present value cos t for § 121.321(a)(3) of this final rule over the anal ys is period is about $ 6.7 million. The three percent present value cost of this final rule over the anal ys is period is about $ 9.4 million . We estimate that the final rule’s non - recurring costs of certi ficating affected airplanes for the low cost option § 121.321(a)(3) are a pproximately $ 400,000 and about $ 12. 3 million for recurring operator costs and to provide training for pilots and copilots of airplane s involved with new procedures mandated b y the fin al rule. Appendix C 4 shows the details of the certification and operator costs , for each section, throughout the anal ys is period.19

**IV. THE BENEFITS ESTIMATE**  The FAA expects the final rule to generate potential safety benefits of about $ 36.6 million over the 20 - ye ar anal ys is interval , about $18.9 million at the seven percent present value rate, and about $ 27.1 million at the three percent present value rate. The se total benefits must be factored down , for certain airplanes, because of existing Airworthiness Directives (AD s ) . The industry I ce Protection Working Group (IPHWG) and the FAA assigned a 50 percent effectiveness rate for the final rule given existing AD s . Based on industry ’s judgment, and we received no comments on this value for the NPRM, we continue to use 50%. Under the current operating rules, it is the responsibility of the flight crew to decide whether icing conditions have been encountered. Neither the operation regulations nor the certification regulations require a means for the pilot in c ommand to identify that hazardous icing conditions have been encountered. An examination of the accident and incident history revealed that the flight crews must be provided with a clear means to know when to activate the Ice Protection Sy stem ( IPS ) . Thi s final rule will ensure timely activation of the IPS. Since 19 93 , 14 CFR Part 121 passenger - carrying air operators have had at least one accident which may

have been prevented if this rule had been in effect. The accident occurred in 1993 in Hibbing, MN. The airplane was a Jetstream BA - 3100 and while on approach collided with trees and terrain resulting in 18 fatalities, no injuries , and a destro ye d airplane. 8 Th is accident occurred in a small (under 60,000 pound MTOW) 14 CFR Part 121 airplane , which i s affected by

this final rule.

8 National Transportation Safety Board (NTSB) Accident Reports, FAA National Aviation Safety Data Analysis Center (NASDAC).20

In addition to this U.S. accident, there were 10 international icing related accidents that could have been prevented if this final rule was in effect internationall y. H owever, w e assign no quantitative benefits to these i cing - related accidents . Table 5 sh ows these international icing related accidents.

Additional i cing related accidents during the cruise, holding and landing phase of flight have also occurred in Greenland, Ital y, Kazakhstan, Russia, and Sweden. 9 We also found accidents and incidents that occurred under Part 135 operations. They are considered as relevant to this final part 121 rule because under today ’s regulations those Part 135 operations would be classified as Part 121. Now we discuss the component b enefit of an averted accident which form s the quantitative basis f

or future benefits. The benefit of avoiding an accident includes averted fatalities, injuries, aircraft replacement or repair, and accident investigation costs. In estimating benefit valu es, the FAA uses $6.0 million for an avoided fatality , $521,000 for a serious injury (assumed to be the average of a severe, serious, and moderate injury), and $12,000 for a minor injury . The

9 Ice Protection Harmonization Working Group (IPHWG) of the Aviation Rulemaking Advisory Committee (ARAC).21

additional associated medical and legal costs for a fatality are $265,400, for a serious injury (assumed to be the average of a severe, serious, and moderate injury) $93,267, and for a minor injury $5,000. The air carrier accident investigation cost for the NTSB is $ 1,931,800 and for an FAA accident investigation $ 681,700 . The NTSB accident investigation reports provided the number of fatalities and injuries. The FAA estimates the average value of avoiding an icing related accident, where the airplane is destro yed, to be about $ 11 9 . 9 million. 10

We believe this final rule c ould have prevented at least one historical accident and the 18 fatalities that occurred . Further, w e e xpect future accident s in conditions conducive to icing to also occur . Herein, the methodology is presented to substantiate the basis fo r increasing the value of preventing icing related accidents that could occur over the analysis interval in the absence of the final rule: 1. Based on the casualty losses from the 1993 Hibbing, MN Jetstream BA - 3100 accident , we calculate three separate accident and casualty rates. These accident and casualty rates were calculat ed b y dividing the total losses per category (fatality , investigation and accident) over the 1993 through 20 10 period b y the average number of part 121 air carrier airplanes operating in th e time period. 11 The results of this derivation are exhibited in Table 7 .

10 Economic Value s For FAA Investment and Regulatory Decisions, A Guide 11 U.S. Department of Transportation, Federal Aviation Administration, Office of Aviation Policy, Plans and Management Analysis, Statistical and Forecast Branch.22

2. The historical accident and casualty rates , calculated in step 1 were multiplied by the annual number of projected declining part 121 affected U.S. operated airplanes from 20 11 through 20 3 2 . 12 3. After totaling the estimated number of future accidents and casualties over the anal ys is period, w e used the values in Table 6 to determine the total potential benefits of the final rule. Table 7 shows these calculations. Appendix B1 sho ws the details of the benefit costs throughout the anal ys is period.

12 ibid23

In the absence of the final rule, based on past accident rates , w e expect approximately one accident will occur over the analysis period . Th is accident is expected to result in approx imately five fatalities. The accident - rate assumptions must account for the effects of re cent AD s against affected models because the FAA does not accept that this icing rule, b y itself, will prevent all future accidents. The AD s were issued to establis h an increased level of safety with respect to initiating activation of the IPS and providing cues to determine when large droplet icing conditions have been encountered. The benefits anal ys is considers accidents and incidents that occurred prior to the i ssuance of the AD s . In 1996 , AD s were issued for airplanes with unpowered controls and pneumatic de - icing boots. In 1999 a second series of AD s were issued for airplanes with pneumatic de - icing boots to activate the s ys tems at the first sign of ice accr etion. These two AD s accomplish much of the same objectives as this 14 CFR Part 121 final rule. A second set of AD s required the activation of the IPS at the first sign of ice accretion any where on the airplane or upon annunciation of an ice detection s ys tem. The system is to be operated on automatic mode if available or b y manually cycling to minimize ice accretions on the airframe. This directive accomplishes much of what final rule sections (a) and (b) are proposed to achieve. The main difference i s that the final rule will require a more conservative activation cue (temperature and visible moisture) and that the visual cues used in combination with an advisory

ice detection will require validation (or re - validation). Due to the similarity

of requirements, we realize that the AD s have accomplished a substantial portion of the safety increase attributed to the final rule within the benefits anal ys is. The IPHWG, with FAA concurrence, believes it is reasonable to assume that the AD s have24

already accompl ished 50 percent of the safety benefit attributed to the final rule in the anal ys is. This difference would indicate that the actual safety benefit of the final rule is on the order of 50 percent of the present values due to the effectiveness of the AD s . For the two affected airplanes, the AD s appl y to the Saab 340 and not the B - 1900. Therefore the benefits of preventing future accidents on Saab 340 airplanes have been reduced by 50 percent. Table 7 shows the benefits of preventing th is accident and th ese casualties are estimated at $36.6 million in nominal dollars . We proportioned the total and present value benefits from Table 7 b y calculating the percentage of Saab 340 and B - 1900 airplanes operating in 20 1 0 . We then add ed 100 percent of the B - 1900 portion of the total and present value benefits to 50 percent of the Saab 340 portion to account for the safety benefits from the AD s . Assuming that the actual safety benefit s of the final rule is on the order of 50 percent for the Saab 340 and 100 percent for the B - 1900, benefits of preventing this accident and these casualties are estimated at about $ 27.2 million in nominal dollars . Table 8 shows these adjusted benefits , including the AD s effective ratio for the Saab 340.

**V. BENEFIT**  **- COST SUMMARY**  In the absence of this final rule, it is highl y likely that future icing - related accidents will occur. This study expects at least one accident and five fatalities over the 20 - ye ar anal ys is interval could be prevented by the enactment of this final rule and AD s . The benefit of the final25

rule will be avoiding this anticipated accident. We accounted for the effects of recent AD s against affected models . The benefits of the final rule are estimated to be $ 2 2 . 1 million in nominal dollars over the anal ys is peri od. It is estimated that over the anal ys is period, cost of the final rule is about $ 1 2 .7 million in nominal dollars . This includes the cost of ice detection sy stems design, qualification, certification, crew training, equipment purchase and installation , and testing. Table 9 shows these results.

The estimated $ 2 2 .1 million benefit of this final rule exceeds the estimated $ 1 2. 7 million cost in nominal dollars . We note that for the total and three percent present value cases, the estimated benefits also exceed the estimated costs. Thus, accepting the IP HWG’s recommendations, the FAA concludes that the benefits of the final rule do justify the costs of this 14 CFR Part 121 final rule.

### Appendix C1 **Manufacture r**  **Non -**  **recurring and Direct Operator Cost s for Section (a)(1)** 27 

### Appendix C2 **Manufacture r**  **Non -**  **recurring and Direct Operator Costs for Section (a)(2)**28 

### Appendix C3 **Manufacture r**  **Non -**  **recurring and Direct Operator Costs for Section (a)(3)**29 

### Appendix C **4 Cost Summary** 30 

### Appendix B1 **Benefi t Summary**