CESSNA TWIN ICING AD---INITIAL REGULATORY FLEXIBILITY ANALYSIS

Daniel Leach

08-08-2012

Introduction and Purpose of This Analysis

The Regulatory Flexibility Act of 1980 (Public Law 96-354) (RFA) establishes “as a 

principle of regulatory issuance that agencies shall endeavor, consistent with the objectives of the 

rule and of applicable statutes, to fit regulatory and informational requirements to the scale of the 

businesses, organizations, and governmental jurisdictions subject to regulation.” To achieve this 

principle, the RFA requires agencies to solicit and consider flexible regulatory proposals and to 

explain the rationale for their actions to assure that such proposals are seriously considered.” The 

RFA covers a wide-range of small entities, including small businesses, not-for-profit 

organizations, and small governmental jurisdictions.

Agencies must perform a review to determine whether a rule will have a significant 

economic impact on a substantial number of small entities. If the agency determines that it will, 

the agency must prepare an initial regulatory flexibility analysis (IRFA) as described in the RFA.

Section 603(a) of the RFA requires that each initial regulatory flexibility analysis contain:

(1) a description of the reasons action by the agency is being considered;

(2) a succinct statement of the objectives of, and legal basis for, the proposed rule;

(3) a description of and, where feasible, an estimate of the number of small entities to which the 

proposed rule will apply;

(4) a description of the projected reporting, recordkeeping and other compliance requirements 

of the proposed rule, including an estimate of the classes of small entities which will be 

subject to the requirement and the type of professional skills necessary for preparation of 

the report or record; and

(5) to the extent practicable, an identification of all relevant Federal rules which may duplicate, 

overlap or conflict with the proposed rule.

(6) Each IRFA shall also contain a description of any significant alternatives to the proposed 

rule which accomplish the stated objectives of applicable statues and which minimize any 

significant economic impact of the proposed rule on small entities.
2

1. A Description of the Reasons Action by the Agency Is Being Considered

For the airplanes listed in Cessna Aircraft Company (Cessna) Service Bulletin MEB97-4, the

actions required by this proposed rule will prohibit flight into known icing conditions. An

investigation of the airplanes affected by the proposed rule showed 52 icing-related incidents and 

accidents over the last 30 years resulting in 36 fatalities. The non-fatal accidents have usually 

resulted in injuries and substantial aircraft damage. Although many of these airplanes are 

equipped with optional deicing boots and other deicing (or icing prevention) equipment, the 

manufacturer never intended that they should be flown into known icing.1 However, the original 

certification basis for these airplanes did not incorporate Amendment 7 (May 3, 1962) of CAR 3, 

requiring manufacturers to provide a placard specifying the types of operations and 

meteorological conditions (e.g. icing conditions) to which the operation of the aircraft is limited 

by the equipment installed (CAR 3 § 3.772). As a result, with operational deicing equipment 

these airplanes may be qualified to fly into known light or moderate icing condition under 14 

CFR § 135.227(c)(1)2and may even be allowed to fly into known icing conditions under 14 CFR 

Part 91.9.3In 1973 new Part 23 certification rules became effective. Some of the later production 

of the affected Cessna models added new and improved equipment in order to recertify under the 

new requirements. However, production under previous type certificates continued as late as 

1976.

2. Objectives of, and Legal Basis for, the Proposed Rule

The proposed rule would require owners or operators to install a placard prohibiting flight 

into known icing conditions. With the limited deicing equipment of the affected airplanes, flight 

into known icing conditions could result in unusual flight characteristics leading to loss of 

control with consequent accidents. The proposed rule would also require owners or operators to 

install a second placard that increases published speed on approach by 17 mph (15 knots) in case 

 

1

For example, one of the Model 310 manuals notes: “Since wing and horizontal stabilizer deicer boots alone do not 

provide adequate protection for the entire aircraft, known icing conditions should be avoided whenever possible.”

2

§ 135.227(c) allows flying into known icing conditions if “(1) The aircraft has functioning deicing or anti-icing 

equipment protecting each rotor blade, propeller, windshield, wing, stabilizing or control surface, and each airspeed, 

altimeter, rate of climb, or flight attitude instrument system; ...”

3

§ 91.9 states that “no person may operate a civil aircraft without complying with the operating limitations specified 

in the approved Airplane or Rotorcraft Flight Manual, markings, and placards....”
3

of an inadvertent encounter with icing. Many of the Cessna accidents were the result of high sink 

speeds, which may have been related to icing, resulting in hard landings. Failure to mandate an

increased published speed may result in continuing occurrences of this unusual flight 

characteristic with consequent accidents.

Title 49 of the U.S. Code specifies the FAA’s authority to issue rules on aviation safety. Subtitle I, 

section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes 

in more detail the scope of the FAA’s authority.

We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, 

section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting 

safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and 

procedures the Administrator finds necessary for safety in air commerce. This regulation is within the 

scope of that authority because it addresses an unsafe condition that is likely to exist or develop on the 

airplanes identified in this AD.

3. A Description of and an Estimate of the Number of Small Entities to which the 

Proposed Rule Will Apply

The airplanes affected by the AD are the 4206 U.S.-registered Cessna twin-engine airplanes

with certain serial numbers among Models 310, 320, 340, 401, 402, 411, 414, and 421 specified 

in Cessna Service Bulletin MEB97-4.4

To obtain information on small entities affected by the AD, we emailed a questionnaire 

directly to seven firms with the largest number of airplanes listed in Cessna Service Bulletin 

MEB97-4 and received responses from six of these firms—the Small Sample. Separately, the

Aircraft Owners and Pilots Association (AOPA) conducted an online survey and received 198 

responses from owners with affected airplanes. This sample was reduced to 104 entities—the

Large Sample--by eliminating 94 responses from individuals who used their airplanes for 

personal use only. 

Employment size in the Small Sample ranges from 6 to 48, with a median of 16.75. For the

Large Sample 84 out of 104 respondents reported employment size, ranging from 1 to 1000, with 

a median of 6. Since, as noted, personal use appears to account for about half of the airplanes 

 

4

http://www.faa.gov/licenses_certificates/aircraft_certification/aircraft_registry/releasable_aircraft_download/. 

February 24, 2012.
4

listed in Cessna Service Bulletin MEB97-4, we estimate the number of entity airplanes affected 

by the AD to be half of 1608, or 804.

5

As to type of operations, the Large Sample indicates only if the owner’s airplane(s) are for 

“Corporate” or “Charter” use. All of the firms in the Small Sample engage in Part 135 operations 

of one kind or another—on demand air charter, cargo and/or passenger, or scheduled freight. The 

Small Business Administration (SBA) classifies Part 135 operations into NAICS industries 

481111, Scheduled Passenger Air Transportation; 481112, Scheduled Freight Air Transportation, 

481211, Nonscheduled Passenger Air Transportation; and 481212, Nonscheduled Freight Air 

Transportation.

For all of these industries, the SBA maximum small business size is 1,500 employees. All of 

the entities in both samples are well below 1,500 employees. Accordingly, we conclude that the

proposed rule would affect a substantial number of small entities.

4. Reporting, Record Keeping, and Other Compliance Requirements of the Proposed Rule

Small entities will incur no new reporting and record-keeping requirements as a result of this 

rule. 

An Initial Regulatory Flexibility Analysis was not undertaken for the NPRM (76 FR 32105), 

June 3, 2011, as the FAA initially determined that the cost of the proposed rule was minimal, being 

just the cost of placard installation. However, as a result of comments to the NPRM docket, it 

became apparent to the FAA that there may be significant additional costs for the subset of the 

affected airplanes with optional deicing equipment. Several commenters to the NPRM docket argue 

that affected airplanes with deicing equipment can be safely operated in light or moderate icing 

conditions. They further argue that to be prohibited from doing so would severely restrict their 

operations and impose significant costs.

As a result of these comments, we surveyed Cessna Twin operators and independently estimated 

the cost imposed on operators by the mandated prohibition on flight into known icing. We 

approximated this cost by estimating the cost to operators of substituting airplanes certified for flight 

into known icing for their current airplanes. In response to a request from the FAA, Cessna 

undertook a sample survey and estimated that 38.23% of the airplanes listed in Cessna Service 

Bulletin MEB97-4 were equipped with deicing boots. Most of these airplanes also have deicing 

 

5 This figure is an underestimate to the extent that airplanes for business use are more likely to have deicing 

equipment than airplanes for personal use.
5

propellers, making them eligible for flight into known icing under Part 135.227 and, in any case, 

these airplanes may be eligible for flight into known icing under Part 91.9. Applying that percentage 

to our airplane count of 4206, we obtain an estimate of 1608 AD-affected airplanes whose operators 

would be affected by the prohibition on flight into known icing.

Cost of Proposed Rule per Airplane

All 4206 U.S.-registered Cessna twin-engine airplanes will incur at least the minimal cost of 

the required placarding. As already noted above, however, the AD will also prohibit operators of 

an estimated 1608 of the affected airplanes from flying into known icing conditions. Many

respondents estimate that they will incur significant costs as a result. As sample information

varies widely in quality, however, we use below an independent standardized approach to 

estimating the cost impact of this prohibition.

We approximated this cost by estimating the cost to operators of substituting airplanes 

certified for flight into known icing for their current airplanes. Although this may be a somewhat 

conservative approach, it allows us to estimate operator cost using just data on airplane values 

and a straightforward method. The closest available substitutes for the affected airplanes are 

similar Cessna Twins certified for flight into known icing, many in the same series and a few

even of the same model and year. Substitute airplanes, however, will generally be newer and 

more expensive than the AD affected airplanes.

In Table 1 below we show the distribution by model series of the AD affected airplanes, and 

in Table 2 we show the distribution by model of substitute airplanes certified for flight into 

known icing. In Table 1 the Mid-Production Model is the model of the median airplane in a 

chronological list of all the registered airplanes in the Model Series. In both tables the MidProduction Year is the year in which the median airplane was produced. Airplane Value is the

base retail valuation for the median airplane from a sample of airplane valuations from the 

AOPA website. It is used here as a measure of the average airplane value for the model series in 

Table 1 and for the model in Table 2.
6

Table 1. Distribution by Model Series of Airplanes Affected by the

Cessna Twin Icing AD

Model 

Series Models

Pdn 

Years

No. 

of 

APs 

MidPdn

Model

MidPdn

Year AP Value 

310 310, 310A-R 1955-81 2377 310J 1965 $ 44,000 

320 320, 320A-F 1962-68 302 320C 1965 $ 38,000 

340 340, 340A 1972-76 308 340 1974 $ 123,000 

401 401, 401A-B 1967-72 186 401A 1969 $ 71,000 

402 402, 402A-B 1967-74 199 402B 1972 $ 74,000 

411 411, 411A 1965-68 142 411 1965 $ 39,000 

414 414 1970-74 214 414 1972 $ 128,000 

421 421, 421A-B 1967-74 478 421B 1971 $ 115,000 

4206 1967.2 $ 64,142

Weighted Averages

Notes: The “Mid-Pdn Model” is the model of the median airplane in a chronological list of

all the registered airplanes in the Model Series. The “Mid-Pdn Year” is the year in which the

median airplane was produced. “AP Value” is the base retail valuation for the median airplane

from the Airplane Owners and Operators (AOPA) website, retrieved 03-26-12 to 04-02-12.

Table 2. Distribution by Model of Substitute

 APs Certified for Flight into Known Icing

Model

Pdn 

Years

No. of 

APs 

Mid-Pdn

Year AP Value 

310R 1976-81 274 1978 $ 110,000 

340A 1976-84 549 1979 $ 189,000 

402B 1974-78 105 1976 $ 90,000 

402C 1977-85 189 1980 $ 175,000 

414 1974-77 120 1976 $ 165,000 

414A 1977-85 414 1979 $ 270,000 

421B 1974-75 105 1975 $ 155,000 

421C 1975-85 616 1978 $ 255,000 

2372 1978.2 $ 202,935 

Weighted Averages

The tables show considerable variation in airplane value by model type. Not surprisingly, 

there is also considerable variation in airplane value over time as shown by the much lower 

weighted average value of $64,142 for the older AD airplanes (weighted average year of 1967) 

compared to the $202,935 weighted average value for the newer substitute airplanes (weighted 

average year of 1978). So an operator of a 310 model series AD airplane with a low average 

value of $44,000 looking for a substitute airplane would likely prefer, if available, a 310R with 
7

an average price of $110,000 or perhaps a 402B with an average value of $90,000, The owner of 

a 414 model series AD airplane with an average value of $128,000 would likely prefer, if 

available, to stay with the same model at an average substitute airplane price of $165,000. The

owner of a 1971 421B with a value of $115,000 would likely prefer a substitute 1974-1975 421B 

with an average price of $155,000, but might have to opt for a 421C, with a much higher average 

price of $255,000. And this is the case overall. Overall, airplanes in the Table 2 group substitute 

for the AD affected airplanes in Table 1. Accordingly, in order to continue to fly into known 

icing, operators will have to substitute airplanes with an average price of about $200,000 for 

their currently owned airplanes with an average value of about $64,000.

We estimate the cost per airplane of the proposed rule as the 10-year amortized cost of 

substituting a Cessna Twin certified for flight into known icing for a Cessna Twin not certified 

for flight into known icing. We limit our cost estimate to a 10-year period in order to greatly

simplify the analysis. We can measure the 10-year capital cost of an airplane (or any asset) by

estimating the decline in its value over the 10-year period. Substitute airplanes are more

expensive, have a higher capital cost, and will decline more in value than less expensive affected 

airplanes. The net cost of the rule per affected airplane will be the net decline in value incurred 

by the operator substituting the newer, more expensive, airplane for the older, less expensive

affected airplanes.

We approximate the decline in airplane value over time by the cross-sectional variation in 

value as estimated by a regression of airplane value on airplane age using our sample of 84 

AOPA airplane values (see Appendix). The sample covers the entire range of production years 

for each AD model and each substitute model. A double log transformation, in which the log of 

airplane value is regressed on the log of age, significantly improved the fit over an 

untransformed linear model. Dummy variables for the 320, 340, 401, 402, 411, 414, and 421 

model series were included in the regression equation to control for value differences by model 

series. The regression results are presented in Table 3 below:
8

Table 3. Regression of Airplane Value on

Airplane Age Using a Double Log Model

Coeffs

Std 

Error t Stat

Intercept 22.042 0.290 76.1

LnAge -2.943 0.077 -38.2

320s -0.125 0.044 -2.9

340s 0.381 0.043 8.8

401s 0.217 0.046 4.8

402s 0.011 0.035 0.3

411s -0.170 0.054 -3.2

414s 0.596 0.042 14.1

421s 0.620 0.036 17.1

R

2

0.981

Adj. R20.979

Std 

Error 0.099

Obs 84

Note: Airplane Value is basic retail valuation from the AOPA website.

The R

2

= 0.98 shows that the double log model provides a very good fit indeed. The t-statistic of 

38.2 in absolute value for the coefficient on the variable of interest, LnAge, shows the coefficient 

to be overwhelmingly significant. The negative value of the coefficient shows the standard 

negative relationship between age and airplane value.6Since the model is a double log 

 

6 A plot of airplane age against airplane value using the estimated regression results shows that as age increases, 

value falls rapidly up to about age 40, after which the relationship quickly flattens and value falls much less rapidly 

as age increases.
9

transformation, the coefficient measures a constant elasticity relationship between airplane age 

and airplane value, viz. the coefficient measures the elasticity of airplane value with respect to 

airplane age, or the age elasticity of airplane value. We use this feature of the double log model 

to estimate the 10-year decline in airplane valuation over time. The results of that estimation are 

shown in Table 4 below.

 
Table 4. 10-Year Cost of Substituting Icing Compliant Airplanes for AD Affected Airplanes

Substitute Airplanes Certified for Flight Into Known Icing

Production Year 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968

Airplane Age 34 35 36 37 38 39 40 41 42 43 44

Airplane Value $202,935 $185,871 $170,677 $157,102 $144,935 $133,998 $124,140 $115,229 $107,155 $99,822 $93,145

Change in Value -$17,063 -$15,194 -$13,575 -$12,167 -$10,937 -$9,859 -$8,910 -$8,074 -$7,334 -$6,676

AD Affected Airplanes

Production Year 1967 1966 1965 1964 1963 1962 1961 1960 1959 1958 1957

Airplane Age 45 46 47 48 49 50 51 52 53 54 55

Airplane Value $64,142 $60,038 $56,279 $52,828 $49,656 $46,733 $44,036 $41,544 $39,237 $37,099 $35,114

Change in Value -$4,104 -$3,759 -$3,450 -$3,173 -$2,923 -$2,697 -$2,492 -$2,307 -$2,138 -$1,985

Net Change $12,960 $11,091 $9,816 $8,716 $7,764 $6,936 $6,214 $5,582 $5,027 $4,538

 Present Value Change $12,112 $9,687 $8,013 $6,650 $5,535 $4,622 $3,870 $3,249 $2,734 $2,307

Total Present Value Cost $60,277

Annualized Cost $8,582

Notes: 1. Calculations may be off by one or more units owing to rounding error.

2. A 7% return on capital is recommended by the Office of Management & Budget. See OMB, Circular A-94, “Guidelines and Discount Rates for 

Benefit-Cost Analysis of Federal Programs”, October, 29, 1992, p. 8 (www.whitehouse.gov/omb/circulars/index.html).
In Table 4 we simultaneously estimate and amortize the 10-year decline in average airplane 

value for both the AD affected airplanes and their substitutes. For the substitute airplanes we 

start with the average airplane value of $202,935 from Table 2 and calculate the annual decline 

in value of the average airplane for ten years from the average year of 1978, or age 34. Since the 

estimated coefficient of -2.943 for Ln(Age) measures a constant elasticity relationship between 

airplane age and value, the one-year percentage change in value = -2.943 x the percentage

change in age, so the Change in Value = Airplane Value x -2.943 x the percentage change in age. 

For 1978 the calculation is then $202,935 x -2.943 x (1/35) = -$17,063.7The estimate of Change 

in Value results in an average Airplane Value estimate of $185,871 for 1977. The value estimate 

for 1977 is then used to generate the next estimate of annual decline in value, etc. until the entire 

10 years of changes are estimated. We repeat the process for the AD affected airplanes, starting 

with average Airplane Value of $64,142 and average year of 1967, or age 45, from Table 1. We 

then calculate the Net Change series as the difference between the substitute airplane Change in 

Value series and the affected airplane Change in Value series. Finally, we calculate the Present 

Value Change series by discounting the Net Change series by a discount rate of 7%.8Summing 

this series yields our estimate per airplane of the present value cost of the proposed rule, 

$60,277. The annualized cost can then be estimated to be $8,582.

Our estimate of $60,277 per airplane may seem large in comparison to an average affected 

airplane value of $64,142. The per affected airplane metric is a natural one when estimating the 

cost of a rule to an affected airplane. In this case the perspective of the per affected airplane 

metric is a poor one because we are substituting a different airplane for the AD affected airplane. 

The $60,277 estimates the cost to the operator of flying into known icing conditions. Without

this proposed rule, the operator can fly into known icing using an airplane with an average price 

of $64, 142. With the proposed rule, in order to do the same thing, the operator must fly a much 

newer and much more expensive airplane.

 

7 To measure the percentage, or proportionate, change in age in this calculation, we use 1/35 rather than 1/34 in 

order to treat the elasticity estimate as an arc elasticity, somewhat increasing the accuracy of our calculation.

8 A 7% return on capital is recommended by the Office of Management & Budget. See OMB, Circular A-94, 

“Guidelines and Discount Rates for Benefit-Cost Analysis of Federal Programs”, October, 29, 1992, p. 8 

(www.whitehouse.gov/omb/circulars/index.html).
12

Economic Impact on Small Entities

Our survey results indicate that almost all of the respondents were the owners of just one affected 

airplane. Of the 54 respondents reporting business receipts, 16 reported business receipts of 

$400,000 or less. For these respondents the annualized cost of the proposed rule implies an 

annual economic impact ranging from 2.1% to 19.1% of business receipts. We therefore 

conclude that this proposed rule will have a significant impact on a substantial number of firms.

5. Duplicative, Overlapping or Conflicting Federal Rules

The FAA is unaware of any Federal rules that duplicate, overlap, or conflict with this

proposed rule.

6. Significant Alternatives to the Proposed Rule

Owing to the existing unsafe conditions, however, there is no feasible significant alternative 

to prohibiting the affected airplanes from flying into known icing conditions. And there is no 

significant alternative to mandating an increase in published speed on approach.
13

Appendix—Basic Airplane Valuations for Cessna Twin Airplanes

AOPA 

Group Model Year Value 

Model 

Pdn Yrs

Affected 

by AD?

Model/Year Ser. 

Nos.

310 B-Q 310 1955 $ 29,000 1955-57 Yes 35000-35225

310 B-Q 310 1956 $ 30,000 1955-57 Yes 35226-

310 B-Q 310B 1958 $ 31,000 1958 Yes 35771-

310 B-Q 310C 1959 $ 32,000 1959 Yes 35772-39031

310 B-Q 310D 1960 $ 34,000 1960 Yes 39032-39299

310 B-Q 310F 1961 $ 36,000 1961 Yes 3100001-156

310 B-Q 310G 1962 $ 38,000 1962 Yes 310G0001-156

310 B-Q 310H 1963 $ 42,000 1963 Yes 310H001-148

310 B-Q 310J 1965 $ 44,000 1965 Yes 310J0001-200

310 B-Q 310K 1966 $ 47,000 1966 Yes 310K0001-245

310 B-Q 310N 1968 $ 53,000 1968 Yes 310N0001-198

310 B-Q 310Q 1970 $ 63,000 1970-74 Yes 310Q0001-130

310 B-Q 310Q 1972 $ 71,000 1970-74 Yes 310Q0401-545

310 B-Q 310Q 1973 $ 77,000 1970-74 Yes 310Q0601-845

310 B-Q 310Q 1974 $ 85,000 1970-74 Yes 310Q0901-1160

310 R 310R 1975 $ 95,000 1975-76 Yes 310R0001-330

310 R 310R 1976 $100,000 1975-76 Yes 310R0501-735

310 R 310R 1977 $105,000 1976-81 No 310R0801-1004

310 R 310R 1978 $110,000 1976-81 No 310R1201-1434

310 R 310R 1979 $115,000 1976-81 No 310R1501-1690

310 R 310R 1980 $125,000 1976-81 No 310R1801-1899

310 R 310R 1981 $135,000 1976-81 No 310R2101-2140

320 A-F 320 1962 $ 31,000 1962 Yes 3200001-110

320 A-F 320A 1963 $ 33,000 1963 Yes 320A0001-047

320 A-F 320B 1964 $ 36,000 1964 Yes 320B0001-062

320 A-F 320C 1965 $ 38,000 1965 Yes 320C0001-073

320 A-F 320D 1966 $ 43,000 1966 Yes 320D0001-130

320 A-F 320E 1967 $ 48,000 1967 Yes 320E0001-110

320 A-F 320F 1968 $ 54,000 1968 Yes 320F0001-045

340 A 340 1972 $115,000 1972-75 Yes 3400001-115

340 A 340 1973 $118,000 1972-75 Yes 3400151-260

340 A 340 1974 $123,000 1972-75 Yes 3400301-370

340 A 340 1975 $130,000 1972-75 Yes 3400501-555

340 A 340A 1976 $160,000 1976 Yes 340A0001-125

340 A 340A 1979 $189,000 1976-84 No 340A0601-801

340 A 340A 1980 $205,000 1976-84 No 340A0901-1045

340 A 340A 1984 $240,000 1976-84 No 340A1801-17
14

Appendix—continued

AOPA 

Group Model Year Value 

Model 

Pdn Yrs

Affected 

by AD?

Model/Year Ser. 

Nos.

401 A/B 401 1967 $ 64,000 1967-68 Yes 4010001-

401 A/B 401A 1968 $ 66,000 1967-68 Yes -322

401 A/B 401A 1969 $ 71,000 1969 Yes 401A0001-132

401 A/B 401B 1970 $ 82,000 1970-72 Yes 401B0001-

401 A/B 401B 1971 $ 84,000 1970-72 Yes 401B0201-121

401 A/B 401B 1972 $ 87,000 1970-72 Yes 401B0201-221

402 A/B 402 1967 $ 50,000 1967-68 Yes 4020001-

402 A/B 402 1968 $ 53,000 1967-68 Yes -322

402 A/B 402A 1969 $ 56,000 1969 Yes 402A0001-129

402 A/B 402B 1970 $ 69,000 1970-74 Yes 402B0001-

402 A/B 402B 1971 $ 71,000 1970-74 Yes -122

402 A/B 402B 1972 $ 74,000 1970-74 Yes 402B0201-249

402 A/B 402B 1973 $ 77,000 1970-74 Yes 402B0301-455

402 A/B 402B 1974 $ 81,000 1970-74 Yes 401B0501-640

402 A/B 402B 1975 $ 85,000 1974-78 No 402B0801-935

402 A/B 402B 1976 $ 90,000 1974-78 No 402B1001-1100

402 A/B 402B 1977 $ 95,000 1974-78 No 402B1201-250

402 A/B 402B 1978 $102,000 1974-78 No 402B1301-84

402 C 402C 1979 $165,000 1979-85 No 402C0001-125

402 C 402C 1981 $185,000 1979-85 No 402C0401-528

402 C 402C 1985 $245,000 1979-85 No 402C0808-1020

411 A 411 1965 $ 39,000 1965-66 Yes 4110001-

411 A 411 1966 $ 40,000 1965-66 Yes -250

411 A 411A 1967 $ 43,000 1967-68 Yes 4110251-

411 A 411A 1968 $ 45,000 1965-66 Yes -300

414/ A 414 1970 $120,000 1970-74 Yes 4140001-099

414/ A 414 1972 $128,000 1970-74 Yes 410251-280

414/ A 414 1974 $140,000 1970-74 Yes 4140451-550

414/ A 414 1975 $145,000 1974-77 No 4140601-655

414/ A 414 1976 $165,000 1974-77 No 4140801-855

414/ A 414A 1979 $270,000 1977-85 No 414A0201-340

414/ A 414A 1980 $290,000 1977-85 No 414A0401-535

414/ A 414A 1982 $330,000 1977-85 No 414A0801-858

414/ A 414A 1985 $370,000 1977-85 No 414A1007-212
15

Appendix—continued

AOPA 

Group Model Year Value 

Model 

Pdn Yrs

Affected 

by AD?

Model/Year Ser. 

Nos.

421 A/B 421 1967 $ 87,000 1967-68 Yes 4210001-

421 A/B 421A 1969 $ 92,000 1969 Yes 421A0001-158

421 A/B 421B 1970 $113,000 1969-74 Yes 421B0001-056

421 A/B 421B 1971 $115,000 1970-74 Yes 421B0101-147

421 A/B 421B 1972 $118,000 1969-74 Yes 421B0201-275

421 A/B 421B 1973 $125,000 1969-74 Yes 421B0301-486

421 A/B 421B 1974 $140,000 1969-74 Yes 421B0501-665

421 A/B 421B 1975 $155,000 1974-75 No 21B0801-970

421 C 421C 1976 $220,000 1975-85 No 421C0001-171

421 C 421C 1978 $255,000 1975-85 No 421C0401-525

421 C 421C 1980 $350,000 1975-85 No 421C0801-910

421 C 421C 1982 $370,000 1975-85 No 421C1201-257

421 C 421C 1985 $430,000 1975-85 No 421C1801-807

Source: AOPA website. Retrieved 03-26-12 to 04-02-12.