              OFFICE OF CHEMICAL SAFETY
AND POLLUTION PREVENTION
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            WASHINGTON, D.C.  20460
              OFFICE OF CHEMICAL SAFETY
AND POLLUTION PREVENTION
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            WASHINGTON, D.C.  20460

                                 June 25, 2014
                                                                PC Code: 121001
MEMORANDUM	DP Barcode: 418281

SUBJECT:	Sethoxydim: Drinking Water Exposure Assessment for IR-4 Petition on Fescue, Oilseeds, Fruits, and Vegetables

FROM:		James Lin, Environmental Engineer
            ERB2/EFED (7507P)

REVIEWED BY:  	Greg Orrick, Environmental Scientist
            	ERB2/EFED (7507P)

THROUGH:		Brian Anderson, Chief
            ERB2/EFED (7507P)

TO:		Sydney Jackson, Risk Manager
			Barbara Madden, Team Leader
			RIMUERB/RD (7505P)

			James Parker, Risk Manager
			Neil Anderson, Branch Chief
			RMIB1/PRD (7508P)

This assessment provides estimated drinking water concentrations (EDWC) of sethoxydim in surface water and in ground water in support of human health risk assessment for IR-4 petitions.  Screening EDWCs (Table 1) of sethoxydim were generated with the Surface Water Concentration Calculator (SWCC) and the Provisional Cranberry Model for surface water and with the Pesticide Root Zone Model for Ground Water (PRZM-GW) for ground water.  Modeled application rates represent the maximum use patterns of proposed end-use labels and current registered labels.  Remaining model input parameters were chosen according to current guidance (USEPA, 2009).  EDWCs reflect exposure to sethoxydim residues of concern in drinking water, which include the parent compound and eight degradates of concern (DP 246356).  If the screening EDWCs listed in this memo result in dietary risk exceedances, contact James Lin<PHONE_NUMBER>) of Environmental Risk Branch II (7507P) to request a refined drinking water exposure assessment.

Table 1.  Maximum Screening Drinking Water Exposure Estimates for Proposed Sethoxydim Uses (Based on Sethoxydim Residues of Concern)*
Source (Model)
Use (Maximum Rate)
                             Peak Exposure (μg/L)
                         Annual Mean Exposure (μg/L)
Surface water (SWCC)
                            4 apps @ 0.47 lb ai/A
                             w/ a 14-day interval
                                     65.3
                                      6.6
Ground water (PRZM-GW)

                                     0.565
                                     0.511
Surface water (Provisional Cranberry Model)
                  2 apps @ 0.47 lb ai/A w/ a 14-day interval
                                     79.6
                                     13.9
[*]Maximum values in bold.

	The Environmental Fate and Effects Division (EFED) has produced several drinking water assessments for sethoxydim, such as the following reports:

   1. D239881, D239882, D239884, D238951 - Drinking Water Assessment for Sethoxydim for the Current Uses and for Proposed IR-4 Uses on Leafy Vegetables (excluding Brassica), Root and Tuber Crops (excluding Radish), Artichoke, and Caneberries.

   2. D257560, D257310 - Drinking Water Assessment and Ecological Risk Summary for Sethoxydim for the Maximum Use Crop (Citrus) and the Proposed IR-4 Uses on Pistachio and Safflower.

   3. D312559 - Sethoxydim Drinking Water Assessment (Tier 1) for Reregistration Eligibility Decision.

   4. D313456, D314420 - Drinking Water Assessment for Sethoxydim: Proposed Uses on Buckwheat, Okra, Borage, Dill, Root Vegetables, and Turnip Greens.

      Due to recent updated modeling approaches, EFED is required to use new tools: the Surface Water Concentration Calculator (SWCC) for surface water and the Pesticide Root Zone Model for Ground Water (PRZM-GW) for ground water.  In addition to these two new modeling tools, this drinking water exposure assessment also uses the provisional cranberry modeling tool.

USE INFORMATION

	Sethoxydim is a broad-spectrum, postemergence herbicide for selective control of annual and perennial grass weeds.  It is belongs to the cyclohexenone-class herbicide.  The end use product is labelled as Poast(R) herbicide, which is formulated as an emulsifiable concentrate (EC) containing 1.5 pounds of active ingredient per gallon.  This IR-4 petition expands the proposed uses to include:

   1. New uses, R190, on fescue, Bushberry Subgroup 13-07B, Low Growing Berry Subgroup 13-07H, Small Fruit Vine Climbing Subgroup 13-07F, Rapeseed Subgroup 20A, Sunflower Subgroup 20B (except safflower), and Cottonseed Subgroup 20C.

   2. Crop group/subgroup additions, R175, for Citrus Fruit Group 10-10, Pome Fruit Group 11-10, Caneberry Subgroup 13-07A, Bulb Vegetable Group 3-07, and Fruiting Vegetable Group 8-10.

	For screening purposes, two use sites are considered for the drinking water assessment.  The first one is based on the highest label use rate among all uses.  The highest label use rate is for citrus fruit group. The maximum single application rate is 2.5 pt/A (0.47 lb ai/A).  The maximum seasonal rate is 10.0 pt/A (1.88 lb ai/A) with a 14-day retreatment interval.  The second one is based on cranberry use, which has a PHI (pre harvest interval) of 30 days.  The single application rate is same as the citrus rate.  The maximum seasonal rate is only 50% of the citrus use rate.

FATE AND TRANSPORT CHARACTERIZATION

      Transport and Mobility

      Sethoxydim is a highly soluble compound (4700 mg/L in pH 7 water) with a low octanol/water partition coefficient (Kow is 45.1).  The calculated bioconcentration factors (BCF) for sethoxydim and total residues were 7X, 25X, and 21X for edible, nonedible, and whole fish, respectively.  Depuration was fast, with a half-life of 3.6 days.  For these reasons, bioaccumulation is not likely to occur.  Also, due to its low vapor pressure (1.6x10[-7] mm Hg) and Henry's Law Constant (1.47x10[-11] atm-m3/mol), sethoxydim is not expected to be volatile under field conditions and from water.

      Based on batch equilibrium experiments, sethoxydim  and its transformation products, M2-SO2, M-SO, M-SO2, and M2-SO, were determined to be mobile to very mobile in sterile (autoclaved) sand, sandy loam, sandy clay loam, silt loam, and clay loam soils.  Freundlich Kd values were <1.00 for sethoxydim and its transformation products M-SO and M-SO2.  The Freundlich Kd values for M2-SO and M2-SO2 ranged from 0.06 to 9.12. The only unsterilized soils were used on M2-SO2, for the reason that M2-SO2 is thought to be the most stable among test compounds and it is the terminal degradate. The Freundlich Kd values of M2-SO2 with non-sterilized soil are 0.12, 2.89, 0.78, 5.64, and 9.42, respectively for sand, sandy loam, sandy clay loam, silt loam, and clay loam.

            Degradation

      Sethoxydim hydrolyzes at moderately rapid rates at low pH's, but is more stable at high pH's.  The calculated half-lives are 8.7, 155, and 284 days in pH 5, 7, and 9 solutions, respectively.  The major observed hydrolysis transformation product is M2-S or 6-(2-(ethylthio)propyl)-4-oxo-2-propyl-4,5,6,7-tetrahydrobenzoxazole.  In contrast, evaluation of the data of sethoxydim total residues shows that they remain stable at all three pHs tested.

      Sethoxydim and sethoxydim total residues degrade photolytically in both water and soil.  In pH 8.7 buffered water, the calculated photolysis half-life of sethoxydim is 5.23 days, and the major transformation product is M1-S or 2-(1-aminobutylidene)-5-(2-(ethylthio)-propyl)-cyclohex-1,3-dione.  In sandy loam soil irradiated with a xenon light source, the half-life of sethoxydim is approximately 1 hour, and the major transformation product is M-SO or 2-(1-ethoxyiminobutyl)-5-(2-(ethylsulfinyl)propyl)-3-hydroxycyclohex-2-enone.  Sethoxydim total residues photodegrade slower than parent sethoxydim in soil and water.  Using a linear regression analysis, EFED calculated a half-life of 19.8 days for the photolysis in water of sethoxydim total residues and a half-life of 20 hours in soil.

      Under aerobic conditions, parent sethoxydim transformed with short half-lives (<1 day) both in soil and aquatic environments.  It degraded with a half-life of less than one day in sandy loam and sandy clay loam soils.  The major transformation product at 2 months was M-SO, and after 12 months the major product was CO2.  Using aerobic clay loam soil:water and aerobic clay soil:water systems, it was determined that, under aerobic aquatic conditions, sethoxydim transformed with a half-life of <1 day.  After 28 days, the major transformation products were CO2, M-SO, M2-S, and M-SO2.  In contrast to parent sethoxydim, sethoxydim total residues were more persistent.  The observed half-life was 1 month for sethoxydim total residues in the aerobic sandy loam study, and 7 days in the aerobic sandy clay loam study.  In an aerobic clay loam soil:water system, the calculated half-life for sethoxydim total residues was 38.1 days, while in an aerobic clay soil:water system the half-life was 32.9 days.

      Under anaerobic conditions, parent sethoxydim is even more persistent than under aerobic conditions.  It transformed with half-lives of 11 to >60 days under anaerobic soil conditions and 25-39 days in anaerobic aquatic metabolism studies.  M-SO was the major transformation product in both studies.  It was observed that M2-S, which was a major transformation product in the hydrolysis study, was only a minor transformation product in the anaerobic aquatic metabolism study.  Sethoxydim total residues were more persistent than parent sethoxydim in the anaerobic studies.  A half-life of 91.6 days was observed in the anaerobic soil metabolism study, while half-lives of 132-187 days were observed in the anaerobic aquatic metabolism study.

      Residues of Concern

      The proposed degradation scheme of the parent and eight degradates has been discussed in an earlier memo (DP 312559).  The Metabolism Assessment and Review Committee (MARC) of the Health Effects Division (DP 246356) states that all degradates are to be included.  Because of the short metabolism half-lives of parent sethoxydim (< 1 day), the EDWCs represent total residues, including sethoxydim, M-SO, M-SO2, M1-S, M1-SO, M1-SO2, M2-S, M2-SO, and M2-SO2.  The proposed scheme of the transformation of sethoxydim and the eight metabolites is presented in Attachment 1.

      Drinking Water Exposure Assessment

      Drinking water exposure to the residues of concern is estimated using available chemical properties and environmental fate data.  A total residues of concern (TRC) approach was used because degradation studies were not performed on the specific degradates of concern.  Table 2 lists the environmental fate exposure modeling inputs of the sethoxydim TRC.   These parameters reflect regression of the total residues at each interval of the degradation studies.  Chemical properties of the parent compound were used to represent those of the residues of concern due to the lack of data on the degradates.  The mean soil adsorption coefficient for M2-SO2 was used to represent the residues of concern because this compound was thought to be the most prominent terminal degradate.  For the batch equilibrium study (MRID 41475212), the parent and 4 degradates (M-SO, M-SO2, M2-SO, and M2-SO2) were studied separately.  Due to the possible short half-life values of the parent and degradates, the batch equilibrium experiments were tested using sterile (autoclaved) soils.  The terminal degradate (M2-SO2) was thought to be most stable, so additionally it was also tested using non-sterile soil.  The results indicate that M2-SO2 is very mobile in sand, sandy loam, sandy clay loam, and silt loam and to be mobile in clay loam.  Freundlich Kd values were 0.12 for the sand soil, 0.78 for the sandy clay loam soil, 2.89 for the sandy loam soil, 5.64 for the silt loam soil, and 9.42 for the clay loam soil.  Adsorption increased as the CEC values of the soils increased.

Table 2.  Chemical Model Inputs for Sethoxydim Total Residues of Concern
Parameter
Value
Source
Molecular Weight (g/mol)
327.48
C17H29NO3S
Water Solubility (mg/L)
4700
EFED one-liner
Vapor Pressure (torr)
1.6 x 10[-7]
EFED one-liner
Hydrolysis half-life (day) (25 [o]C)
Stable (pH 5, 7, 9)
MRID 41475207
Aqueous photolysis half-life (day)
(25 [o]C)
19.8 (total residue)
MRID 41475208
Aerobic soil metabolism half-life (day) (25 [o]C)
54 (upper 90[th] percentile on two values of 30 days and 7 days for total residues)
MRID 41475210
Aerobic aquatic metabolism half-life (day) (25 [o]C)
44 (upper 90th percentile on two values of 38.1 days and 32.9 days for total residues)
MRID 42165604
Anaerobic aquatic metabolism half-life (day) (25 °C)
244 (upper 90th percentile on two values of 132 days and 187 days for total residues)
MRID 41475211
Adsorption coefficients (Kd) (25 [o]C)*
3.77 (Mean of five values: 0.12, 0.78, 2.89, 5.64, and 9.42)
MRID 41475212
*The only batch equilibrium test with non-sterile soils, conducted on M2-SO2 (the terminal degradate).

	Drinking Water from Surface Water Sources

	The Surface Water Concentration Calculator (SWCC v1.106) was used to calculate EDWCs from surface water sources.  There are two citrus modeling scenarios in the SWCC database.  They are California citrus and Florida citrus.  Both scenarios were assessed to obtain EDWCs.  Table 3 lists the application related information and assumptions.  Since sethoxydim is used to control post-emergence annual and perennial grass weeds, the first application date was assumed during the spring time.

Table 3.  Application Information Related to Sethoxydim Use on Citrus Scenarios
Model Input Variable
Input Value
Comments
1[st] Application Date (2 scenarios)
April 1 or April 15
In the spring time
Application Rate (maximum)
0.47 lb a.i./acre (2.5 pints)
Label Information
Maximum Number of Applications
4 (10 pints max. per season)
Label Information
Application Interval
14 days (minimum)
Label Information
Percent Cropped Area
91%
National default for all agricultural land
Application method
Ground
Label Information
App. Efficiency / Spray Drift
0.99 / 0.066 (for ground)
USEPA, 2013

	Standard percent cropped areas (PCA) are used as conservative default estimates of the extent of watershed on which agricultural crops of unknown specific PCA are grown.  Considering the many use sites of sethoxydim, the PCA value of 0.91 was used to represent the national default PCA for all agricultural land.  The PCA-adjusted SWCC results are tabulated in Table 4.  The modeling results of the Florida citrus scenario provided the higher EDWCs of 65.3 μg/L and 6.6 μg/L to represent the 1-in-10-year peak and mean exposure values, respectively.

Table 4.  Sethoxydim Total Residue of Concerns EDWCs from Surface Water Sources
                                      Use
                                 PRZM Scenario
                               Initial App. Date
                      1-in-10-year Peak Exposure (μg/L)
                   1-in-10-year Annual Mean Exposure (μg/L)
                         30-year Mean Exposure (μg/L)
                                Citrus Group 10
                                  CA Citrus
                                    Apr. 1
                                     3.89
                                     0.77
                                     3.38

                                  CA Citrus
                                    Apr. 15
                                     3.90
                                     0.75
                                     3.55

                                  FL Citrus
                                    Apr. 1
                                     65.3
                                      6.6
                                     0.71

                                  FL Citrus
                                    Apr. 15
                                     56.6
                                      6.3
                                     0.68

      The Provisional Cranberry Model is a provisional refinement to the Tier I Rice Model (v1.0, May 8, 2007).  Refinements include the addition of simple degradation processes in dry and flooded conditions and a water depth of twelve inches, rather than the water depth of four inches used in the rice model.  These modifications allow estimation of screening-level peak and annual mean EDWCs of sethoxydim residues of concern that may occur in untreated surface water used as drinking water following use on cranberries.

      The Provisional Cranberry Model is based on the same assumptions as the Tier I Rice Model, with the addition of degradation processes in dry and flood conditions and a water depth of twelve inches in the flooded cranberry bog.  Degradation of sethoxydim residues of concern is assumed to occur predominantly via aerobic microbial metabolism, whether on dry cranberry bog soil or in bog flood water.

      The cranberry bog water depth of twelve inches is a maximum depth recommended by the Cape Cod Cranberry Growers Association.  Previous assessments of mesotrione uses that employed the Provisional Cranberry Model assumed a water depth of eighteen inches (DP barcode 339984, USEPA, 2004; DP barcode 325840, USEPA, 2006a), which is within the range of water depths traditionally used.  However, modern water conservation pressures are causing cranberry growers to reduce the flood depth to fewer inches above the vertical cranberry branches, which grow up to eight inches high.  Therefore, a twelve-inch deep flood is a reasonable refinement to model assumptions.

	The label use of sethoxydim on cranberries at the maximum proposed application rate (0.47 lbs a.i./A) may occur no more than twice times per year, based on the annual application rate limit (0.94 lbs a.i./A).  The minimum reapplication interval is 14 days.  There is a pre-harvest interval (PHI) of 30 days requirement.

      Cranberry bogs are not typically flooded until the night before harvesting.  Therefore, for the parent compound, the proposed single application rate (0.47 lbs a.i./A) was aged on dry soil with the Provisional Cranberry Model for two durations: 44 and 30 days.  Peak and annual mean EDWCs were calculated beginning three days after flooding to account for transport time to a down-gradient drinking water intake following release of bog tailwater not long after flooding.   Model input parameters are listed in Table 5.  Because PCA values were not available for cranberry uses, they were not considered for exposure estimates in this cranberry use.

Table 5.  Provisional Cranberry Model input parameters for total residues of sethoxydim.
Input Parameter
Value
Comments
Source
Application Rate
(lbs a.i./A)
0.47
Maximum single application rate.
Label Information
Applications per Year
2
Maximum number of applications per year at the maximum proposed single application rate.
Label Information
Application intervals (d)
14
Minimum interval
Label Information
Adsorption coefficients (Kd) (25 [o]C)*
3.77
Mean of five values: 0.12, 0.78, 2.89, 5.64, and 9.42
MRID 41475212
Aerobic Soil Metabolism Half-life (days)
54
Upper 90[th] percentile on two values of 30 days and 7 days for total residues)
MRID 41475210
Aerobic aquatic metabolism
half-life (days)
44
Upper 90th percentile on two values of 38.1 days and 32.9 days for total residues
MRID 42165604

      Based on the inputs from Table 5 and the sethoxydim application dates calculated to be 30 days (30 days PHI) and 44 days before flooding, the provisional cranberry model yields the EDWCs of 79.6 μg/L and 13.9 μg/L, respectively for peak value and annual average value.

      Drinking Water from Ground Water Sources

      PRZM-GW (v1.07) is used to calculate EDWCs from ground water sources.  The chemical specific input parameters including hydrolysis half-life, aerobic soil metabolism half-life, and adsorption coefficient (Kd) are taken from Table 2 and application related inputs are taken from Table 3.  All six available scenarios were modeled as surrogates for turf scenarios, with the Florida citrus scenario producing the highest EDWCs as shown in Table 6.  The modeling results of Florida citrus scenario provide the higher EDWCs of 0.565 μg/L and 0.511 μg/L to represent the acute and chronic exposure values, respectively.

Table 6.  PRZM-GW Output of EDWCs for Sethoxydim Total Residue of Concerns
                               Modeled Scenario
                           Max. Daily Conc. (ug/L)
                        Mean Breakthrough Time (years)
                        Post-breakthrough Mean (ug/L)
                                   DMV corn
                                    0.0444
                                     86.12
                                    0.0394
                                   FL citrus
                                     0.565
                                     45.96
                                     0.511
                                   FL potato
                                    0.0656
                                     35.28
                                    0.0585
                                   GA peanut
                                     0.104
                                     67.69
                                    0.0923
                                   NC cotton
                                    0.00225
                                  Incomplete*
                                  Incomplete
                                    WI corn
                                    0.00384
                                  Incomplete
                                  Incomplete
*Incomplete indicates no breakthrough during the modeling simulation

Figure 1. PRZM-GW EDWCs over 100 years for the Florida citrus scenario

      The overall estimated drinking water concentrations from surface water sources and ground water sources are summarized in Table 1.  The surface water concentrations are about two order of magnitudes higher than the ground water concentrations.

Attachment 1.     Molecular Structures of Sethoxydim and Eight Metabolites

      The following scheme represents the relationship between parent sethoxydim (M) and its eight identified degradates.  There are three groups of degradates: a group formed from the parent by oxidation of the sulfur atom (M group), the "amines" or M1 group, and the tetrahydrobenzoxazoles, or M2 group.  The first M1 group daughter (M1-S) is formed by cleavage of the ethoxyimino group to an amino group, either by hydrolysis or aqueous photolysis.  The first member of the M2 group (M2-S) is then formed from M1-S by ring closure to produce a tetrahydrobenzoxazole ring.  Each of the three groups of degradates also has a sulfoxide (-SO) and a sulfone (-SO2), to round out the total of eight degradates.  This reaction dominates in aerobic soil metabolism and soil photolysis experiments, especially to form the M-SO and M-SO2 degradates.

		M Group		M1 Group	M2 Group
		M      		      M1-S             	M2-S

		M-SO 		      M1-SO  		         M2-SO

		M-SO2 	      M1-SO2                   M2-SO2

      The eight degradates include 2 daughter products, which are formed from the parent by a single reaction (M1-S and M-SO), 3 granddaughter products that are two reactions removed from the parent (M-SO2, M2-S, and M1-SO), 2 great-granddaughters that are three reactions removed (M1-SO2 and M2-SO), and one great-great-granddaughter that is four reactions removed (M2-SO2).  It is important to note that M1-SO, M2-SO, M1-SO2, and M2-SO2 may be formed by more than one pathway, and that the sulfur oxidation may be reversible under reducing conditions.


[Federal Register Volume 87, Number 119 (Wednesday, June 22, 2022)]
[Proposed Rules]
[Pages 37249-37252]
[FR Doc No: 2022-13203]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0598; Project Identifier AD-2021-01322-T]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain The Boeing Company Model 777-200, 777-200LR, 777-300, 777-
300ER, and 777F series airplanes. This proposed AD was prompted by
reports of wing anti-ice (WAI) valve failure that can result in
undetected structural damage to leading edge (LE) slat assemblies, and
separately a failure of the autothrottle (A/T) to disconnect after
advancing the throttle levers, which caused a low speed condition
during a go-around. This proposed AD was also prompted by a
determination that insufficient low-speed protection exists in the 777
fleet and a determination that the flightcrew may not recognize and
properly respond to a multi-channel unreliable airspeed event. This
proposed AD would require installing certain new software, and doing a
software configuration check. The FAA is proposing this AD to address
the unsafe conditions on these products.

DATES: The FAA must receive comments on this proposed AD by August 8,
2022.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
     Fax:<PHONE_NUMBER>.
     Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

    For service information identified in this NPRM, contact Boeing
Commercial Airplanes, Attention: Contractual & Data Services (C&DS),
2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600;
telephone<PHONE_NUMBER>; internet https://www.myboeingfleet.com. You may
view this referenced service information at the FAA, Airworthiness
Products Section, Operational Safety Branch, 2200 South 216th St., Des
Moines, WA. For information on the availability of this material at the
FAA, call<PHONE_NUMBER>. It is also available at https://www.regulations.gov by searching for and locating Docket No. FAA-2022-
0598.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2022-0598; or in person at
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays. The AD docket contains this NPRM, any comments
received, and other information. The street address for Docket
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Hassan Ibrahim, Aerospace Engineer,
Systems and Equipment Section, FAA, Seattle ACO Branch, 2200 South
216th St., Des Moines, WA 98198; phone and fax:<PHONE_NUMBER>; email:
[email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include ``Docket No. FAA-2022-0598; Project Identifier
AD-2021-01322-T'' at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as ``PROPIN.'' The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to
Hassan Ibrahim, Aerospace Engineer, Systems and Equipment Section, FAA,
Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone
and fax:<PHONE_NUMBER>; email: [email protected]. Any commentary
that the FAA receives which is not specifically designated as CBI will
be placed in the public docket for this rulemaking.

Background

    The FAA has received reports of WAI valve failure, and determined
that a specific aspect of the WAI system was not fully assessed by the
system safety analysis conducted during type certification. Fleet data
indicates, the WAI valve has failed to open in 50 unique events during
the period from November 2013 through March 2019. High temperature
bleed air (250-400 [deg]F) can unintentionally flow into the LE slat
assemblies due to mechanical failure of the WAI valve or an unintended
command from the airfoil and cowl ice protection system (ACIPS) control
card. This high temperature bleed air exposure, when the airplane is on
the ground and there is minimal airplane speed, can reduce the
structural capability of the slat such that affected structure may not
be able to withstand design limit load during the next flight cycle
(takeoff or landing). The revised software will monitor WAI valve
function and annunciate failures.
    In addition, Boeing received a report that, during landing, after
the A/T had automatically changed to the IDLE A/T mode, the pilot
initiated a go-around by manually advancing the throttle levers to more
than 50 degrees throttle lever angle. During that incident, the A/T did
not disconnect due to advancing the throttle levers, and remained in
IDLE mode with the throttle levers automatically returning to an idle
setting when released, causing a low speed condition during the go-
around. Such a low speed condition can result in a low altitude stall
and potential impact with terrain.
    Boeing developed new Airplane Information Management System 2
(AIMS-2) Block Point (BP) Version 17C software to address the WAI
system failures and A/T not disengaging. Before operators can install
AIMS-2 BP Version 17C software updates, if not done already, they must
install earlier BP versions of this software to ensure all required
software part numbers are installed. Those earlier versions were
released to address other unsafe conditions on the affected airplanes.
One earlier software update was prompted by an accident at San
Francisco International Airport on July 6, 2013 in which the airplane
deviated below the intended glideslope and impacted the seawall as it
crashed short of the runway. The subsequent investigation determined
that insufficient low-speed protection existed in the 777 fleet; AIMS-2
BP Version 17B was developed to expand the A/T system authority and
provide an earlier threshold for the low-airspeed alert. AIMS-2 BP V17B
inadvertently introduced the failure of the A/T to disconnect after
manual throttle advancement during go-around, which led to the
subsequent development of AIMS-2 BP V17C. Another concern addressed by
earlier software updates is the determination that inadequate
flightcrew recognition of, and response to, a multi-channel unreliable
airspeed event, can result in loss of control of the airplane.
    These conditions, if not addressed, could result in undetected
failure of the WAI system and consequent high temperature bleed air
flowing into the LE slat assemblies, along with a low speed condition
on the ground, which could result in reduced structural integrity of
the slat and prevent continued safe flight and landing of the airplane.
In addition, the FAA is also issuing this AD to prevent failure of the
A/T to disconnect after advancing the throttle levers, or insufficient
low energy protection, which could result in controlled flight into
terrain, or a multi-channel unreliable airspeed event could result in
loss of control of the airplane.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe
conditions described previously are likely to exist or develop on other
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 777-31A0342 RB,
dated July 19, 2021. This service information specifies procedures for
installing new AIMS-2 BP Version 17C software, and doing a software
configuration check. For Groups 1, 2, and 3, this service information
also specifies concurrent actions (installation of AIMS-2 BP Version
17B software; installation of AIMS-2 and PlaneNet-2 systems; or
installation of AIMS-2 and software; depending on configuration).
    This service information is reasonably available because the
interested parties have access to it through their normal course of
business or by the means identified in ADDRESSES.

Proposed AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions specified
in the service information already described, except for any
differences identified as exceptions in the regulatory text of this
proposed AD. For information on the procedures and compliance times,
see this service information at https://www.regulations.gov by
searching for and locating Docket No. FAA-2022-0598.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would
affect 353 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:

                                                Estimated Costs *
----------------------------------------------------------------------------------------------------------------
                                                                                Cost on U.S.
             Action                    Labor cost            Parts cost     Cost per  product      operators
----------------------------------------------------------------------------------------------------------------
Install AIMS-2 BP Version 17C    3 work-hours x $85 per  Up to $13,140....  Up to $13,395....  Up to $4,728,435.
 and do software check.           hour = $255.
Install AIMS 2 BP Version 17B    3 work-hours x $85 per  Up to $13,140....  Up to $13,395....  Up to $4,728,435.
 (SB 777-31-0294).                hour = $255.
Install AIMS-2 and PlaneNet-2    Up to 101 work-hours x  Up to $13,140....  Up to $21,725....  Up to $7,668,925.
 (SB 777-31-0331).                $85 per hour = Up to
                                  $8,585.
Install AIMS 2 and software (SB  Up to 106 works-hours   Up to $13,140....  Up to $22,150....  Up to $7,818,950.
 777-21-0322).                    x $85 per hour = Up
                                  to $9,010.
----------------------------------------------------------------------------------------------------------------
* This parts cost is estimated to be the same for the concurrent actions as for the primary actions but the FAA
  does not have any definitive data on which to base the parts cost.

    The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some or all of the costs of
this proposed AD may be covered under warranty, thereby reducing the
cost impact on affected operators.

Authority for This Rulemaking

    Title 49 of the United States 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 Agency's authority.
    The FAA is 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 products identified in this rulemaking action.

Regulatory Findings

    The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not
have a substantial direct effect on the States, on the relationship
between the national Government and the States, or on the distribution
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify this proposed
regulation:
    (1) Is not a ``significant regulatory action'' under Executive
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness
directive:

The Boeing Company: Docket No. FAA-2022-0598; Project Identifier AD-
2021-01322-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive
(AD) by August 8, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 777-200, 777-200LR,
777-300, 777-300ER, and 777F series airplanes, certificated in any
category, as identified in Boeing Alert Requirements Bulletin 777-
31A0342 RB, dated July 19, 2021.

(d) Subject

    Air Transport Association (ATA) of America Code 31, Instruments.

(e) Unsafe Condition

    This AD was prompted by reports of wing anti-ice (WAI) valve
failure that can result in undetected structural damage to leading
edge (LE) slat assemblies, and separately a failure of the
autothrottle (A/T) to disconnect after advancing the throttle
levers, which caused a low speed condition during a go-around. This
AD was also prompted by a determination that insufficient low-speed
protection exists in the 777 fleet and a determination that the
flightcrew may not recognize and properly respond to a multi-

channel unreliable airspeed event. The FAA is issuing this AD to
prevent undetected failure of the WAI system and consequent high
temperature bleed air flowing into the LE slat assemblies, along
with a low speed condition on the ground, which could result in
reduced structural integrity of the slat and prevent continued safe
flight and landing of the airplane. The FAA is also issuing this AD
to prevent failure of the A/T to disconnect after advancing the
throttle levers, or insufficient low energy protection, which could
result in controlled flight into terrain, or a multi-channel
unreliable airspeed event could result in loss of control of the
airplane.

(f) Compliance

    Comply with this AD within the compliance times specified,
unless already done.

(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the
applicable times specified in the ``Compliance'' paragraph of Boeing
Alert Requirements Bulletin 777-31A0342 RB, dated July 19, 2021, do
all applicable actions identified in, and in accordance with, the
Accomplishment Instructions of Boeing Alert Requirements Bulletin
777-31A0342 RB, dated July 19, 2021.
    Note 1 to paragraph (g): Guidance for accomplishing the actions
required by this AD can be found in Boeing Alert Service Bulletin
777-31A0342, dated July 19, 2021, which is referred to in Boeing
Alert Requirements Bulletin 777-31A0342 RB, dated July 19, 2021.

(h) Exceptions to Service Information Specifications

    (1) Where the Compliance Time columns of the tables in the
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
31A0342 RB, dated July 19, 2021, use the phrase ``the original issue
date of Requirements Bulletin 777-31A0342 RB,'' this AD requires
using ``the effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 777-31A0342 RB
specifies contacting Boeing for instructions for upgrading certain
software: This AD requires doing the upgrade using a method approved
in accordance with the procedures specified in paragraph (i) of this
AD.
    (3) Where the description in the Effectivity section of Boeing
Alert Requirements Bulletin 777-31A0342 RB defines Group 1 airplanes
as ``Airplanes with Airplane Information Management System (AIMS)-2
with service bulletin 777-31-0294 incorporated,'' this AD requires
using ``Airplanes with Airplane Information Management System
(AIMS)-2 with a requirement to incorporate service bulletin 777-31-
0294.''
    (4) Where the description in the Effectivity section of Boeing
Alert Requirements Bulletin 777-31A0342 RB defines Group 2 airplanes
as ``Airplanes with AIMS-2 with service bulletin 777-31-0331
incorporated,'' this AD requires using ``Airplanes with AIMS-2 with
a requirement to incorporate service bulletin 777-31-0331.''
    (5) Where the description in the Effectivity section of Boeing
Alert Requirements Bulletin 777-31A0342 RB defines Group 3 airplanes
as ``Airplanes with AIMS-2 with service bulletin 777-31-0332
incorporated,'' this AD requires using ``Airplanes with AIMS-2 with
a requirement to incorporate service bulletin 777-31-0332.''

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle ACO Branch, FAA, has the authority to
approve AMOCs for this AD, if requested using the procedures found
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request
to your principal inspector or responsible Flight Standards Office,
as appropriate. If sending information directly to the manager of
the certification office, send it to the attention of the person
identified in paragraph (j)(1) of this AD. Information may be
emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the responsible Flight Standards Office.
    (3) An AMOC that provides an acceptable level of safety may be
used for any repair, modification, or alteration required by this AD
if it is approved by The Boeing Company Organization Designation
Authorization (ODA) that has been authorized by the Manager, Seattle
ACO Branch, FAA, to make those findings. To be approved, the repair
method, modification deviation, or alteration deviation must meet
the certification basis of the airplane, and the approval must
specifically refer to this AD.

(j) Related Information

    (1) For more information about this AD, contact Hassan Ibrahim,
Aerospace Engineer, Systems and Equipment Section, FAA, Seattle ACO
Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax:
206-231-3653; email: [email protected].
    (2) For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Contractual & Data Services
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone<PHONE_NUMBER>; internet https://www.myboeingfleet.com. You may view this referenced service
information at the FAA, Airworthiness Products Section, Operational
Safety Branch, 2200 South 216th St., Des Moines, WA. For information
on the availability of this material at the FAA, call<PHONE_NUMBER>.

    Issued on June 1, 2022.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness
Division, Aircraft Certification Service.
[FR Doc. 2022-13203 Filed 6-21-22; 8:45 am]
BILLING CODE 4910-13-P


[Federal Register Volume 82, Number 25 (Wednesday, February 8, 2017)]
[Notices]
[Page 9737]
[FR Doc No: 2017-02534]

-----------------------------------------------------------------------

DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

[Docket No. EL17-27-000]

PacifiCorp; Notice of Institution of Section 206 Proceeding and
Refund Effective Date

    On February 2, 2017, the Commission issued an order in Docket No.
EL17-27-000, pursuant to section 206 of the Federal Power Act (FPA), 16
U.S.C. 824e (2012), instituting an investigation into whether the
proposed rate decreases of PacifiCorp are just and reasonable.
PacifiCorp, 158 FERC 61,121 (2017).
    The refund effective date in Docket No. EL17-27-000, established
pursuant to section 206(b) of the FPA, will be the date of publication
of this notice in the Federal Register.
    Any interested person desiring to be heard in Docket No. EL17-27-
000 must file a notice of intervention or motion to intervene, as
appropriate, with the Federal Energy Regulatory Commission, 888 First
Street NE., Washington, DC 20426, in accordance with Rule 214 of the
Commission's Rules of Practice and Procedure, 18 CFR 385.214, within 21
days of the date of issuance of the order.

    Dated: February 2, 2017.
Nathaniel J. Davis, Sr.,
Deputy Secretary.
[FR Doc. 2017-02534 Filed 2-7-17; 8:45 am]
 BILLING CODE 6717-01-P