Thomas D. Ray, V. Vincent Davis Ditmore ( 2022 )


Menu:
  •        IN THE COURT OF APPEALS OF THE STATE OF WASHINGTON
    THOMAS D. RAY,                                   No. 81494-0-I
    Respondent,          DIVISION ONE
    v.
    UNPUBLISHED OPINION
    VINCENT DAVIS DITMORE,
    Appellant.
    CHUN, J. — Thomas Ray brought a negligence suit against Vincent
    Ditmore, claiming damages arising from a ground collision between their
    airplanes. After a bench trial, the trial court determined that Ditmore was solely
    responsible for the collision. Ditmore appeals, claiming Ray’s negligence was
    the sole cause of, or at least contributed to, the collision. For the reasons below,
    we affirm.
    I. BACKGROUND
    A. Facts
    The Arlington Municipal Airport is an “uncontrolled” airport because it does
    not have an air traffic control tower. Federal Aviation Administration Advisory
    Circular (AC) 90-66A § 4(a). Pilots communicate with each other using a
    Common Traffic Advisory Frequency (CTAF), which is a radio “frequency
    designated for the purpose of carrying out airport advisory practices while
    operating to or from an airport without an operational control tower.”
    Aeronautical Information Manual (AIM) § 4-1-9(b)(1).
    Citations and pin cites are based on the Westlaw online version of the cited material.
    No. 81494-0-I/2
    Ellie’s at the Airport is a restaurant just east of Taxiway A. It has large
    windows from which diners can watch airplane traffic. Many pilots fly to the
    airport, park their planes on the East Ramp—which is just east of Taxiway A and
    directly south of Ellie’s—and dine at the restaurant.
    September 15, 2017 was a clear day with excellent visibility. Ray flew his
    Piper PA-18 Super Cub (Cub) to the airport. The Cub is a fixed-wing plane from
    which the pilot has full visibility from the front and the sides. Once Ray landed,
    he turned off his radio and anti-collision lights. He taxied towards Arlington Flight
    Services’ (AFS) self-service fuel station at the north end of the airport, and
    planned to have lunch at Ellie’s.
    Ditmore was also at the airport where his Boeing Stearman biplane was
    undergoing repairs. The body of the Stearman rests at an angle with the nose of
    the plane higher than the tail. The cockpit angles upward facing the nose of the
    plane. As a result, when taxiing in a straight line, the pilot cannot see over the
    nose, in front of the plane. Like driving “a car with the hood up,” the nose
    obscures the pilot’s vision. To avoid taxiing “blindly,” Stearman pilots taxi in an S
    pattern, known as “s-turns” or “s-turning.” As the pilot steers the plane to the left,
    they look to the right side of the plane to see oncoming traffic. As the pilot steers
    to the right, they look to the left side.
    Ray refueled his Cub, maneuvered it onto Taxiway A, and began traveling
    south towards Ellie’s. Simultaneously, Ditmore travelled north on Taxiway A.
    Ditmore turned off Taxiway A and onto the East Ramp as Ray continued taxiing
    south on Taxiway A. Then, Ditmore reentered Taxiway A directly in front of Ray.
    2
    No. 81494-0-I/3
    Ray slowed down and tried to swerve to avoid Ditmore, but the planes collided.
    The “left wing tip of the Super Cub caught on the end strut” of the Stearman.
    Because the “Stearman weighs twice as much” as the Cub, the force of the
    collision lifted the Cub and spun it 180 degrees. It sustained extensive damage
    and was no longer airworthy.
    B. Procedural History
    Ray sued Ditmore for negligence. Ditmore countersued for negligence.
    The matter proceeded to a bench trial.
    Mark Hilsen witnessed the collision and testified to the following: He was
    having lunch at Ellie’s and watching the airport traffic through the windows. He
    saw the Cub taxiing south and the Stearman taxiing north on Taxiway A. The
    Stearman was taxiing straight, not s-turning. The trial court found Hilsen credible
    and afforded his testimony “great weight.”
    Ray testified to the following: While taxiing south on Taxiway A from AFS,
    he did not have his anti-collision lights or radio on. He saw the Stearman taxiing
    north and Ditmore was not s-turning. He saw Ditmore “straddling the line”
    between Taxiway A and the East Ramp. When Ditmore got to the north end of
    the East Ramp, he navigated back onto Taxiway A going north in Ray’s direction.
    Ray did not know what Ditmore was doing, so he “slowed down way before he
    got close” and “started moving to the right . . . as far as I could.” “[A]s [Ditmore]
    got closer to the end of the ramp, there was enough of an angle that it became
    obvious that if I didn’t take drastic action to avoid him, that he was going to
    3
    No. 81494-0-I/4
    collide with my airplane.” Ray tried to avoid the collision by swerving. After the
    collision, Ditmore walked over to Ray and said that he did not see the Cub.
    Ditmore’s testimony contradicted Hilsen’s and Ray’s versions of the
    incident. He testified to the following: “When I came up initially, I did not [see the
    Cub]. I was not looking that far ahead.” Before he entered Taxiway A, he saw
    the Cub at AFS. He planned to refuel where Ray had refueled. Ditmore used his
    radio to announce his intentions to taxi north on Taxiway A to other pilots and
    AFS. He assumed the Cub was parked because its “rotating beacon” or
    “anti[-]collision” lights were off and he did not get a radio response. Ditmore
    entered Taxiway A and s-turned as he taxied north on Taxiway A. He was
    halfway through his fifth s-turn, and he could not see the Cub, when the planes
    collided.
    The trial court found that Ditmore failed to explain why he did not see the
    Cub on the taxiway while he s-turned “a distance of over [two] football fields.”
    The court wrote that it “looked carefully at Mr. Ditmore’s explanation for how the
    accident happened, assessed it against other evidence, and concludes that
    much of Mr. Ditmore’s explanation is unsupported by the evidence and is
    therefore unreliable.” The trial court concluded that Ditmore was solely
    responsible for the collision because he failed to s-turn and thereby failed to “use
    ordinary care to see what was in front of him and his speed and [sic] are the sole
    proximate causes of the collision.” It entered judgment against Ditmore and
    awarded Ray $84,047.65 in damages plus statutory costs and attorney fees.
    Ditmore appeals.
    4
    No. 81494-0-I/5
    II. ANALYSIS
    A. Negligence Per Se
    Ditmore suggests that Ray’s non-compliance with Federal Aviation
    Regulations (FARs), and certain provisions of the AIM and certain ACs,
    constitutes negligence per se.1 He says the court should have found “negligence
    as a matter of law” because Ray failed to: (1) illuminate his anti-collision lights;
    (2) monitor his radio while taxiing; (3) see and avoid the collision; (4) keep proper
    distance; (5) follow taxi procedures; and (6) maintain a current medical
    certification.
    Under traditional negligence per se doctrine, “the violation of a statute or
    administrative regulation establishes the elements of duty and breach.” Williams
    v. Leone & Keeble, Inc., 
    170 Wn. App. 696
    , 718, 
    285 P.3d 906
     (2012). But with
    few exceptions not at issue here, in 1986, our legislature abolished the doctrine.
    RCW 5.40.050 (“a breach of a duty imposed by statute, ordinance or
    1
    On a related note, Ditmore says that “[s]tate tort remedies, like this action for
    property damage, are not preempted, but the standard of care that applies to such tort
    actions is defined exclusively by federal rules, regulations, and statutes.” He contends
    the FARs and AIM govern a pilot’s reasonable duty of care and preempt the state’s
    common law standard of care. Ditmore raises this argument for the first time on appeal
    and we need not address it. RAP 2.5(a) (“The appellate court may refuse to review any
    claim of error which was not raised in the trial court.”).
    Also, in advancing this theory, Ditmore relies on the Ninth Circuit’s opinion in
    Montalvo v. Spirit Airlines, which states, “The FAA, together with federal air safety
    regulations, establish complete and thorough safety standards for interstate and
    international air transportation that are not subject to supplementation by, or variation
    among, states.” 
    508 F.3d 464
    , 473–74 (9th Cir. 2007). But the Ninth Circuit’s opinion in
    Martin ex rel. Heckman v. Midwest Express Holdings, Inc. clarified Montalvo: “[W]hen
    the agency issues ‘pervasive regulations’ in an area, like passenger warnings, the FAA
    preempts all state law claims in that area. In areas without pervasive regulations or
    other grounds for preemption, the state standard of care remains applicable.” 
    555 F.3d 806
    , 811 (9th Cir. 2009). Ditmore does not show that there are such pervasive
    regulations in the context of this case.
    5
    No. 81494-0-I/6
    administrative rule shall not be considered negligence per se but may be
    considered by the trier of fact as evidence of negligence”); Pettit v. Dwoskin, 
    116 Wn. App. 466
    , 472, 
    68 P.3d 1088
     (2003) (under the doctrine, “the duty imposed
    was absolute, and the question of actual negligence was irrelevant. But the
    doctrine of negligence per se is no longer viable in Washington. Rather, violation
    of a legal requirement is evidence of negligence.”). In suggesting that the
    doctrine applies, Ditmore relies on cases that predate the doctrine’s abolition and
    do not apply.2
    Given the foregoing, negligence per se does not apply.
    B. Negligence & Contributory Negligence
    Ditmore contends that the FARs and certain federal guidelines set forth
    the standards of care in this matter. He asserts that the trial court misunderstood
    these standards. Ditmore also contends the court erred in failing to attribute
    sole, or at least some, responsibility for the collision to Ray. He says that but for
    Ray’s failure to illuminate his anti-collision lights, monitor his radio while taxiing,
    see and avoid the collision, keep proper distance, follow taxi procedures, and
    maintain a current medical certification, the collision would not have occurred.
    Because the trial court did not commit legal error, substantial evidence supports
    2
    See, e.g., Rathvon v. Columbia Pac. Airlines, 
    30 Wn. App. 193
    , 207, 
    633 P.2d 122
     (1981) (“We have no difficulty with the concept of holding that violations of the
    [FARs], like violations of any other regulations, may constitute negligence per se, under
    appropriate circumstances.”) (emphasis added); Mills v. Orcas Power & Light Co., 
    56 Wn.2d 807
    , 820–21, 
    355 P.2d 781
     (1960) (considering the duty of care a power
    company that maintained power lines next to an active airport owed to planes midflight
    and whether the common law duties of care for trespassers, licensees, and invitees
    apply to planes); Baker v. United States, 
    417 F. Supp. 471
     (W.D. Wash. 1975)
    (considering the Federal Torts Claims Act, 28 U.S.C., § 1346 et seq.).
    6
    No. 81494-0-I/7
    the trial court’s findings, and those findings support its conclusion that Ditmore
    solely caused the collision, we affirm.
    In Crosby v. Cox Aircraft Company of Washington, our Supreme Court
    held that general principles of negligence control questions of aircraft owner and
    operator liability for ground damage. 
    109 Wn.2d 581
    , 583, 589–90, 
    746 P.2d 1198
     (1987) (“[O]wners and operators of flying aircraft are liable for ground
    damage caused by such aircraft only upon a showing of negligence.”). The court
    explained, “The causes of aircraft accidents are legion and can come from a
    myriad of sources. . . . In such circumstances the imposition of liability should be
    upon the blameworthy party who can be shown to be at fault.” 
    Id. at 588
    .
    To recover on a claim of negligence, an injured party must show (1) the
    existence of a duty, (2) breach of that duty, (3) resulting injury, and (4) the breach
    as the proximate cause of that injury. Johnson v. Liquor & Cannabis Bd., 
    197 Wn.2d 605
    , 611, 
    486 P.3d 125
     (2021). The existence of a legal duty in a
    negligence case is a legal question we review de novo. C.L. v. Dep’t of Soc. &
    Health Servs., 
    200 Wn. App. 189
    , 196, 
    402 P.3d 346
     (2017).
    Proximate cause has two elements: cause in fact and legal causation.
    M.E. through McKasy v. City of Tacoma, 15 Wn. App. 2d 21, 33, 
    471 P.3d 950
    (2020). “Cause in fact, or ‘but for’ causation, refers to the ‘physical connection
    between an act and an injury.’ The plaintiff ‘must establish that the harm suffered
    would not have occurred but for an act or omission of the defendant.’” Martini v.
    Post, 
    178 Wn. App. 154
    , 164, 
    313 P.3d 473
     (2013) (citation omitted) (quoting
    Hartley v. State, 
    103 Wn.2d 768
    , 779, 
    698 P.2d 77
     (1985); Joyce v. Dep’t of
    7
    No. 81494-0-I/8
    Corr., 
    155 Wn.2d 36
    , 322, 
    119 P.3d 825
     (2005)). Cause in fact is normally a
    question of fact for the trier of fact. Meyers v. Ferndale Sch. Dist., 
    197 Wn.2d 281
    , 289, 
    481 P.3d 1084
     (2021). Legal causation “involves a policy
    determination as to how far the consequences of an act should extend and is
    generally a legal question.” M.E., 15 Wn. App. 2d at 33.
    Under RCW 4.22.070, with some exceptions not applicable here, “[i]n all
    actions involving fault of more than one entity, the trier of fact shall determine the
    percentage of the total fault which is attributable to every entity which caused the
    claimant’s damages.”
    We review a trial court’s factual findings for substantial evidence, “asking
    whether the record contains evidence sufficient to convince a rational, fair-
    minded person that the finding is true.” Pacific Coast Shredding L.L.C. v. Port of
    Vancouver, USA, 14 Wn. App. 2d 484, 501, 
    471 P.3d 934
     (2020). “‘There is a
    presumption in favor of the trial court’s findings.’” Andren v. Drake, 14 Wn. App.
    2d 296, 306, 
    472 P.3d 1013
     (2020) (quoting State v. Merrill, 
    183 Wn. App. 749
    ,
    755, 
    335 P.3d 444
     (2014)). The burden of showing that a finding of fact is
    unsupported by substantial evidence rests with the party claiming error. State v.
    Lowery, 15 Wn. App. 2d 129, 138, 
    475 P.3d 505
     (2020). Following a bench trial,
    we review de novo a trial court’s conclusions of law. Rufin v. City of Seattle, 
    199 Wn. App. 348
    , 355, 
    398 P.3d 1237
     (2017); Ensberg v. Nelson, 
    178 Wn. App. 879
    , 886, 
    320 P.3d 97
     (2013).
    8
    No. 81494-0-I/9
    1. Anti-Collision Lights
    Ditmore contends that the trial court should have determined that Ray’s
    breach of the duty to illuminate the Cub’s anti-collision lights caused or
    contributed to the collision.3
    The trial court determined that Ray breached the standard of care by not
    illuminating the lights, but that the breach was not the proximate cause of the
    collision:
    Dr. Ray had wing lights on his Piper Cub. He did not turn them on
    when he started his engine, which was a breach of the standard of
    care. However, because the day was a bright, sunny day, and
    because Dr. Ray and Mr. Ditmore both had unobstructed views of
    each other for 4500’ along Taxiway A, and there were no other
    aircraft or other distractions to obscure Dr. Ray’s airplane from
    Mr. Ditmore’s view, Dr. Ray’s failure to turn on the lights is not a legal
    proximate cause of the collision. Had Mr. Ditmore fulfilled his duty to
    see what could be seen by an ordinary person, the collision would
    not have occurred.
    (Emphasis added.)
    The trial court found that Ditmore was taxiing straight rather than s-turning.
    Hilsen and Ray testified that Ditmore was not making s-turns, so he could not
    see in front of the Stearman. Ray testified that because Ditmore could not see
    over the nose of the Stearman, “[h]e would have been unable to see if I had
    3
    Ditmore assigns error to finding of fact 16, which states, “Dr. Ray’s Piper Cub
    was equipped with wing lights that were operational, but Dr. Ray did not have them on at
    any time relevant to these proceedings.” Ditmore says the issue involved Ray’s “rotating
    red beacon” lights, not “wing lights.” Ray did not dispute that his beacon lights were off.
    And he responds that “[i]t is clear from the testimony and argument at trial, however, the
    only lights the trial court could reasonably be referring to were [my] rotating, anti-collision
    light/beacon.” At trial, no one used the term “wing lights.” Instead, witnesses testified
    only about “beacon lights,” “anti-collision lights,” and “strobe lights.” There was a
    consensus that beacon lights and anti-collisions lights are the same thing, but strobe
    lights are different. While the terminology is different, substantial evidence supports the
    trial court’s findings that the Cub had working beacon lights on its wings and that those
    lights were not illuminated.
    9
    No. 81494-0-I/10
    lights or not.” Because Ditmore’s own plane obstructed his view, the lights would
    have done little, if anything, to make the Cub more visible to Ditmore. Thus,
    substantial evidence supports the trial court’s findings that Ditmore’s own plane
    obstructed his view, and that finding supports its determination that but for
    Ditmore’s failure to see, the collision would not have occurred.
    2. Radio Communication
    Ditmore assigns error to finding of fact 36, specifically challenging the
    statement that “[p]ilots are discouraged from using radios when they are on the
    ground because it can interfere with the needs of pilots who are airborne.”
    Ditmore also contends the trial court should have determined that Ray owed him
    a duty to monitor his radio under AIM § 4-1-9(g)(1)-(2) and AC 90-66B
    § 10.1.1.5.4 He contends that Ray’s failure to monitor the radio caused or
    contributed to the collision.
    Substantial evidence supports finding of fact 36. Ditmore testified that
    when he radioed his intent, AFS responded, “I have not heard that in a long
    time.” He testified that he understood AFS’s response to mean, “[T]here is not a
    lot of people really adhering to protocol, ground operation protocol at the
    Arlington Airport.” AFS’s response indicates that it is not local procedure for
    pilots to announce their intent to taxi over the radio. That response also tracks
    4
    AC 90-66B postdates the collision. It replaced AC 90-66A (1993) and AC 90-
    42F (1990), which were in effect at the time of the incident, and which we consider here.
    The ACs’ practices and procedures supplement the AIM. AC 90-42F § 5(a) (“In the
    Interest of promoting safety, the Federal Aviation Administration, through its Airman’s
    Information Manual, Airport Facility Directory, Advisory Circular, and other publications
    provides frequency information, good operating practices, and procedures for pilots to
    use when operating to and from an airport without an operating control tower.”).
    10
    No. 81494-0-I/11
    Ray’s testimony and understanding that “federal an [sic] air regulations now
    discourage communication on the ground, because they want that frequency to
    be available for airplanes that are in the air or in the process of taking off or
    landing.” The foregoing constitutes substantial evidence supporting the finding.
    Next, we consider Ditmore’s contention that even if ground communication
    is discouraged, the court should have determined that Ray owed him a duty to
    monitor his radio even while on the ground under three provisions of AIM § 4-1-9.
    First, Ditmore cites the part of AIM § 4-1-9(a)(1) that states, “To achieve
    the greatest degree of safety, it is essential that all radio-equipped aircraft
    transmit/receive on a common frequency identified tor the purpose of airport
    advisories.” But this focuses on the importance of using a common frequency
    versus monitoring the radio. AIM § 4-1-9(a)(1) also states,
    There is no substitute for alertness while in the vicinity of an airport.
    It is essential that pilots be alert and look for other traffic and
    exchange traffic information when approaching or departing an
    airport without an operating control tower. This is of particular
    importance since other aircraft may not have communication
    capability or, in some cases, pilots may not communicate their
    presence or intentions when operating into or out of such airports.
    This part of AIM § 4-1-9(a)(1) focuses on being alert, looking for other traffic, and
    exchanging information as not all pilots will have communication capability or
    announce their presence or intent. Its terms do not impose a duty to monitor the
    radio; and it acknowledges that some aircraft may not have communication
    capability. And as discussed above, here, substantial evidence supports the
    finding that pilots were discouraged from using the radio while on the ground.
    Likewise, as discussed below, Hilsen understood that AIM was merely advisory.
    11
    No. 81494-0-I/12
    Second, Ditmore cites AIM § 4-1-9(c)(1) for the proposition that “all pilots
    are required to ‘monitor/communicate’ on the appropriate frequency when
    operating aircraft at or near a noncontrolled airport.” But this misconstrues AIM
    § 4-1-9(c)(1), which states in pertinent part that “[p]ilots of inbound traffic should
    monitor and communicate as appropriate on the designated CTAF from 10 miles
    to landing.” Ray had his radio on while he was inbound, and turned it off when
    he landed. To the extent that AIM § 4-1-9(c)(1) establishes a duty to monitor the
    radio, Ray did not breach the duty by turning the radio off after he landed.
    Third, Ditmore cites AIM § 4-1-9(g)(1)-(2), which provide that pilots should
    “self-announce” their “position or intended flight activity or ground operation on
    the designated CTAF” at airports without a flight service station and operating air
    control tower. While AIM § 4-1-9(g)(1)-(2) instruct pilots to use self-announce
    procedures, it does not impose a duty to monitor the radio.
    To the extent that AIM § 4-1-9 establishes a duty to monitor the radio,
    Ditmore has not shown how Ray breached the duty by turning the radio off after
    he landed.5
    5
    Notably, Hilsen testified as to his understanding that AIM is “advisory not
    regulatory,” suggesting that it is customary for pilots at the Arlington Municipal Airport
    use the AIM as non-binding guidance. And we recognize that courts may look to
    common customs and practices to determine the standard of care. See, e.g., Helling v.
    Carey, 
    83 Wn.2d 514
    , 518–19, 
    519 P.2d 981
     (1974) (determining industry standard
    based on common custom in ophthalmology); RESTATEMENT (SECOND) OF TORTS § 295A
    (1965) (“In determining whether conduct is negligent, the customs of the community, or
    of others under like circumstances, are factors to be taken into account, but are not
    controlling where a reasonable man would not follow them.”).
    12
    No. 81494-0-I/13
    3. See & Avoid
    Ditmore contends that the trial court erred in making a number of findings
    of fact about Ditmore’s speed and Ray’s ability to see and avoid Ditmore. He
    also contends that the trial court applied the wrong standard of care and erred by
    not concluding that Ray owed him a duty to “see and avoid” under 
    14 C.F.R. § 91.113
    (b) and (e), breached that duty, and caused or contributed to the
    collision.
    First, Ditmore assigns error to findings of fact 20, 21, 22, 23, and 24,
    which state:
    20. Mr. Ditmore taxied the Stea[r]man north on Taxiway A at a
    higher rate of speed and did not make S turns.
    21. As Mr. Ditmore’s plane approached the East Ramp, it began to
    straddle the line between the East Ramp area and the taxiway.
    22. Dr. Ray knew that the Stearman would eventually either need
    to stop in the East Ramp or return to the taxiway because there
    is a ditch at the north end of the East Ramp. Consequently,
    Dr. Ray slowed further and moved his plane to the west (away
    from Mr. Ditmore’s possible pathway), in an effort to understand
    and anticipate Mr. Ditmore’s actions.
    23. As Mr[.] Ditmore approached the end of the ramp, he did not
    stop. He suddenly turned the plane 30 to 40 degrees to the
    west, placing him on an immediate collision course with
    Dr. Ray’s Piper Cub.
    24. Dr. Ray attempted to avoid the collision by also turning his
    plane sharply west.
    When a trial court has weighed the evidence, this court “‘will not substitute [its]
    judgment for the trial court’s, weigh the evidence, or adjudge witness credibility.’”
    Winter v. Dep’t of Soc. & Health Servs., 12 Wn. App. 2d 815, 839, 
    460 P.3d 667
    (2020) (quoting In re Marriage of Greene, 
    97 Wn. App. 708
    , 714, 
    986 P.2d 144
    (1999)). Ditmore’s challenge to these findings of fact require us to reassess
    13
    No. 81494-0-I/14
    Ditmore’s, Ray’s, and Hilsen’s credibility, and reweigh evidence, both of which
    we will not do on appeal.
    Moreover, substantial evidence supports these findings. Ray testified that
    he saw Ditmore taxiing north, “straddling the line . . . between the ramp and the
    taxiway,” and not making s-turns. Hilsen also saw Ditmore “taxiing fast” and
    “taxiing straight, not S turning.” Ray said that he did not know what Ditmore was
    doing, so he slowed down to gauge if there was room to pass and moved the
    Cub “to the right as far as [he] could.” Based on Ditmore’s location, Ray testified
    that Ditmore needed either to stop or “get back on the taxiway.” Ray said that,
    because Ditmore was moving closer to the end of the East Ramp, he realized
    that if he did not take drastic action, there would be a collision. Ray saw Ditmore
    get back onto the taxiway, and responded by swerving. Hilsen testified that he
    saw Ray “trying to figure out what to do” and saw him make a “40-degree right
    turn.” While Ray saw and tried to avoid the Stearman, he did not do so in time.
    By contrast, no evidence shows that Ditmore saw the Cub and tried to
    avoid the collision. In fact, Ray said that, after the collision, Ditmore told him that
    he did not see the Cub, and Ditmore testified that he did not see the Cub when
    they collided.
    Second, Ditmore contends that the trial court applied the wrong standard
    of care and erred by not concluding that Ray owed him a duty to “see and avoid”
    under 
    14 C.F.R. § 91.113
    (b) and (e). 
    14 C.F.R. § 91.113
    (b) provides,
    When weather conditions permit, regardless of whether an operation
    is conducted under instrument flight rules or visual flight rules,
    vigilance shall be maintained by each person operating an aircraft so
    14
    No. 81494-0-I/15
    as to see and avoid other aircraft. When a rule of this section gives
    another aircraft the right-of-way, the pilot shall give way to that
    aircraft and may not pass over, under, or ahead of it unless well clear.
    (Emphasis added). 
    14 C.F.R. § 91.113
    (e) provides, “When aircraft are
    approaching each other head-on, or nearly so, each pilot of each aircraft shall
    alter course to the right.” While not using the term “see and avoid,” the trial court
    concluded both Ray and Ditmore “had a duty to exercise ordinary care to avoid a
    collision when operating their planes while taxiing,” and “a duty to see what
    would be seen by a person exercising ordinary care.”
    Ditmore contends the trial court erred by not concluding that Ray
    breached the duty to see and avoid, and by not concluding that Ray’s breach
    caused or contributed to the collision. Ditmore says Ray “could have easily
    avoided Ditmore’s plane had he exercised vigilance sooner than he did.”
    The court concluded that Ray operated the Cub with ordinary care and
    “saw what was available to see as he piloted his plane south on the taxiway.” In
    determining that Ditmore’s breach was the proximate cause of the collision, the
    trial court concluded that Ditmore did not operate the Stearman with ordinary
    care and his “failure to make S turns caused him to not see what was available to
    see in front of him (i.e., Ray’s Piper Cub).” It also determined that “[b]ecause
    Ditmore’s taxing speed was too fast for the conditions, he deprived Dr. Ray of
    valuable time he needed to attempt to avoid the collision.”
    Findings of fact 20, 21, 22, 23, and 24, support the court’s conclusion that
    Ditmore’s speed and failure to make s-turns “deprived Dr. Ray of valuable time
    15
    No. 81494-0-I/16
    he needed to attempt to avoid the collision.” Thus, the trial court did not err with
    respect to any failure by Ray to see and avoid Ditmore’s plane.
    4. Keeping Proper Distance
    Ditmore correctly notes that he and Ray had a concurrent duty to keep a
    proper distance under 
    14 C.F.R. § 91.111
    (a), which provides, “No person may
    operate an aircraft so close to another aircraft as to create a collision hazard.”
    Ditmore contends the trial court erred when it attributed sole liability to him. He
    says the court should have determined that Ray concurrently breached the duty
    to keep proper distance.
    Ditmore asserts that Ray admitted there would not be enough room for the
    planes to pass each other safely on the taxiway. But Ray testified that if the
    planes positioned their wheels to the edge of the taxiway, as is “common
    procedure [when] people . . . taxi toward each other, . . . there would be ample
    room for both” planes to pass without their wings touching. Ray also provided a
    scale drawing depicting the space the planes would have had to pass. Ray
    explained that by the time Ditmore pulled onto Taxiway A from the East Ramp,
    Ray was “pretty much close to the corner of the ramp.” Ray said he was beyond
    the other taxiways where he could have safely pulled off to avoid the collision.
    As discussed above, the court’s findings support its conclusion that
    Ditmore’s speed and failure to make s-turns “deprived Dr. Ray of valuable time
    he needed to attempt to avoid the collision” and that Ditmore was the sole
    proximate cause of the collision. Thus, the court did not err.
    16
    No. 81494-0-I/17
    5. Taxi Procedure
    Ditmore contends the trial court erred by not determining that Ray owed
    him a duty to follow taxi procedures, Ray breached that duty, and that breach
    caused or contributed to the collision. But Ditmore cites no FARs, AIM, or ACs to
    support this contention. Thus, he fails to show how the trial court erred.6
    6. Medical Certification
    Ditmore contends the trial court failed to recognize Ray was “negligent as
    a matter of law” for operating the Cub without proper medical certification. 
    14 C.F.R. § 61.23
     requires pilots to maintain certain medical certificates depending
    on the type of piloting they are doing. See also 
    14 C.F.R. § 68.3
     (requiring the
    completion of a medical education course, which also requires a medical
    certification). However, we consider violations of FARs as evidence of
    negligence and not negligence per se. See RCW 5.40.050.
    Preliminarily, the trial court did not consider the evidence of Ray’s lack of
    medical certification, finding it inadmissible under ER 403 and 404(b). Ditmore
    does not challenge this evidentiary decision, so we need not consider his
    contention that Ray’s lack of medical certification caused or contributed to the
    collision.
    6
    Ditmore says the taxiway was one-directional. And he correctly notes that
    Hilsen testified that “taxiways are one directional.” But Hilsen also testified that “[t]he
    culture in aviation is that if you can see somebody coming, that if there is a place to turn
    off, we turn off.” And Ray testified that he was beyond any possible place to turn off
    when Ditmore reentered Taxiway A.
    17
    No. 81494-0-I/18
    Even if we did consider the contention, it lacks merit. The trial court
    concluded:
    [T]he evidence suggests, but was not conclusive, that Dr. Ray should
    have had certain medical documentation in place before operating
    his plane on the date of this collision. Assuming without deciding that
    Mr. Ditmore presented sufficient evidence on this subject, it does not
    change the outcome. First, Dr. Ray’s medical history is irrelevant to
    the collision that is at issue in this case. . . . Had the court considered
    the evidence, it also would not have changed the outcome because
    any duty that Dr. Ray had to have different medical documentation
    in place on the date of this collision cannot be said to have been a
    duty owed to Mr. Ditmore, therefore any breach of the duty is not a
    legal proximate cause of the September 15, 2017 collision.
    Ditmore contends the court should have determined “the accident would not have
    occurred but for Ray’s decision to violate the FARs and fly without medical
    certification.” But Washington courts have rejected similar arguments in the
    context of automobile accidents. See, e.g., Weihs v. Watson, 
    32 Wn.2d 625
    ,
    629, 
    203 P.2d 350
     (1949) (where an unlicensed truck driver failed to stop at a
    stop sign, the court held, “Whether or not the driver of the truck possessed a
    license, the accident would, under the facts of the case, have occurred just the
    same”); Kappelman v. Lutz, 
    141 Wn. App. 580
    , 586, 
    170 P.3d 1189
     (2007) (the
    trial court did not abuse its discretion in refusing to admit evidence that the
    motorcycle driver was unlicensed because it was “not relevant to how and why
    he drove his motorcycle in the way he did on the evening of this accident, only
    his driving conduct is relevant”). Any lack of medical certification did not relate to
    the cause of the accident.
    18
    No. 81494-0-I/19
    C. Remaining Challenges to Findings of Fact
    In addition to findings of fact 16, 20, 21, 22, 23, 24, and 36, discussed
    above, Ditmore challenges findings of fact 18, 28, 29, 30, 31, 32, 34, and 35.
    Ditmore does not support his challenge to findings of fact 18, 28, and 30 with
    argument, so those findings are not properly before us. Findings of fact 29, 31,
    32, 34, and 35, are properly before us yet supported by substantial evidence.
    Ditmore assigns error to findings of fact 18, 28, and 30, but does not
    present supporting argument. To challenge a finding of fact on appeal, the
    appellant must “present argument to the court why specific findings of fact ‘are
    not supported by the evidence and . . . cite to the record to support that
    argument.’” In re Disciplinary Proceeding Against Cottingham, 
    191 Wn.2d 450
    ,
    462, 
    423 P.3d 818
     (2018) (alteration in original) (quoting In re Disciplinary
    Proceeding Against Haskell, 
    136 Wn.2d 300
    , 311, 
    962 P.2d 813
     (1988)). We
    “will only review a claimed error which is included in an assignment of error or
    clearly disclosed in the associated issue pertaining thereto.” RAP 10.3(g). “A
    party abandons assignments of error to findings of fact if it fails to argue them in
    its brief.” Valley View Indus. Park v. City of Redmond, 
    107 Wn.2d 621
    , 630, 
    733 P.2d 182
     (1987). Because Ditmore does not support his challenges to findings of
    fact 18, 28, and 30 with argument, he abandons them and they are verities on
    appeal.
    Ditmore contends findings of fact 29, 31, 32, 34, and 35 conflict with the
    trial testimony. Ray responds that Ditmore’s assignments of error to these
    findings are “a challenge to witness credibility and the persuasiveness of the
    19
    No. 81494-0-I/20
    evidence,” which this court should not reweigh. We agree with Ray that the
    challenges to these findings hinge on witness credibility and thus we do not
    consider them.
    When a trial court has weighed the evidence, this court “‘will not substitute
    [its] judgment for the trial court’s, weigh the evidence, or adjudge witness
    credibility.’” Winter, 12 Wn. App. 2d at 839 (quoting In re Marriage of Greene, 97
    Wn. App. at 714). Ditmore’s challenges to these findings of fact require analysis
    the appellate court may not undertake.
    Findings of fact 31 and 32 provide:
    31. The court finds the testimony of Mr. Mark Hils[e]n to be credible
    and has afforded it great weight. Mr. Hils[e]n obtained his law
    degree in 1986, worked for the Lee Smart law firm after he
    graduated from law school, and began flying commercially for
    United Airlines in 1987. Over the course of his career,
    Mr. Hils[e]n captained both the 747 and the 777. He retired
    from United in 2017. He continues to fly private aircraft and to
    volunteer his time as a flight instructor. He has extensive flight
    instructor qualifications and has been instructing others since
    he was 18 years old. He has experience with both planes
    involved in this collision. He has become extremely familiar with
    the Stearman biplane through his daughter, who owns and
    pilots her own Stearman.
    32. Mr. Hils[e]n witnessed the collision. Through his testimony, he
    explained that he and a friend were sitting in Ellie’s restaurant,
    looking out the picture window that faces Taxiway A. He
    observed both planes; the Piper Cub was about 300 feet away
    from him, and the Stearman was about 900 feet away from him,
    when he first saw each. He did not necessarily observe the
    planes at the same time. He noticed that the Piper Cub was
    taxiing at a normal to slow taxi speed. He took note that the
    Stearman was not making S turns and was taxiing fast, between
    7 & 11 knots.
    The findings depend on the credibility of Hilsen’s and Ray’s testimony.
    20
    No. 81494-0-I/21
    Finding of fact 29 provides,
    Mr. Ditmore described the accident differently. Mr. Ditmore admits
    that he did not see Dr. Ray’s Piper Cub, but asserts that he was
    deceived into believing that the Piper Cub was not on the taxiway
    because the plane’s wing lights were not illuminated when he says
    he saw the plane at the fuel depot. The court looked carefully at
    Mr. Ditmore’s explanation for how the accident happened, assessed
    it against other evidence, and concludes that much of Mr. Ditmore’s
    explanation is unsupported by the evidence and is therefore
    unreliable.
    The trial court weighed the credibility of Ditmore’s testimony and found it
    “unsupported.”
    Findings of fact 34 and 35 state:
    34. Mr. Hils[e]n testified that the Stearman’s pace did not alarm him
    because he assumed that the pilot had seen the Piper Cub and
    was trying to quickly maneuver to a parking place in front of
    Ellie’s Restaurant. When the Stearman was approximately 50
    to 75 feet before the end of the East Ramp, Mr. Hils[e]n realized
    that the Stearman was not going to turn east and park, he
    realized the pilot was going to continue northbound on the
    taxiway. He saw Dr. Ray straining against his shoulder straps,
    looking over his plane, trying to figure out what to do and where
    to go. He saw the Piper Cub make an emergency evasive
    maneuver to try to avoid the collision and described that the
    effort almost worked, but that the Piper Cub’s wing tip caught
    on the Stearman’s end strut. He testified that the Stearman is
    a much heavier plane than the Piper Cub and when the collision
    occurred, the Stearman violently picked up the Super Cub and
    flipped it 180 degrees. He also saw a piece of the Super Cub
    shoot up out of the plane.
    35. After hearing the contested testimony and considering it in the
    light of all of the other evidence, the court concludes that
    Mr. Ditmore was not making S turns when he taxied the
    Stearman in the East Ramp area and that he was also taxiing
    at a speed that was not safe for the conditions.
    To challenge these findings, Ditmore cites his own testimony, “Did four and a half
    S-turns by the time . . . the airplane went come [sic] and struck my left wing
    strut.” But when the court looked closely at Ditmore’s explanation of the collision,
    21
    No. 81494-0-I/22
    assessing it against the other evidence, it concluded that the explanation was
    unreliable. The court found Hilsen credible and afforded his testimony great
    weight. Hilsen testified Ditmore did not perform s-turns and Ditmore’s failure to
    perform s-turns, exacerbated by his speed, was dangerous. He also testified that
    the use of anti-collision lights was unlikely to have changed the outcome because
    airplanes are big and visible from “a long way[] away.” He said that if Ditmore
    had been making s-turns, he would have seen the Cub. Because we will not
    reweigh credibility determinations, we do not consider Ditmore’s challenges to
    these findings of fact.
    D. Attorney Fees
    Ray contends that Ditmore’s appeal is frivolous and requests attorney fees
    under RAP 18.9. He says no reversible issue exists. We disagree.
    We may order a party who files a frivolous appeal to pay terms or
    compensatory damages to “any other party who has been harmed.” RAP 18.9.
    An appeal is frivolous “if there are no debatable issues on which reasonable
    minds can differ and is so totally devoid of merit that there was no reasonable
    possibility of reversal.” Shrauner v. Olsen, 16 Wn. App. 2d 384, 422, 
    483 P.3d 815
     (2020). “All doubts as to whether the appeal is frivolous should be resolved
    in favor of the appellant.” In re Marriage of Schnurman, 
    178 Wn. App. 634
    , 644,
    
    316 P.3d 514
     (2013). “An appeal that is affirmed simply because the arguments
    are rejected is not frivolous.” 
    Id.
    While Ditmore does not prevail on appeal, his arguments are not so
    devoid of merit that there was no reasonable possibility of reversal. He raised a
    22
    No. 81494-0-I/23
    debatable issue as to whether the trial court erred in finding him solely
    responsible for the collision. We deny Ray’s request for attorney fees under
    RAP 18.9.
    We affirm.
    WE CONCUR:
    23