                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

ANTHONY R. TWARDOWSKI, an             
individual,
               Plaintiff-Appellant,         No. 06-16726
                v.                           D.C. No.
AMERICAN AIRLINES, INC.; AMERICA          CV-05-00237-VRW
WEST AIRLINES, INC.,
            Defendants-Appellees.
                                      

MYRA GAIL KASTE; KEITH KASTE;         
KELVIN KASTE; KENNETH KASTE;
KIM GEORING; KAY KOHRER,                    No. 06-16730
             Plaintiffs-Appellants,
                v.                           D.C. Nos.
                                          CV-05-00381-VRW
NORTHWEST AIRLINES; KLM ROYAL              04-01606-VRW
DUTCH AIRLINES,
            Defendants-Appellees.
                                      




                           9657
9658           TWARDOWSKI v. AMERICAN AIRLINES



DEBRA MILLER; MICHAEL DOBLER,            
               Plaintiffs-Appellants,
                 and
ERNEST-WILLIAM REITSCHEL;
MARSHA DABULIS,
                           Plaintiffs,
                  v.                           No. 06-16746
CONTINENTAL AIRLINES, INC.; AIR                 D.C. Nos.
                                             CV-02-01693-VRW
FRANCE, a French corporation,
             Defendants-Appellees,            04-01606-VRW
                 and
THE BOEING COMPANY; AMERICAN
AIRLINES, INC.; NORTHWEST
AIRLINES, INC.; SPIRIT AIRLINES,
INC; DELTA AIR LINES, INC,
                         Defendants.
                                         

DANIEL WYLIE,                            
               Plaintiff-Appellant,
                v.
AMERICAN AIRLINES, INC.,                       No. 06-16749
              Defendant-Appellee,
                                                D.C. No.
               and                           CV-02-02997-VRW
THE BOEING COMPANY; RECARAO
AIRCRAFT SEATING; WEBER
AIRCRAFT LP,
                       Defendants.
                                         
                TWARDOWSKI v. AMERICAN AIRLINES          9659



ALAN REINING,                           
               Plaintiff-Appellant,
                v.
                                              No. 06-16751
LUFTHANSA AIRLINES,
              Defendant-Appellee,              D.C. No.
                                            CV-03-00344-VRW
               and
AIRBUS INDUSTRIE, GIE,
                        Defendant.
                                        

MICHAEL WILLIAMS, individually as       
personal representative and as
successor in interest to the Estate
of Robert Williams, deceased;
MARK WILLIAMS, individually, and
as successor in interest to the
Estate of Robert Williams,                    No. 06-16752
               Plaintiffs-Appellants,          D.C. No.
                  v.                        CV-03-02181-VRW
AMERICAN AIRLINES, INC.,
             Defendant-Appellee,
              and
THE BOEING COMPANY,
                        Defendant.
                                        
9660          TWARDOWSKI v. AMERICAN AIRLINES



YESMIN A. CANTERBURY; SCOTT           
CANTERBURY,
            Plaintiffs-Appellants,          No. 06-16767
              v.                             D.C. No.
                                          CV-04-04872-VRW
US AIRWAYS,
             Defendant-Appellee.
                                      

SHERRI RAHIM; JAVAID RAHIM,           
             Plaintiffs-Appellants,
                v.
                                            No. 06-16768
CONTINENTAL AIRLINES, INC.,
              Defendant-Appellee,            D.C. No.
                                          CV-04-04870-VRW
               and
THE BOEING COMPANY,
                        Defendant.
                                      
              TWARDOWSKI v. AMERICAN AIRLINES         9661



FRANK S. KLONOSKI; SYDNE E.            
KLONOSKI,
              Plaintiffs-Appellants,
                 v.
BRITISH AIRWAYS, a corporation,
                Defendant-Appellee,
UNITED AIRLINES, INC, a                      No. 06-16771
corporation,
                Defendant-Appellee,           D.C. Nos.
                                           CV-05-02476-VRW
                and                         04-01606-VRW
AUSTRIAN AIRLINES GROUP, a
corporation; TYROLEAN AIRWAYS, a
corporation,
                        Defendants,
DOE SEAT MANUFACTURER; DELTA
AIR LINES, INC,
                        Defendants.
                                       

DIXIE WEBB; DAVID WEBB,                
              Plaintiffs-Appellants,
                v.
AMERICAN AIRLINES; SINGAPORE                 No. 06-16773
AIRLINES LIMITED, a corporation,              D.C. No.
             Defendants-Appellees,         CV-05-02608-VRW
               and
DOE SEAT MANUFACTURER,
                         Defendant.
                                       
9662            TWARDOWSKI v. AMERICAN AIRLINES



BERNARDO A. CONTE; LIDIA CONTE,        
             Plaintiffs-Appellants,          No. 06-16776
               v.                             D.C. Nos.
                                           CV-05-01320-VRW
BRITISH AIRWAYS, PLC,                        04-1606 VRW
              Defendant-Appellee.
                                       

JAN LEENDERS,                          
               Plaintiff-Appellant,          No. 06-16777
               v.
                                              D.C. Nos.
                                           CV-05-01790-VRW
KLM ROYAL DUTCH AIRLINES;
CONTINENTAL AIRLINES INC.,                   04-1606 VRW
            Defendants-Appellees.
                                       

WILLIAM HERBERT SMITH,                 
               Plaintiff-Appellant,          No. 06-16782
                v.
                                              D.C. Nos.
                                           CV-05-02748-VRW
UNITED AIRLINES INC., a
corporation,                                 04-1606-VRW
              Defendant-Appellee.
                                       

RONALD GARDNER; LUANNE                 
GARDNER,
              Plaintiffs-Appellants,         No. 06-16783
                v.                            D.C. No.
VARIG; CONTINENTAL AIRLINES,               CV-05-01131-VRW
INC.; DOE SEAT MANUFACTURER,
             Defendants-Appellees.
                                       
               TWARDOWSKI v. AMERICAN AIRLINES          9663



RICHARD STEIN; CHARLOTTE STEIN,          
              Plaintiffs-Appellants,
                v.                             No. 06-16786
MIAMI AIR CHARTERS; THE BOEING                  D.C. No.
COMPANY; MIAMI AIR                           CV-05-00369-VRW
INTERNATIONAL, INC.,
            Defendants-Appellees.
                                         

TAUFIK RIDANI; JANA FAWN MILLS,          
                Plaintiffs-Appellants,
                  v.
                                               No. 06-16788
KLM ROYAL DUTCH AIRLINES,
                Defendant-Appellee,             D.C. Nos.
                                             CV-04-01092-VRW
                 and                          04-01606-VRW
THE BOEING COMPANY; NORTHWEST
AIRLINES, INC.,
                          Defendants.
                                         

CHARLES COOLURIS,                        
               Plaintiff-Appellant,
                v.
                                               No. 06-16792
UNITED AIRLINES, INC; UAL
CORPORATION,                                    D.C. Nos.
                                             CV-03-03637-VRW
            Defendants-Appellees,
                                               04-1606-VRW
               and
BOEING COMPANY,
                        Defendant.
                                         
9664           TWARDOWSKI v. AMERICAN AIRLINES



MADHAVI PARVATHANENI,                   
individually, as personal
representative, and as successor in
interest to the Estate of Srinivas
Samineni, deceased, and as
Guardian Ad Litem for Aneesh V.
                                              No. 06-16797
Samineni, a minor,
                 Plaintiff-Appellant,          D.C. Nos.
                                            CV-03-03842-VRW
                  v.
                                              04-1606-VRW
SINGAPORE AIRLINES, a corporation,
                Defendant-Appellee,
                 and
INDIAN AIRLINES,
                          Defendant.
                                        

EVELYN PLOTKIN,                         
                Plaintiff-Appellant,
                v.
BRITISH AIRWAYS PLC, a                        No. 06-16801
corporation; BOEING COMPANY,
             Defendants-Appellees,             D.C. Nos.
                                            CV-03-03242-VRW
               and                            04-1606-VRW
FLYING SERVICE ENGINEERING AND
EQUIPMENT, LTD.,
                         Defendant.
                                        
              TWARDOWSKI v. AMERICAN AIRLINES        9665



CHRISTINE BRYNE,                      
               Plaintiff-Appellant,
                v.
UNITED AIRLINES, INC; UAL                   No. 06-16803
CORPORATION,                                 D.C. No.
            Defendants-Appellees,         CV-04-01022-VRW
               and
THE BOEING COMPANY,
                        Defendant.
                                      

MARK WOODS; LAURA SMITH,              
            Plaintiffs-Appellants,
                                            No. 06-16804
              v.
                                             D.C. No.
AIR NEW ZEALAND; DOE SEAT                 CV-05-01733-VRW
MANUFACTURER,
           Defendants-Appellees.
                                      

RICHARD JAFFE; ELLEN JAFFE,           
             Plaintiffs-Appellants,
                                            No. 06-16805
                v.
                                             D.C. No.
EL AL ISRAEL AIRLINES, LIMITED;           CV-04-01807-VRW
AMERICAN AIRLINES, INC.,
            Defendants-Appellees.
                                      
9666           TWARDOWSKI v. AMERICAN AIRLINES



MARSHA SHUMAKER, individually           
and as Guardian Ad Litem for
plaintiffs Ryan Shumaker and
Katie Shumaker; RYAN SHUMAKER,
a minor; KATIE SHUMAKER, a                    No. 06-16831
minor,
               Plaintiffs-Appellants,
                                               D.C. No.
                                            CV-04-04322-VRW
                 v.
UAL CORPORATION; UNITED AIR
LINES, INC.; UNITED AIRLINES INC,
              Defendants-Appellees.
                                        

JAMES C. TEPE, individually, and        
as personal representative and
executor of the Estate of
Rosemary Tepe, Deceased; MARY
THERESE HANKNER; PATRICIA
KREILING; SUSANNE TEPE; PETER
TEPE; JEAN TOLBERT; JEAN
WURTENBERGER; LAWRENCE TEPE;
ANNE TEPE; MARYLIN SEASTROM;                  No. 06-16832
JEROME A. TEPE; MATTHEW TEPE,
               Plaintiffs-Appellants,
                                               D.C. No.
                                            CV-04-04527-VRW
                 v.
AIR NEW ZEALAND; DELTA
AIRLINES; DELTA AIRLINES INC,
             Defendants-Appellees,
                and
THE BOEING COMPANY,
                          Defendant.
                                        
               TWARDOWSKI v. AMERICAN AIRLINES           9667



RONALD SLOSKY,                          
                 Plaintiff-Appellant,         No. 06-16836
                 v.                            D.C. No.
ALASKA   AIRLINES, INC.,                    CV-04-00487-VRW
               Defendant-Appellee.
                                        

JANICE SCHMIDT,                         
                 Plaintiff-Appellant,         No. 06-16837
                 v.                            D.C. No.
CONTINENTAL   AIRLINES, INC.,               CV-03-05538-VRW
               Defendant-Appellee.
                                        

JOSEPH J. LABADIA,                      
                Plaintiff-Appellant,          No. 06-16855
                v.                             D.C. No.
VIRGIN ATLANTIC AIRWAYS, LTD.,              CV-05-02952-VRW
              Defendant-Appellee.
                                        

KAMIL MATYSKA,                          
              Plaintiff-Appellant,
                                              No. 06-16860
              v.
KLM ROYAL DUTCH AIRLINES;                      D.C. Nos.
                                            CV-03-04102-VRW
NORTHWEST AIRLINES, INC.; THE               CV-04-01606-VRW
BOEING COMPANY,
           Defendants-Appellees.
                                        
9668          TWARDOWSKI v. AMERICAN AIRLINES



WILSON OLIVEIRA; PAULA SEIXAS,        
             Plaintiffs-Appellants,         No. 06-16863
               v.
                                             D.C. Nos.
                                          CV-03-04830-VRW
UNITED AIR LINES, INC.; UAL
CORPORATION; BOEING COMPANY,              CV-04-01606-VRW
            Defendants-Appellees.
                                      

TAPA BISWAS; SUSHMITA ROY,            
             Plaintiffs-Appellants,         No. 06-16985
               v.                            D.C. No.
BRITISH AIRWAYS,                          CV-05-01895-VRW
              Defendant-Appellee.
                                      

CYNTHIA RIALS,                        
               Plaintiff-Appellant,
                v.                          No. 06-16987
UNITED AIRLINES; JAPAN AIRLINES;             D.C. No.
DOE SEAT MANUFACTURER; UNITED             CV-05-02493-VRW
AIRLINES, INC,
             Defendants-Appellees.
                                      
              TWARDOWSKI v. AMERICAN AIRLINES        9669



FRANK S. KLONOSKI; SYDNE E.           
KLONOSKI,
             Plaintiffs-Appellants,
                v.                          No. 06-17019
DELTA AIRLINES, INC.; BRITISH                D.C. Nos.
                                          CV-05-02476-VRW
AIRWAYS; AUSTRIAN AIRLINES
GROUP; TYROLEAN AIRWAYS;                    04-1606-VRW
UNITED AIRLINES, INC; DOE SEAT
MANUFACTURER,
            Defendants-Appellees.
                                      

SHAWN HARRIS,                         
               Plaintiff-Appellant,         No. 06-17027
               v.                            D.C. No.
ATA AIRLINES, INC., a corporation,        CV-04-01461-VRW
             Defendant-Appellee.
                                      

CHANNA VAJJALA PRASAD,                
              Plaintiff-Appellant,
                                            No. 06-17028
               v.
                                             D.C. No.
ATA AIRLINES INC.; LUFTHANSA              CV-04-00875-VRW
GERMAN AIRLINES,
           Defendants-Appellees.
                                      
9670            TWARDOWSKI v. AMERICAN AIRLINES



JULIE BRACKENBURY; CHRISTOPHER           
BRACKENBURY,                                   No. 06-17044
             Plaintiffs-Appellants,
               v.                               D.C. No.
                                             CV-05-03873-VRW
VIRGIN ATLANTIC AIRWAYS, LTD.,                   OPINION
              Defendant-Appellee.
                                         
        Appeal from the United States District Court
          for the Northern District of California
        Vaughn R. Walker, District Judge, Presiding

                  Argued and Submitted
          May 12, 2008—San Francisco, California

                       Filed July 30, 2008

     Before: Betty B. Fletcher and Pamela Ann Rymer,
 Circuit Judges, and Kevin Thomas Duffy,* District Judge.

                      Per Curiam Opinion




  *The Honorable Kevin Thomas Duffy, Senior United States District
Judge for the Southern District of New York, sitting by designation.
9672             TWARDOWSKI v. AMERICAN AIRLINES




                             COUNSEL

Clay Robbins, Magana Cathcart & McCarthy, Los Angeles,
California (argued); Randy Baker, Seattle, Washington, for
the plaintiffs-appellants.

William Boyce, Fulbright & Jaworski, Houston, Texas; Rich-
ard Grotch, Coddington, Hicks & Danforth, Redwood City,
California; Samantha D. Hilton, Kenney & Markowitz, San
Francisco, California; Charles L. Coleman, Holland &
Knight, San Francisco, California; Clem C. Trischler, Pietra-
gallo, Bosick & Gordon, Pittsburgh, Pennsylvania (argued);
Sara A. Simmons, Law Offices of Sara A. Simmons, San
Francisco, California; Kevin R. Sutherland, Clyde & Co. US,
Woodland Hills, California; Diane Westwood Wilson, New
York, New York; Jeffrey A. Worthe, Santa Ana, California;
Rod D. Margo, San Francisco, California (argued), for the
defendants-appellees.


                              OPINION

PER CURIAM:

  In these consolidated appeals,1 airline passengers or their
  1
    The cases were transferred to the Honorable Vaughn R. Walker in the
Northern District of California pursuant to order of the Judicial Panel on
Multidistrict Litigation under 28 U.S.C. § 1407, MDL Docket No. 04-
01606. In re Deep Vein Thrombosis Litigation, 323 F. Supp. 2d 1378
(J.P.M.L. 2004). The district court’s judgment is appealed under the lead
case of Miller v. Continental Airlines, Inc. (No. 06-16746). We ordered
the cases consolidated for purposes of appeal. Air New Zealand, Ltd.,
Israel Airlines, Ltd., Japan Airlines, KLM Royal Dutch Airlines, Luf-
                 TWARDOWSKI v. AMERICAN AIRLINES                   9673
survivors appeal from summary judgment in favor of Conti-
nental Airlines and a number of other air carriers on their
claim for damages for failure to warn of the risk of Deep Vein
Thrombosis (DVT) on international flights. They argue that
the airlines’ refusal of requests to warn was an unexpected
event and thus, an “accident” under Article 17 of the Warsaw
Convention, because before their flights, the airlines’ trade
organization, the English House of Lords, and airline medical
officers had urged airlines to warn of DVT risks, and the air-
lines themselves had publicly represented that preventing pas-
senger injury was a priority. However, we have already held
that developing DVT in-flight is not an “accident,” Rodriquez
v. Ansett Australia, Ltd., 383 F.3d 914, 917 (9th Cir. 2004),
and that failing to warn about its risk is not an “event” for
purpose of liability for an “accident” under Article 17, Caman
v. Continental Airlines, Inc., 455 F.3d 1087, 1092 (9th Cir.
2006). Neither requests by public agencies, nor the airlines’
public commitment to safety, converts the failure to warn
about DVT into an event or accident; the gravamen remains,
at its core, a failure to warn. If there is no liability for failure
to warn, there is none for failure to warn effectively. Accord-
ingly, we affirm.

                                    I

   Between 2001 and 2004, passengers or their decedents pur-
chased a plane ticket on an air carrier for an international
flight during which they allegedly incurred injuries and, in
five cases, death, which they attribute to DVT. Deep vein
thrombosis is a medical condition in which a blood clot forms
in the deep veins of the legs. Before their flights, the Interna-

thansa German Airlines, and Singapore Airlines, Ltd. separately filed a
joint brief, as did Yesmin A. Canterbury in her case against US Airways.
Unless necessary for context, we refer to Miller and the other appellants
as “passengers,” and to Continental and the other appellees as “airlines”
or “air carriers.”
9674          TWARDOWSKI v. AMERICAN AIRLINES
tional Air Transport Association (IATA), the English House
of Lords, and airlines’ own medical personnel had suggested
that airlines warn passengers about DVT. For example, in
December 2000, the British House of Lords published a report
suggesting that airlines should make DVT information avail-
able through “high profile pre- and in-flight preventive
advice” as well as “active encouragement of in-flight mobility
and preventive leg exercises.” In a magazine article, the chief
medical officer of United Airlines, Dr. Gary Kohn, said that
United takes extra safety steps and gives passengers tips on
avoiding DVT. And in February 2001, the IATA issued a
press release that stated, among other things, at the present
time, there is no conclusive medical evidence supporting a
connection of DVT with long distance travel; air carriers
should warn passengers of the risk of DVT at the time of
making reservations; and on board, airlines should encourage
passengers to drink sufficient fluids, wear loose fitting
clothes, avoid smoking and alcoholic beverages, and perform
physical exercises in their seats. Air carriers generally put
information about DVT on their websites and in inflight mag-
azines. Air carriers also publically state that preventing pas-
senger injury is a priority.

   Air carriers moved for summary judgment, which the dis-
trict court granted. The court concluded that Caman mostly
controlled, but that, to the extent passengers maintained that
the airlines elected not to give warnings (or effective warn-
ings), those decisions would be too remote from the embark-
ing, disembarking, and on-board process for injury to be
compensable under Article 17. The court allowed discovery
into industry practice and individual airline policy, but
rejected passengers’ Fed. R. Civ. P. 56(f) request for addi-
tional discovery.

  Passengers timely appealed.

                              II

  The United States is party to the Convention for the Unifi-
cation of Certain Rules Relating to International Transporta-
               TWARDOWSKI v. AMERICAN AIRLINES             9675
tion by Air, commonly known as the “Warsaw Convention.”
Oct. 12, 1929, 49 Stat. 3000, T.S. No. 876 (1934). The Con-
vention provides uniformity with respect to documentation
and certain procedural matters, and imposes limitations on lia-
bility. El Al Israel Airlines, Ltd. v. Tseng, 525 U.S. 155, 169
(1999); In re Aircrash in Bali, Indonesia on April 22, 1974,
684 F.2d 1301, 1307 (9th Cir. 1982). The “recovery for a per-
sonal injury suffered on board an aircraft or in the course of
any of the operations of embarking or disembarking [an air-
craft], if not allowed under the Convention, is not available at
all.” Tseng, 525 U.S. at 161 (quotation and citation omitted).

   [1] Article 17 governs injury to persons suffered during
international air travel and provides:

    The carrier shall be liable for damage sustained in
    the event of the death or wounding of a passenger or
    any other bodily injury suffered by a passenger, if
    the accident which caused the damage so sustained
    took place on board the aircraft or in the course of
    any of the operations of embarking or disembarking.

Warsaw Convention, Art. 17.

   [2] The Convention itself does not define “accident,” but
the Supreme Court did in Air France v. Saks, 470 U.S. 392
(1985). An “accident” is an “unexpected or unusual event or
happening that is external to the passenger.” Id. at 405.
Although “[t]his definition should be flexibly applied after
assessment of all the circumstances surrounding a passenger’s
injuries,” id., “when the injury indisputably results from the
passenger’s own internal reaction to the usual, normal, and
expected operation of the aircraft, it has not been caused by
an accident, and Article 17 . . . cannot apply,” id. at 406. In
turn, the Court focused on the meaning of “event” in Olympic
Airways v. Husain, 540 U.S. 644 (2004). There, a passenger
and his wife were seated near the smoking section. The pas-
senger had a history of anaphylactic reactions to smoke and
9676           TWARDOWSKI v. AMERICAN AIRLINES
asked a flight attendant to be moved away from it. The crew
refused the request, and the passenger died in an apparent
reaction to the smoke in flight. Even though the conduct
amounted to inaction, the Court concluded that it could never-
theless be an “event” because “[t]he rejection of an explicit
request for assistance would be an ‘event’ or ‘happening’
under the ordinary and usual definitions of these terms.” Id.
at 655.

   [3] Based largely on this rationale, passengers here contend
that it was equally unexpected and unusual for air carriers not
to warn effectively about DVT because the airlines had been
“requested” to do so by IATA, the English House of Lords,
and airline doctors. However, an airline’s failure to warn a
passenger about DVT is not an “event,” and thus not an Arti-
cle 17 “accident.” Caman, 455 F.3d at 1092. It does not
become one simply because public agencies have recom-
mended, or “requested,” warnings.

   Other courts, including those of signatory nations whose
views are entitled to weight, are in accord. See, e.g., Blansett
v. Continental Airlines, Inc., 379 F.3d 177, 180 (5th Cir.
2004) (acknowledging that the IATA has recommended that
airlines implement a schedule of instructions on the risks of
DVT, and holding that Continental’s failure to warn of DVT
was not an “unusual or unexpected event” and therefore not
a qualifying “accident”); Povey v. Qantas Airways Ltd.,
(2005) 223 C.L.R. 189 (Austl.) (holding that the failure to
warn of DVT is not an actionable “accident” under the Con-
vention); Deep Vein Thrombosis and Air Travel Group Litig.,
[2005] UKHL 72, [2006] 1 A.C. 495 (U.K.) (same). Nor does
the Federal Aviation Administration require warnings on
DVT.

   [4] Passengers’ reliance on McCaskey v. Continental Air-
lines, Inc., 159 F. Supp. 2d 562 (S.D. Tex. 2001), and Fulop
v. Malev Hungarian Airlines, 175 F. Supp. 2d 651 (S.D.N.Y.
2001), is misplaced. Unlike in Caman, Rodriguez, and Blan-
               TWARDOWSKI v. AMERICAN AIRLINES               9677
sett, injuries in both these cases (as in Hussain) stemmed from
specific health-based requests for help that were unheeded by
airline crew. The passenger in Fulop had a heart attack on
board, 175 F. Supp. 2d at 664; in McCaskey, a stroke, 159 F.
Supp. 2d 568; yet in neither case did the plane divert. Gener-
alized requests by public agencies to warn are quite different
from the particularized requests by individual passengers for
assistance, and the airline’s response to them, at issue in these
cases. Nor does our decision in Prescod v. AMR, Inc., 383
F.3d 861 (9th Cir. 2004), support passengers’ submission that
a “promise” by air carriers to make passenger safety a priority
is an “event.” There, an embarking passenger made a specific
request — that a bag with medications and a breathing device
stay with her on the flights ahead — and the airline gave its
word to honor this request. The airline then unexpectedly
seized, and delayed, the bag. We concluded that seizing the
bag was an “unusual and unexpected event” because doing so
was contrary to the airline’s specific promise, and was exter-
nal to the passenger for the same reason the refusal of assis-
tance in Husain was external to the passenger. Prescod, 383
F.3d at 868. A failure to follow through on a promise to take
care of a specific, health-related request, which was unex-
pected in Prescod because of the promise, does not mean that
every injury to a passenger is an unexpected “event” simply
because airlines have declared that avoiding injury to passen-
gers is a priority.

   Just as we found it unnecessary to decide how industry
standards figure into the Article 17 analysis in Caman, it is
unnecessary to do so here. Passengers present no substantial
evidence of an industry standard with respect to warning
about the risks of DVT.

   Finally, to the extent that passengers fault the district court
for having invoked Article 17’s space and temporal limita-
tions, it was in response to their alternative position that the
airlines “elected” or decided not to warn despite requests to
do so. However, we cannot see how it matters whether, or
9678              TWARDOWSKI v. AMERICAN AIRLINES
when, a decision not to warn was made in this case as there
was no duty to warn of DVT risks in any event.

                                      III

   Passengers submit that regardless of how we view their
case as to others, the judgment must be reversed as to Singa-
pore Airlines because Singapore violated its own safety pol-
icy. Passengers’ only submission in support is a newspaper
article, which is hearsay. As there is no substantial evidence
of Singapore’s policy, we need not (and do not) decide what
effect, if any, an airline’s violation of its own policies would
have on liability under Article 17.

                                      IV

   [5] Passengers maintain that such DVT warnings as were
given through videos, magazines, and in ticket packets, failed
to notify them of the risks of DVT. This is beside the point,
given our holding in Caman that the airlines have no duty to
warn of the risks of DVT. Given no duty to warn, it follows
that there is no duty to warn in any particular way.2

                                      V

   Yesmin A. Canterbury’s argument that summary judgment
should be reversed on the ground that her declaration indi-
cates that a US Airways flight attendant prevented her from
standing and moving around during flight, even if properly
raised in the district court, lacks merit. There was nothing
unusual or unexpected about this flight attendant’s instruc-
tions to Canterbury to remain seated, so this occurrence can-
not constitute an Article 17 accident. See Witty v. Delta Air
  2
   As the Court made clear in Saks, whether there is an “accident” for
purposes of Article 17 is different from the question whether an air carrier
has done all it can to prevent an injury that is inherent in air travel for pur-
poses of Article 20(1). 470 U.S. at 407.
               TWARDOWSKI v. AMERICAN AIRLINES              9679
Lines, Inc., 366 F.3d 380, 385 (5th Cir. 2004) (“[A]ny warn-
ing that passengers should not stay in their seats, but should
instead move about to prevent DVT, would necessarily con-
flict with any federal determination that, all things considered,
passengers are safer in their seats.”).

                               VI

   Passengers’ argument that additional discovery would have
disclosed additional refused requests and disregarded state-
ments establishing the necessity to warn of DVT, and that
failure to do so was part of a cover-up of DVT risk, fails for
essentially the same reasons. The district court permitted
broad discovery into the airlines’ actual practices, warnings of
the risks of DVT, and policies. Beyond this, discovery would
be unlikely to produce any probative evidence.

  AFFIRMED.
