In the
 United States Court of Appeals
              For the Seventh Circuit
                         ____________

No. 06-3773
JOHN MESMAN and JUDY MESMAN,
                                            Plaintiffs-Appellants,
                                v.

CRANE PRO SERVICES, a division of KONECRANES, INC.,
                                             Defendant-Appellee.
                         ____________
             Appeal from the United States District Court
      for the Northern District of Indiana, Hammond Division.
         No. 2:99 CV 428—Paul R. Cherry, Magistrate Judge.
                         ____________
    ARGUED SEPTEMBER 5, 2007—DECIDED JANUARY 2, 2008
                         ____________


  Before POSNER, RIPPLE, and ROVNER, Circuit Judges.
   POSNER, Circuit Judge. This products-liability case is
before us for the second time. 

(7th Cir. 2005).
Federal jurisdiction is based on diversity of citizenship,
and the tort issues are governed by Indiana’s products-
liability statute and its common law of torts. John Mesman,
an employee of a manufacturer of steel products named
Infra-Metals, was gravely injured when a load of steel
sheets that he was unloading from a boxcar fell on him
from the crane that was lifting the sheets out of the boxcar.
He brought suit under the products-liability law against
2                                              No. 06-3773

the firm that had rebuilt the crane, Konecranes. A jury
awarded the plaintiffs (Mesman and his wife) $5.6 million,
based on its judgment that Konecranes was one-third
responsible for the accident and Infra-Metals—which
Mesman could not join in the suit because it was his
employer—two-thirds responsible. But the judge set the
verdict aside and entered judgment for the defendant. She
further ruled that if she was wrong in doing this the
defendant was entitled to a new trial because the jury had
been confused by irrelevant evidence and had ignored
critical instructions. We reversed the judgment for the
defendant but affirmed the order for a new trial. The
case was retried and this time the jury returned a verdict
for the defendant. The magistrate judge presiding at the
retrial refused to set the verdict aside. Hence this sec-
ond appeal, which is by the plaintiffs.
  The crane that was the instrumentality of the accident
consisted of the following parts: a beam fastened to the
ceiling directly above a rail siding; a hoist, suspended
from the beam, which the crane’s operator could move
sideways along the beam, as well as up and down to do
the lifting; another beam, the “spreader beam,” connected
to the hoist; chains connecting each end of the spreader
beam to “scoops” for gripping the load; and, attached to
the beam on the ceiling, an operator’s cab. When a box-
car was unloaded underneath the section of the ceiling
beam to which the cab was attached, there was only a
foot or two of clearance between the rim of the boxcar
and the cab. If while being lifted by the hoist the spreader
beam struck the cab, the load might be jarred loose and
fall, hitting anyone beneath it.
 Infra-Metals hired Konecranes to rebuild the crane,
which was nearly 50 years old. Konecranes was to supple-
No. 06-3773                                              3

ment the controls in the operator’s cab with a hand-held
remote-control device that would enable the crane to be
operated from ground level. To raise the load the operator
would press the up button on the remote and to lower it
he would press the down button. Alongside those but-
tons was an emergency-stop button so that if the
operator sensed an impending collision between the
load and the cab he could bring the hoist and spreader
beam to a dead stop. Alternatively, by pressing the down
button he could reverse the direction of the hoist; but
because the up and down control had a deceleration
feature to reduce wear and tear on the crane, the hoist and
therefore the spreader beam would continue to rise for
as many as three seconds (if the crane was being operated
at its top speed) after the down button was pressed. In
that interval the hoist would traverse about a foot until
it stopped and began its downward motion; so pressing
the down button would not arrest the upward motion
of the hoist as fast as pressing the emergency-stop button
would.
  Konecranes also built into the renovated crane a limit
switch that would automatically stop the spreader beam
when it came too near the beam in the ceiling. But the
switch was set to prevent the spreader from touching
that beam only when the cab, the floor of which was of
course lower than the beam from which the cab hung,
was not over the spreader. To prevent the spreader from
touching the cab when it was underneath it, the limit
would have had to be set much lower—too low for con-
venient unloading of boxcars that were underneath any
other section of the beam. Thus, as set, the limit switch
did nothing to prevent a collision between the load and
the cab.
4                                              No. 06-3773

  On the day of the accident, the employee of Infra-Metals
who operated the crane was standing at ground level
about 20 feet away from a boxcar that was underneath
the cab. Mesman, standing in the boxcar, fastened a load
of steel sheets to the scoops beneath the spreader beam.
The operator pressed the up button on the remote. As
the beam and load rose, he saw that the spreader beam
was going to hit the cab. But instead of pressing the emer-
gency-stop button, as he should have done to bring the
rising load to a dead stop, he pressed the down button.
Because of the deceleration feature, the spreader beam
continued to rise for three seconds, hitting the cab and
causing the load to fall on Mesman.
  Had Konecranes, when it renovated the crane, removed
the cab, eliminated the deceleration feature, or modified
the limit switch so that the limit could be lowered when
a load was being unloaded beneath the cab, the accident
would have been avoided: with certainty in the case of
either of the first two modifications but less certainly in
the case of the third modification—making the limit
switch adjustable—since the operator might neglect to
adjust it. So a better safety device would have been an
electronic eye or other electronic sensor that would have
stopped the hoist automatically when the spreader beam
was dangerously close to the underside of the cab. Such
a device would have been proof against human error or
inattention. But the parties have not discussed that possi-
bility.
  The Indiana Products Liability Act makes a design defect
actionable only if there is negligence in the design. Ind.
Code § 34-20-2-2. The risk of a heavy load falling on
a worker if the spreader beam struck the cab was sub-
stantial because of the narrow clearance, and if the load
No. 06-3773                                                  5

did fall on someone it would be likely to kill or seriously
injure him. Loads did fall, especially when cold weather
made the steel sheets being unloaded slippery and there-
fore more likely to slide out of the scoops. The part of the
plant where the sheets were unloaded from rail cars
was open to the elements, and the accident to Mesman
occurred on a very cold winter day. One or two loads
had already fallen that day before the accident, though no
one had been hurt.
   But in a negligence case the risk of injury has to be
weighed against the cost of averting it. In Judge Learned
Hand’s negligence formula, failure to take a precaution
is negligent only if the cost of the precaution (what
Judge Hand called the “burden” of avoiding the accident)
is less than the probability of the accident that the precau-
tion would have prevented multiplied by the loss that
the accident if it occurred would cause. United States v.
Carroll Towing Co., 

, 173 (2d Cir. 1947) (i.e., B <
PL). In other words, the cheaper the precaution, the
greater the risk of accident; likewise, the greater the
harm caused by the accident, the likelier it is that the
failure to take the precaution was negligent.
  The risk could have been eliminated by removing the
cab, which was no longer required for the operation of
the crane. Konecranes recommended that to Infra-Metals
but Infra-Metals declined because it wanted the option of
being able to operate the crane from within the cab.
Alternative precautions, besides making the limit switch
adjustable, would have included eliminating the decelera-
tion feature on the remote control, so that pressing the
down button while the spreader beam was rising
would have brought the hoist to an immediate stop. But
this would not have been an ideal solution either, be-
6                                               No. 06-3773

cause without the deceleration feature the crane would
wear out sooner. The same drawback would have at-
tended another precaution—reducing the period of decel-
eration from three seconds to one, which would have
stopped the spreader beam within four inches after the
down button was pressed rather than twelve. Still another
possibility would have been an additional automatic
limit switch, one operative only when the unloading
was taking place directly under the cab. And another
might have been the “idiot proof” safety device that the
parties do not discuss.
  The only really contestable issue in the case, we said
in our first opinion, was whether any precaution was
necessary besides the emergency-stop button, since, had
the operator pressed it instead of the down button, the
accident would not have occurred. Konecranes argued
that by pressing the down button the operator had ex-
posed Mesman to a danger that was “open and obvious”
to the operator, and that a defendant should not be liable
for accidents resulting from open and obvious dangers.
But while it indeed used to be the law that manufacturers
had no obligation to protect against “open and obvious”
dangers, Indiana has replaced the “open and obvious”
defense with a defense (“incurred risk”) that requires that
the user of the product (in this case the operator of the
crane) have actually been “aware of the danger in the
product.” Ind. Code § 34-20-6-3. The fact that a risk is open
and obvious remains relevant to liability. It is circumstan-
tial evidence that the user knew of the danger and thus
“incurred” the risk. But it also bears on the question
whether the risk was great enough to warrant protective
measures beyond what the user himself could be expected
to take. Suppose a machine is designed with no shield over
No. 06-3773                                                7

its moving parts. It is obvious to the operator that if he
sticks his hand into the machine while it is operating, the
hand will be mangled. In the old days that would have
been a complete defense to a suit for products liability. But
the Indiana statute recognizes that because of inadvertence
or other human error, or because of debris or a slippery
surface that might cause a worker to trip, or even because
of a distracting noise or a sudden seizure, open and
obvious hazards do on occasion result in accidents that are
not the product of a known risk, obvious though the risk is.
If such an accident can easily be avoided by the taking of a
precaution by the manufacturer of the machine or by the
operator’s employer, it should be, and liability provides a
prod to adopt the precaution.
  Was there so great a likelihood that the operator of
the rebuilt crane would fail to press the emergency-stop
button when he saw the spreader beam about to hit the
cab that Konecranes should have modified the control?
The likelihood that the operator would push the wrong
button in an emergency, or forget that pushing the down
button wasn’t as effective as pushing the emergency-
stop button because of the deceleration feature, was
surely not negligible, and so argued for an automatic
protective device, of which probably the cheapest
would have been to remove the cab. A jury that con-
cluded that, all things considered, the failure to design
the renovated crane in such a way as to protect Mesman
against the kind of error that the crane’s operator made
was negligent could not be thought unreasonable. The
entry of judgment for Konecranes in the first trial, over-
riding the jury’s verdict for Mesman, was therefore error.
  But we affirmed the judge’s decision granting
Konecranes a new trial because Mesman’s lawyer had
failed to put before the jury a clear picture of the cause
8                                               No. 06-3773

of the accident and how it might have been prevented.
His principal expert witness, an engineer, had not
bothered even to visit Infra-Metals’ plant, and the evid-
ence regarding the clearance between the boxcar and the
cab had been hazy even though the meagerness of the
clearance was the key fact in the case. A “human factors”
analyst wasted the jury’s time trying to show that the
remote should have been made to operate by means of
a joystick rather than pushbuttons. The joystick wouldn’t
have altered the deceleration feature, and there was no
reason to think that the crane’s operator would be less
likely to press the emergency-stop button than to move
a joystick.
  The retrial was much like the first trial, except that
Konecranes was permitted to argue that it could not be
responsible under the Indiana Products Liability Act for
the dangerous location of the cab because it had not
manufactured the crane (of which the cab was a com-
ponent) but had merely repaired it. The argument
should not have been permitted. It is true that the Act
does not apply to a repair, but it does apply to a rebuild-
ing—a well-established distinction in products-liability
law, e.g., Lenhardt Tool & Die Co. v. Lumpe, 

,
1085 (Ind. App. 1998); Richardson v. Gallo Equipment Co., 

(7th Cir. 1993) (Indiana law)—for, if it did not
apply, there would be an inefficient incentive to rebuild
an old product rather than make a new one. Konecranes
rebuilt the crane, altering its design to enable it to be
operated from ground level rather than just from the
overhead cab.
  But the error in allowing the jury to speculate on how
far Konecranes’ decision to rebuild was subject to the
products liability act was inconsequential, because the
No. 06-3773                                               9

plaintiffs were permitted to claim common law negli-
gence, as they had not previously bothered to do. There is
no difference, except possibly with respect to the “open
and obvious” defense, that is material to this case between
common law negligence and negligence under the products
liability statute; and we shall see that the “open and
obvious” defense turned out not to play a significant
role in the second trial.
  Mesman complains about the magistrate judge’s refusal
to instruct the jury on the Learned Hand negligence
formula. This could not be an error, because the judge
gave the standard Indiana pattern instruction on negli-
gence, a correct statement of Indiana law that a federal
court in a diversity suit is bound by. In any event, the
instruction the plaintiffs wanted the judge to give was
not the Hand formula, but a garbled version of it: “If
you find that in renovating the crane the defendant
failed to take effective precautions less expensive than the
damages which could reasonably be expected to result
from the crane’s foreseeable use or misuse, then you may
find the defendant negligent. Even if you determine
that the particular failure which occurred was not likely
to occur, you may still find the defendant liable if the
costs of preventing the harm were lower than the costs of
a reasonably foreseeable injury.” The Hand formula
requires, as we have seen, discounting (multiplying)
the harm if an accident should occur by the probability
that it would occur unless a precaution were taken,
and then comparing the product of that multiplication to
the cost of the precaution. Thus, if the harm from the
accident would be very great and the cost of preventing it
very low, the defendant might be negligent even if the
probability of the accident was also low. That may be
10                                                 No. 06-3773

this case. Suppose the probability (P in Hand’s formula)
were .001, the loss if the accident occurred (L) $1 million,
and the cost of avoiding the accident (B, for burden of
precaution) $500. Then because $500 is less than $1 million
× .001 (=$1,000), the injurer would be adjudged negligent.
(The numbers in the example are merely illustrative,
of course.) But this was not what the proposed instruc-
tion would have directed the jury to consider.
   The failure to give the garbled instruction cannot have
been a plain error since it was not an error at all; and it
would have had to be a plain error to get the plaintiffs a
new trial, since their lawyer failed to object to the judge’s
refusal to give the instruction. (That he failed to object
is conceded, though there is no record of the instructions
conference because the magistrate judge unwisely con-
ducted it off the record. Cf. Fed. R. Civ. P. 51(b)(2), (c)(1);
Maltby v. Winston, 

, 560-61 (7th Cir. 1994).)
Moreover, while a plain error even in instructions in a
civil case is now a basis for reversal, Fed. R. Civ. P. 51(d)(2);
Higbee v. Sentry Ins. Co., 

, 409 (7th Cir. 2006),
reversal is not automatic; it is in the discretion of
the reviewing court, as the Supreme Court made clear
in United States v. Olano, 

, 735 (1993). That was
a criminal case, but it provides guidance to the inter-
pretation of the civil plain error rule, which was taken
verbatim from the criminal rule a decade after the Olano
decision. Compare Fed. R. Civ. P. 51(d)(2) with Fed. R.
Crim. P. 51(b). Olano teaches that a plain error must be
corrected if it resulted in a miscarriage of 

, and we may assume that the same principle
governs civil plain error. But Mesman’s case is not so
strong that we can say that had it not been for an er-
roneous instruction he would surely have prevailed at
No. 06-3773                                               11

trial. The Committee Notes to the 2003 Amendments to
Fed. R. Civ. P. 51 that added the provision on plain
error mentions “the costs of correcting an error” as a factor
for the judge to consider in making his discretionary
decision whether to reverse on the basis of a plain error,
and that is an important factor in this case. In the ab-
sence of extraordinary circumstances, a lawyer should not
be heard to request a third jury trial on the basis of an
instruction (or a failure to instruct) to which he failed to
object.
  The plaintiffs also complain about the magistrate judge’s
refusal to give their proposed instruction on incurred
risk. Since they failed to include in the appendix to their
brief the instruction on incurred risk approved by the
magistrate judge (see United States v. Thomas, 

(7th Cir. 1998) (per curiam)), failed to include a transcript
of the instruction as actually read to the jury, and do not
even tell us what the instruction was, we cannot deter-
mine whether it was inferior to their proposed instruction.
  Another instruction with which the plaintiffs take
issue told the jury that “a manufacturer has no duty to
warn of and is not liable for open and obvious dangers”
(emphasis added). Probably the intended meaning is
that a manufacturer is not liable for failing to warn of an
open and obvious danger rather than that he is not liable
for failing to prevent the danger—an interpretation that
would be squarely contrary to Indiana law. But it is
confusing and shouldn’t have been given. It provides
only a feeble basis for reversal, however, especially as
the plaintiffs have failed to explain how it is likely to
have influenced the jury. The instruction mentions liabil-
ity for open and obvious dangers, and that is the error;
but it foregrounds duty to warn. The plaintiffs had and
12                                              No. 06-3773

took full opportunity to present multiple theories of
liability to the jury, including the joystick theory that
we rejected in our previous opinion. But they had diffi-
culty meeting Konecranes’ effort to shift all responsi-
bility for the accident to Infra-Metals. Konecranes argued
that by recommending that Infra-Metals remove the
cab, which Infra-Metals refused to do, and by offering
training for Infra-Metals’ employees on the new de-
celerator function, which Infra-Metals also declined,
Konecranes had done all it could reasonably be expected
to do and therefore that Infra-Metals bore all the blame
for the accident. For Infra-Metals’ insistence on being
able to operate the crane from the cab could not plausibly
be defended as a safety measure. Placing the control of
the crane at ground level may have made it difficult for
the operator to gauge the distance between the rising
load and the overhead cab. But a person operating the
crane from the cab would also have had a hard time
gauging the distance between the rising load and the
cab. The cab did not have a see-through floor, so the
operator’s visibility would have been horizontal and
diagonal rather than vertical.
  Konecranes had convinced the jury in the first trial to
place two-thirds of the blame for the accident on Infra-
Metals; the second jury may have thought three-thirds a
better estimate, thus rejecting the argument that we
have just sketched. Not that such apportionments
always make sense when the issue is liability rather than
contribution among joint tortfeasors. Suppose X could
prevent a grievous accident to Z at a cost (much lower than
the expected accident cost) of $1,000, and Y could prevent
the accident at a cost of $500. We would want Y to take the
precaution rather than X, but if, as arguably in this case, X
No. 06-3773                                                     13

(Konecranes) knows that Y (Infra-Metals) is not planning
to take any precaution, then X should do so, if he cannot
persuade (or pay) Y to take the cheaper one. Bacile v. Parish
of Jefferson, 

, 1090 (La. App. 1981); Taylor v.
Paul O. Abbe, Inc., 

, 148 (3d Cir. 1975) (dictum);
cf. W. Page Keeton et al., Prosser & Keeton on the Law of
Torts § 100, pp. 705-06 (5th ed. 1984). It would be dif-
ferent if, as in Scallan v. Duriron Co., 

, 1254
(5th Cir. 1994), Crossfield v. Quality Control Equipment Co., 

, 704 (8th Cir. 1993), and Childress v. Gresen Mfg.
Co., 

(6th Cir. 1989), X is merely the supplier
of a component and has reason to defer to Y’s, the final
assembler’s, judgment concerning the safety of the final
product. But that is not this case.
  There is an illuminating parallel between the duty
just discussed and the abolition of “open and obvious” as
a complete defense in a personal-injury case. They are
both instances of imposing back-up liability. The worker
confronting a danger that is open and obvious should
avoid it, but as he may not (possibly without fault on his
part—he may have been distracted and as a result was
unaware of the risk), the law, by eliminating the defense
that the danger was open and obvious, imposes a duty
of back-up care on the manufacturer. Similarly, a sup-
plier of a part to an assembler who knows that while his
part is not defective it “will be used in a way that will
m a k e t h e a s s e m b l e d p r od u c t u n r e a s on a b l y
dangerous . . . may well be subjected to liability on a
warranty of fitness theory if the purchaser was relying
on the seller, or a negligent entrustment theory or per-
haps strict liability in tort without regard to reliance.”
Keeton et 

. Products “are often made by
independent contractors from materials furnished by
14                                                No. 06-3773

their employers. In such a case, the contractor is not
required to sit in judgment on the plans and specifica-
tions or the materials provided by his employer. The
contractor is not subject to liability if the specified design
or material turns out to be insufficient to make the chattel
safe for use, unless it is so obviously bad that a competent
contractor would realize that there was a grave chance that his
product would be dangerously unsafe.” Restatement (Second) of
Torts § 404, comment a (1977) (emphasis added); and
see the cases cited in the preceding paragraph. Note
“obviously”; and note how both doctrines we have been
discussing resemble the doctrine of “last clear chance.”
  But the plaintiffs did not argue that Konecranes’ effort
to shift all blame for the accident to Infra-Metals was a
red herring; and so the consideration decisive for our
review of the rulings at trial is that the misleading in-
struction on “open and obvious” cannot have determined
the jury’s verdict. The defendant’s principal argument
was not that the danger was obvious, whether to the
accident victim or to the crane’s operator, but that the
safety precautions were adequate and that the culpable
cause of the accident was Infra-Metals’ failure to instruct
the operator adequately in the safe operation of the
crane. Apparently the jury was persuaded. There are no
grounds for setting aside its verdict. The judgment for
the defendant is therefore
                                                   AFFIRMED.
No. 06-3773                                            15

A true Copy:
       Teste:

                      _____________________________
                      Clerk of the United States Court of
                        Appeals for the Seventh Circuit




                USCA-02-C-0072—1-2-08