dissenting:
On August 8, 1970, Paul Burch was cutting wet grass with a seven year old, electric power mower which had been purchased second hand from a florist. The wet grass became impacted and “choked” the cutting action of the blade. Without turning off the electrical switch and without disconnecting the cord from the electrical supply, Burch turned the mower on its side, reached into the blade area, and began to remove the impacted, wet grass.1 After some of the wet grass had been removed, the blade started again to rotate and in the process cut off several fingers from Burch’s hand. The majority holds that a jury could find that the 1963 mower was designed defectively because a professor of mechanical engineering, who had no experience whatsoever in designing or marketing electrical power mowers, believed the machine would have been safer if it had been equipped with a deadman’s switch. I dissent.
There was no evidence of a manufacturing defect, i.e., an accidental variation caused by a mistake in the manufactur*462ing process. The machine had previously been used for seven years. Burch contended, rather, that the mower, although manufactured in conformity with its intended design, was defective because the design itself created a defective condition unreasonably dangerous to users.
The electric power mower in the instant case was retailed by Sears, Roebuck Co. in 1963 under the tradename “Craftsman.” It had been designed and manufactured by Roper Corporation. General Electric had supplied the electric motor; and Texas Instruments, Inc. had manufactured the manual “on-off” switch which was mounted on the handle of the mower. At the time of the accident, according to the evidence, the original switch was no longer on the machine, having been replaced by another. The machine also contained a thermal shut-off control on the motor and an electrical cord which, when connected, delivered the electricity necessary to energize the lawn mower.
“Unlike workmen’s compensation and no-fault automobile insurance, strict liability is not a no-fault system of compensation.” Thibault v. Sears, Roebuck & Co., 118 N.H. 802, 806, 395 A.2d 843, 845-846 (1978). When courts are confronted with claims of design defects, the issues are usually complex. Design choices are multi-faceted. They must comprehend and consider the various accident situations in which the product may be involved. Design choices must also reflect considerations of marketability, i.e., whether machines such as lawn mowers, with increased safety precautions at necessarily higher prices, are marketable in competition with less expensive machines having fewer safeguards manufactured by others. Consumers willing to assume the risk and who want to be able to buy at lower prices may choose models that do not contain extensive safety precautions with which more expensive models are equipped.
In a design defect case, it must first be shown that there exists a defective condition unreasonably dangerous to the user. A defective condition exists when “the product is, at thé time it leaves the seller’s hands, in a condition not *463contemplated, by the ultimate consumer, which will be unreasonably dangerous to him.” Restatement (Second) of Torts, § 402A, comment g (emphasis supplied). In Cornell Drilling Company v. Ford Motor Company, 241 Pa.Super. 129, 136, 359 A.2d 822, 825 (1976), this Court quoted Pros-ser, Law of Torts, 659 (4th ed. 1971) to state the prevailing view that a product is defective if it “does not meet the reasonable expectations of the ordinary consumer as to its safety.”
The manufacturer of an electric power mower is not an insurer and is under no obligation to make an accident proof product. He is not required to design a mower which will cut nothing but grass. Some products, such as hatchets, carving knives, and power lawn mowers, contain obvious dangers. Manufacturers cannot foresee and protect against every absurd and dangerous use that may be made of a product. They are required to foresee and protect the consumer only from the probable results of the normal use of the product. Sometimes, a warning will be all that is required. Even a warning is unnecessary, however, where the danger is obvious. Thus, there is no need to warn that a knife will cut. Consumers, themselves, have a responsibility to guard against obvious dangers in the use of a product.
Inquiry into the design of a product must also consider social utility. “The utility of the product must be evaluated from the point of view of the public as a whole, because a finding of liability for defective design could result in the removal of an entire product line from the market. Some products are so important that a manufacturer may avoid liability as a matter of law if he has given proper warnings.” Thibault v. Sears, Roebuck & Co., supra, 118 N.H. at 807, 395 A.2d at 846.
Perhaps the most important evidence in a defective design case is evidence of the state of the art at the time a product is manufactured. This helps to determine the expectation of the ordinary consumer. Bruce v. Martin-Marietta Corp., 544 F.2d 442 (10th Cir.1976). Relevant to show *464the state of the art are industry design standards, design guidelines adopted by authoritative voluntary associations, and design criteria established by legislation or regulations of administrative agencies. See: Owens v. Allis-Chalmers Corp., 83 Mich.App. 74, 268 N.W.2d 291 (1978), aff'd, 414 Mich. 413, 326 N.W.2d 372 (1982); Hubbard v. McDonough Power Equipment, Inc., 83 Ill.App.3d 272, 38 Ill.Dec. 887, 404 N.E.2d 311 (1980). See also and compare: Meyer v. Heilman, 307 Pa.Super. 184, 188, 452 A.2d 1376, 1378 (1982), allocatur granted March 29, 1983 (evidence that competitors’ tractors of a similar vintage were designed with a safety device which would have prevented injury).
The design engineer who had designed the Craftsman electrical power mower in this case testified and produced evidence which established that the foregoing factors had been considered prior to manufacture. Studies conducted by the manufacturer showed that a machine containing a manual, “on-off” switch was not only less expensive and more desirable to consumers but also safer to use than one containing a deadman’s switch. Electric power mowers containing deadman’s switches were less maneuverable and resulted in frequent cuttings of the cord. They were more hazardous, studies showed, because of the ease with which inadvertent startings occurred and also because of the tendency of consumers to tie or wire the switch into an “on” position to avoid the necessity for constant pressure on the switch while the mower was in use. Appellee relied upon the testimony of a professor of mechanical engineering, who had had no experience in designing, manufacturing or marketing electrical or other power mowers and who had not examined the offending machine until four years after the accident. This witness was not aware of industry standards and regulations in 1963, if any existed, and was not privy to information then available to and relied upon by designers of electric power mowers. He testified that dead-man’s switches were available in 1963—a fact which all defendants conceded—and that they were relatively inexpensive. He was permitted to testify, over objection, that in his opinion the electrical power mower designed in 1963 *465should have been equipped with a deadman’s switch because it would have rendered the machine safer and would have prevented the accident which injured Paul Burch. He offered no design criteria or applicable design standards that would have enabled the court or jury to determine objectively that the manufacturer had breached a duty to consumers generally by putting on the market a defectively designed lawn mower. He could not say that deadman’s switches were in widespread use on similar electric mowers manufactured by others in 1963.
Who determines whether the absence of a deadman’s switch on a 1963 electric power mower has rendered the machine defective for purposes of imposing strict liability upon the manufacturer? The Supreme Court asked a similar question in Azzarello v. Black Brothers Company, Inc., 480 Pa. 547, 391 A.2d 1020 (1978). Its concern was contained in its observation that “[wjhile a lay finder of fact is obviously competent in resolving a dispute as to the condition of a product, an entirely different question is presented where a decision as to whether that condition justifies placing liability upon the supplier must be made.” Id., 480 Pa. at 556, 391 A.2d at 1025 (footnote omitted). This question, the Court concluded, did not fall within the orbit of a factual dispute which could properly be left to the jury for resolution. The Court said:
“Should an ill-conceived design which exposes the user to the risk of harm entitle one injured by the product to recover? Should adequate warnings of the dangerous propensities of an article insulate one who suffers injuries from those propensities? When does the utility of a product outweigh the unavoidable danger it may pose? These are questions of law and their resolution depends upon social policy. Restated, the phrases ‘defective condition’ and ‘unreasonably dangerous’ as used in the Restatement formulation are terms of art invoked when strict liability is appropriate. It is a judicial function to decide whether, under plaintiff’s averment of the facts, recovery would be justified; and only after this judicial determination is made is the cause submitted to the jury *466to determine whether the facts of the case support the averments of the complaint. They do not fall within the orbit of a factual dispute which is properly assigned to the jury for resolution.”
Id., 480 Pa. at 558, 391 A.2d at 1026. See also: Green, Foreseeability in Negligence. Law, 61 Columbia L.Rev. 1401, 1418 (1961); Dambacher v. Mallis, Pa.Super. (J. 1725/82; filed June 17, 1983) (Dissenting Opinion by Spaeth, J.).2 Spaeth, J.).2
The trial court did not make a determination of strict liability in this case but submitted it to the jury to determine whether strict liability should attach to a 1963 electric mower marketed without a deadman’s switch. This, according to my understanding of Azzarello, was error.
Whether strict liability is appropriate in this case is a judicial decision. The record in the case discloses no criteria that would enable either a court or jury to determine that the manufacturer had designed and marketed a defective and unduly hazardous machine. In the absence of legislative or other extra-judicial criteria for determining that a product has been defectively designed so as to be unreasonably dangerous, “the manufacturer of a machine ... dangerous because of the way in which it functions, and patently so, owes to those who use it a duty merely to make it free from latent defects and concealed dangers.” Myers v. Montgomery Ward & Co., Inc., 253 Md. 282, 294, 252 A.2d 855, 863 (1969), quoting from Kientz v. Carlton, 245 N.C. 236, 241, 96 S.E.2d 14, 18 (1957). See also: Denton v. Bachtold Brothers, Inc., 8 Ill.App.3d 1038, 291 N.E.2d 229 (1972); Restatement (Second) of Torts, § 402A, comment g. Compare: Clark v. Sears, Roebuck and Company, 254 So.2d 62 (La.App.1971). See generally: Annotation, Liability of Manufacturer or Seller of Power Lawnmower For Injuries to User, 41 A.L.R.3d 986 (1972). When marketed, the electric power mower in this case contained no latent defects or concealed dangers. I would hold, therefore, that strict liability was not appropriate. After studying the *467evidence pertaining to the “state of the art” in 1963, the total lack of extra-judicial standards or guidelines requiring deadman’s switches on electric power mowers (as distinguished from riding mowers), and the results of market studies made by the manufacturer, which were unrebutted, I would hold that an electric power mower designed with an electric cord and an “on-off” switch was neither “defectively designed” nor “unreasonably dangerous.” See: Myers v. Montgomery Ward & Co., supra; Kientz v. Carlton, supra. See also: 41 A.L.R.3d 986.
In Owens v. Allis-Chalmers Corp., 414 Mich. 413, 326 N.W.2d 372 (1982), a design defect case raising issues similar to those in the instant case, the plaintiff sought to establish that a forklift had been defectively designed because of the absence of restraints which would have prevented the operator from being thrown from the operator’s compartment if the forklift rolled over. The plaintiff’s expert witness was a physicist who had worked for General Motors for twelve years in the area of vehicle safety. He testified that the forklift would have been safer in view of the manner in which the accident happened if it had been equipped with a seat belt or other restraint system. The expert, however, “had never designed a forklift, nor any part of one, and had not worked in conjunction with their manufacture. He had operated one during a summer about 30 years prior to trial, but not since. Apart from preparing for this litigation, the record [was] not clear concerning whether any of his work in the area of vehicle safety had related specifically to forklifts. He testified, however, that a forklift was just another type of vehicle to which much of his work on vehicles in general would be applicable.” Id. at 418, 326 N.W.2d at 374. The expert witness admitted also that he was not aware of any law, safety regulation, standard or policy that required or suggested the use of restraints, and that he was unaware of any forklift manufactured with restraints. The defendant moved for a directed verdict on the grounds that the record lacked any basis for the expert’s assertion that restraints were needed, and that the expert’s unsubstantiated opinion was insufficient to *468establish a prima facie case. The trial court granted the defendant’s motion. The Supreme Court, after demonstrating obvious concern about the troublesome issue of holding a product defective merely because of a failure to equip it with all possible safety devices, affirmed. The testimony of plaintiff’s expert was insufficient, without evidence of other design criteria available to the manufacturer, to warrant submitting the issue to a jury. The court said:
“Our conclusion that the plaintiff did not present a prima facie case is based on the lack of evidence concerning both the magnitude of the risks involved and the reasonableness of the proposed alternative design. Although from the testimony of plaintiff’s expert one might infer that a forklift rollover and the injuries resulting from being pinned under the overhead protective guard were foreseeable, neither his testimony nor any other evidence on the record gave any indication how likely such an event might be. In conjunction with this uncertainty, the record also produces no indication how the use of any of the driver restraints would affect a forklift operator’s ability to do his or her job or the operator’s safety in other circumstances.
Viewing the evidence in a light most favorable to the plaintiff, we cannot conclude that plaintiff established a prima facie case for either negligence or a defective product. Even if this Court could take judicial notice that the costs involved in attaching a seat belt or other designated restraint to a forklift would not be great, we cannot take judicial notice that their use by forklift drivers would be likely, practical, or more safe. Neither the costs nor the effects of the other restraints were established.
Significantly, the defendant did offer the cage enclosure, which was one of the suggested restraints, as an option. The question then becomes whether such a cage enclosure should have been installed as standard equipment. Although plaintiff’s expert acknowledged that some drivers are frequently in and out of their vehicles, there was no testimony concerning the effects of a cage *469upon the driver’s ability to perform his or her work. There also was no factual testimony concerning the safety of an operator in a cage enclosure in a roll-over or in any foreseeable accidents or emergencies other than rollovers ____
In the entirety of plaintiff’s proofs, there is no data or other factual evidence concerning the magnitude of the risks involved, the utility or relative safety of the proposed alternatives, or evidence otherwise concerning the ‘unreasonableness’ of risks arising from failure to install driver restraints on the subject forklift model as standard equipment.
Manufacturers are not insurers that ‘in every instance and under all circumstances no injury will result from the use’ of their products. E.I. DuPont de Nemours & Co. v. Baridon, 73 F.2d 26 (CA 8, 1934).
Therefore, we find that the trial court did not err. The plaintiff’s evidence did not raise an issue of fact concerning any unreasonable risk at the time of the design or manufacture of the vehicle.”
Id. at 429-432, 326 N.W.2d at 378-379.
The majority says that “[sjeveral courts have held that the lack of a deadman’s switch, that would automatically turn off machinery when a user relaxes his grip on the controls, presents a jury question of a lawn mower’s defective design.” This is misleading. The cases cited by the majority did not involve electric power mowers comparable to the mower in the instant case. They involved riding mowers. Baker v. Outboard Marine Corp., 595 F.2d 176 (3rd Cir.1979) (plaintiff alleged that riding mower was defectively designed as a result of, inter alia, absence of deadman’s switch which would stop mower when operator left the seat); Daniels v. McDonough Power Equipment, Inc., 430 F.Supp. 1203 (S.D.Miss.1977) (plaintiff alleged that riding mower was defectively designed due to lack of device to automatically disengage wheels and/or blades when operator was removed from seat); Schurr v. Royal Globe Insurance Co., 353 So.2d 215 (Fla.App. 1977) (plaintiff alleged that riding lawn mower was defectively designed due *470to absence of deadman’s switch); Hubbard v. McDonough Power Equipment, Inc., supra (1980) (plaintiff alleged that riding lawn mower was defectively designed because it was dynamically unstable and lacked a deadman’s switch). There is a substantial difference between riding mowers and manually operated mowers in which only the blades are powered electrically. Riding mowers, if not equipped with a deadman’s switch, will move forward eccentrically with blades rotating and substantial risk when not subject to the operator’s control. An electric mower of the type here involved moves forward only when physically pushed or pulled by the operator. If the operator loses control, the motion of the machine ceases as soon as he loosens his grip. Although the blade continues to rotate, the machine is stationary. The risks inherent in the two types of machines are vastly different and their designs entail different considerations.
In the instant case, moreover, Burch’s placing his hand into the blade area of this electric lawn mower to remove impacted grass without disconnecting the machine from the electric supply, either by removing the cord from the outlet or by using the “on-off” switch, was so unusual and so abnormal that the manufacturer could not be expected to protect Burch from his own conduct. See and compare: Bartkewich v. Billinger, 432 Pa. 351, 247 A.2d 603 (1968).
If, as the majority and at least one federal court decision3 seem to imply, the language of Azzarello is not to be followed literally and the defectiveness of the design of a power lawn mower which conceivably could have been equipped with additional safety features is for the jury, I should hold, nevertheless, that a new trial is required in this case. I should conclude that plaintiff’s expert was unqualified to express an opinion concerning the design of this electric lawn mower in 1963 and that, in any event, the verdict was contrary to the clear weight of the evidence.
“An expert witness has been defined as a person who possesses knowledge not within the ordinary reach and *471who, because of this knowledge is specially qualified to speak upon a particular subject.” Erschen v. Pennsylvania Independent Oil Company, 259 Pa.Super. 474, 477, 393 A.2d 924, 926 (1978). As a general rule, the qualification of an expert witness is a matter within the discretion of the trial court. Abbott v. Steel City Piping Company, 437 Pa. 412, 421, 263 A.2d 881, 885 (1970); Duffy v. National Janitorial Services, Inc., 429 Pa. 334, 338, 240 A.2d 527, 529 (1968). An expert witness cannot be found qualified to express an opinion regarding matters beyond the ken of the average layperson, however, unless the witness has “sufficient skill, knowledge or experience in that field or calling to make it appear that his opinion or inference will probably aid the trier in his search for truth.” McCormick on Evidence, p. 30 (2d ed. 1972). This requires that the witness demonstrate “special knowledge of the very question upon which he promises to express his opinion.” Jones Appeal, 449 Pa. 543, 551 n. 5, 297 A.2d 117, 121 n. 5 (1972); Sweeney v. Blue Anchor Beverage Co., 325 Pa. 216, 189 A. 331 (1937).4
In the instant case, appellee’s expert failed to possess the special knowledge necessary to express an opinion pertaining to the design of an electric lawn mower in 1963. His qualifications were limited to the fact that he held a Ph.D. in mechanical engineering and had taught engineering at several universities. His degree in mechanical engineering, I suggest, is not an adequate basis upon which to permit expression of an opinion regarding the design criteria available and applicable to the design of electric lawn mowers in 1963. The design and marketing of power mowers are not matters within the expertise or experience of each and *472every engineer. One needs specific knowledge, training, or experience to express an opinion on safety criteria available for use in designing and marketing power lawn mowers. Appellee’s expert had no such knowledge, training or experience. He had never studied, designed, marketed or even repaired an electric lawn mower and had never consulted with or worked for anyone who did. He did not pretend to know or understand the market for lawn mowers in 1963 and was unaware of safety standards, governmental regulations or design criteria then applicable. He had never participated in consumer testing of lawn mowers, and had never tested a lawn mower until he examined the lawn mower in this case four years after the accident. In short, there was no evidence that he had ever had any experience of any kind, direct or indirect, in the design or even use of electric or others type of power lawn mowers. Under these circumstances, his degree and academic background in mechanical engineering were insufficient to demonstrate that special knowledge or experience which would enable him to provide meaningful opinion evidence relevant to the complex and multi-faceted issue of the design of electric power mowers in 1963. To permit him to express an expert opinion on this issue, in view of the lack of his qualifications to do so, was reversible error.
Assuming for purposes of argument that a jury could consider his opinion testimony, I would hold that the verdict was against the weight of the evidence. The opinion of appellee’s expert was based on such a lack of experience and knowledge regarding electrical lawn mowers, and the contrary evidence was so substantially supported by actual consumer studies that a verdict based on the former should be set aside and a new trial awarded so that justice may be given another opportunity to prevail. For the manufacturer to have ignored the results of its own market studies and, nevertheless, to have marketed machines making general use of deadman’s switches on non-riding, electrical lawn mowers would have demonstrated such a gross and willful disregard for the safety of members of the consuming public that it may well have supported a future award of *473punitive damages in favor of one injured as a consequence thereof. See: Martin v. Johns-Manville Corporation, Pa.Super., 322 Pa.Superior Ct. 348, 469 A.2d 655 (1983).
My review of the record suggests also that the weight of the evidence was clearly to the effect (1) that the legal cause of plaintiff’s injury was not a defective design of the electric lawn mower but the careless, if not reckless, act by which he inserted his hand into the blade to remove grass without turning off the lawn mower or otherwise disconnecting the supply of electricity; and (2) that the absence of a deadman’s switch on the lawn mower used by appellee was patently obvious to any user and that one who chose to use such a machine knowingly and voluntarily assumed the risk inherent in operating a power mower without a dead-man’s switch.
Finally, I am unable to agree with the majority that General Electric Company, which supplied an electric motor according to design specifications of the manufacturer and/or retailer of this electric lawn mower can properly be called upon to indemnify the manufacturer and/or retailer when either is found liable to a consumer for marketing a defectively designed machine. Because a thorough analysis of this issue is not essential to my view of the case, however, I leave further discussion of the right to indemnification in design defect cases until another day.
. All counsel, including counsel for Burch, concede that Burch did not turn off the machine before attempting to remove impacted grass. An apparently inconsistent statement in the record by Burch that he had “turned off” the lawn mower is attributed by his attorney to an error in transcribing the notes of testimony. Brief for Appellee, Paul Burch at p. 6. The correct transcription, counsel agree, would have been that Burch “turned over” the machine, not that he "turned off” the same.
. Reargument before a court en banc has been granted.
. See: Hollinger v. Wagner Mining Equipment Company, 667 F.2d 402, 410 n. 11 (3rd Cir.1981).
. It has sometimes been said that a witness may testify as an expert if he has any "pretension” to specialized knowledge. In my judgment, such a statement of the rule is unfortunate. I agree with Judge Spaeth that it is not "helpful to ask whether a witness has ‘any reasonable pretension to specialized knowledge,’ A ‘pretension’ is ‘an assertion or declaration whose truth is questioned or falsity suspected; an allegation of doubtful value; a pretext.’ Webster's New International Dictionary 1959 (2d ed. 1938).” Ragan v. Steen, 229 Pa.Super. 515, 528, 331 A.2d 724, 736 (1974) (Concurring Opinion by Spaeth, J.).