In this suit to recover damages for-personal injuries, the district court directed a verdict against the plaintiff and he has appealed. His assignments off error all concern the validity of that ruling.

Plaintiff based his claim on-negligence. His complaint was in two-counts. In one he charged that the defendants were responsible under the doctrine of respondeat superior for the negligent operation of a crane by their employee, Ed Choy; and in the other, he-charged under an exception to the fellow-servant rule that the defendants were-themselves negligent in employing Choy, whom he alleged was an incompetent operator. 1

“Although stated in varying-ways at different times, the question a. trial court must answer in deciding-whether to direct a verdict (for the defendant) is ‘whether the evidence in its-entirety would rationally support a verdict for the plaintiff, assuming that the jury took, as it would be entitled to-take, a view of the evidence most favorable to the plaintiff.’ ” Phipps v. N. V. Nederlandsche Amerikaansche Stoomvart, Maats, 259 F.2d 143, 145 (9th Cir. 1958), quoting Justice Frankfurter concurring in Wilkerson v. McCarthy, 336 U.S. 53, 65 , 69 S.Ct. 413 , 93 L.Ed. 497 (1958). And this court, in common with other appellate courts, applies the same *350 test when reviewing a district court order. Sherwood & Roberts-Kennewick, Inc. v. St. Paul Fire & Marine Insurance Co., 322 F.2d 70 (9th Cir. 1963).

In this case the evidence disclosed that Concrete Engineering Company (Concrete) had entered into a subcontract with the construction firm of Haas & Haynie to manufacture and erect the framework for a four-story parking garage in Honolulu. The structural components of the frame were to consist of prefabricated concrete beams, joists and soffits of a type manufactured by Concrete at its plant. 2 They were hoisted into place by means of cranes.

The plaintiff, Warren McCollum, was Concrete’s engineer in charge of construction. His duties included deciding how the work was to be done, inspecting the materials before they were installed, interpreting the blueprints and directing Concrete’s workmen on the job.

When the work of building the top story of the building commenced, Concrete had no crane of its own capable of reaching to that height; accordingly, plaintiff rented a large mobile P & H crane from the defendants, Orvil Smith and Chan C. Wilson who, as partners, carried on the business of leasing construction machinery. The rental agreement was oral and, so far as the evidence shows, was simply that for $70.00 per hour defendants would supply Concrete with the crane, an operator, and an oiler.

On Sunday, the power unit for the crane was driven to the job site. There, as specified by plaintiff, it was outfitted with a boom consisting of a main section 170 feet in length, together with a jib or second section 40 feet long that extended from the far end of the main section at an obtuse angle. The line ■or lines used to hoist loads ran down from the tip of this latter section.

On Monday, the crane, operated by defendant’s employee Edward Choy, was put to work. The building materials were heavy and bulky. Lifting them was a very delicate operation, not only because of their weight but also because of the great length of the boom and line. And unless the load was directly beneath the tip of the boom when the lift began, it would sway in a considerable arc when raised from the ground, creating a hazardous condition. Choy, being seated beside the base of the boom, was himself unable to gauge, with any degree of accuracy, the position of the boom tip with reference to the particular load. He was given this and other needed information by one of the loaders who, through the use of a series of pre-ar-ranged signals given by hand and arm, would indicate where to move the boom, the location and position of the line and when to make a lift.

Some of the beams were forty feet long and weighed as much as 6,000 pounds. For lifting, they were attached to a sling fashioned of two cables, each bearing a hook at one end and the other fastened to the boom line. These hooks were inserted by workmen into a stirrup-like loop built into either end of a beam. After the hooks were set, the usual practice was to first raise the beam slightly so that it hung free of the ground. If the alignment with reference to the boom tip appeared correct, a signal would be given Choy to proceed, but otherwise he would be directed to lower the beam and reposition the boom.

The accident occurred on Thursday. Plaintiff was standing on the semi-trailer of a truck that had only recently brought in a load of forty-foot beams. He was helping hook them up and acting as signalman. After Choy had made some preliminary boom adjustments, plaintiff testified that he gave Choy the hand and arm signal meaning simply “ready to test, go ahead”; that Choy immediately, and without first allowing the line to be cheeked or receiving any clearance, commenced to make the actual lift; that the beam thereupon swung like a pendulum, striking plaintiff with great force and *351 causing him to be violently knocked from the trailer to the ground.

From this evidence, taken at full value, it appears that Choy ignored or failed to correctly interpret plaintiff’s signal, and took none of the usual precautions before commencing a move that was potentially harmful to plaintiff. We have no hesitancy in holding that such evidence would support a finding that Choy was negligent.

However, as an affirmative defense, defendants denied responsibility for their employee’s acts on the ground that Choy, although in their general employ and operating their equipment when the accident happened, had ceased to be their servant and, for the time being was, with respect to the work being performed, the servant of Concrete— in short, that he was a loaned servant. If the evidence positively and unequivocally establishes that such was Choy’s status, then the defendants, of course, are not responsible for the consequences of his negligent acts, for the rule is “elementary” that:

Denton v. Yazoo & M. V. R. Co., 284 U.S. 305, 308 , 52 S.Ct. 141, 142 , 76 L.Ed. 310 (1932). But if it appears debatable that Choy was then the servant of Concrete, the question whether there was a change of masters was one of fact for the jury.

In deciding this issue, a factor usually considered to be controlling is the location of the power to control the servant, for responsibility is regarded as a correlative of power. The Standard Oil Co. v. Anderson, 212 U.S. 215 , 29 S.Ct. 252 , 53 L.Ed. 480 (1909); Chicago, Milwaukee & St. Paul Ry. Co. v. City of Tacoma, 7 F.2d 586 (9th Cir. 1925); Western Marine & Salvage Co. v. Ball, 59 App.D.C. 208 , 37 F.2d 1004 (1930); Nepstad v. Lambert, 235 Minn. 1 , 50 N.W.2d 614 (1951); 17 A.L.R.2d 1388 , 1393, § 2.

But as the above cases make clear, it is not essential, in order to constitute an employee a loaned servant, that thfe general employer relinquish full control over his employee, or that the special employee be completely subservient to the borrower. While the latter must possess the power of “authoritative direction and control” over the employee [Standard Oil v. Anderson, supra 212 U.S. at 222 , 29 S.Ct. at 252 ] so that his directions will have “the force of a command” [Denton v. Yazoo, supra, 284 U.S. at 310 , 52 S.Ct. at 142 ], this authority need not extend over every incident of an employer-employee relationship, but only over the servant’s performance of the particular work in which he is engaged at the 'time of his negligent act or omission. As the Minnesota Supreme Court declared in Nepstad v. Lambert, supra, a particularly illuminating opinion discussing this subject,

A careful consideration of the •entire record in the light of these propositions makes manifest the conclusion that Choy was the servant of Concrete, so far as the outcome of this case is con■cerned.

As previously noted in this opinion, ■defendant’s agreement with Concrete was to rent the crane complete with operating personnel. Their compensation in no way depended upon how much or how little the crane accomplished, but rather upon the number of hours it was ■operated. They did not undertake to perform any work. What was to be done with the crane and the time that would be required to do it were matters left for Concrete to decide. Concrete, rather than defendants, had and interpreted the plans for the building. Concrete scheduled the installation of the various building components, had them hauled to the job site from time to time as needed, and Concrete regularly directed Choy precisely where to set them. The work of the ■crane was such that Choy was eontinu■ally required to take orders from and 'closely follow the directions given by Concrete through plaintiff, who was in charge of the job. For example, during the progress of the work, plaintiff caused 'Choy to drive the mobile crane unit to ¡several locations adjoining the structure, in order to comport with plaintiff’s building schedule. He specified which particular beam or soffit should be hoisted at a given time, and not only directed Choy where to place it but required him to make nice adjustments in its position ■and hold it in place while it was being incorporated into the frame. In short, it nowhere appears that Concrete engaged defendants to perform a certain job, but rather that Concrete rented defendants’ machine and operator in order to do some work of their own and in their own fashion; the crucial right of control over those who performed this work unmistakably rested with Concrete.

Plaintiff’s second ground for recovery likewise lacks substantial evidentiary support. Specifically, there was no proof that at the time defendants employed Choy he was not competent to operate the crane in a reasonably safe manner or that thereafter he would be negligent; nor was there any evidence adduced which would tend in the slightest degree to then, or thereafter, forewarn defendants that Choy would probably be careless while in their employ.

Briefly, what does appear is that Choy was a crane operator by trade; that he had more than ten years’ experience in that vocation, gained from continuous employment with a number of internationally known construction companies, and that he was familiar with the very type of P & H mobile crane involved in this accident, having operated them on prior jobs. Plaintiff makes much of the fact that the first day on this job Choy allowed to slip and start to settle a soffit he had hoisted and was holding, awaiting further instructions, and that on the following day Choy swung a beam above the building almost striking a workman who was standing on an inner portion of the frame. Plaintiff mentioned both matters to one of Choy’s superiors. However, plaintiff’s own version of these incidents makes it clear that neither incident could be fairly attributed to Choy’s dereliction of duty.

In conclusion, we are fully satisfied that the trial judge correctly appraised the evidence and that his ruling was right.

The judgment is affirmed.

. The fellow servant doctrine, which exempts an employer from liability for injuries to a fellow employee by the negligence of a co-employee, is subject to an exception if an employer knows or is chargeable with notice of the fact that the tort feasor is likely to be careless in performing the service in which he is engaged. The employer being duty bound to provide his employees with safe instrumentalities and surroundings, his selection or retention of a notoriously careless employee constitutes actionable negligence on the part of the employer, should the co-worker negligently injure one of his fellow workmen.

. The soffits were the lower segments of the composite beams upon which the joists were rested.