RUAPEHU AIR DISASTER DUE TO AN ERROR OF PILOTAGE, SAYS OPERATIONS MANAGER OF N.A.C.

Gisborne Herald, Volume LXXV, Issue 22816, 10 December 1948, Page 6

RUAPEHU AIR DISASTER DUE TO AN ERROR OF PILOTAGE, SAYS OPERATIONS MANAGER OF N.A.C.

(PA.)

WELLINGTON, Dec. 10

The opinion that the disaster costing 13 lives when the N.A.C. aircraft Kaka crashed into a rock outcrop on Mount Ruapehu on October 23 was due to an error of pilotage on the part of the pilot was given by the corporation operations manager, Mr. Andrew Graham Gerrand, himself an experienced pilot, in evidence yesterday afternoon before the board of inquiry which has been seeking the cause of the accident.

Mr. Gerrand said that additional navigational aids in the vicinity of the mountain might have lessened the probability of such human error as he thought had occurred. He told the board that navigational aids now in use in New Zealand, and still being installed, were obsolescent and were being dispensed with in some countries.

He said that the installation of any full coverage aid would involve great expense and, as the world authorities were still arguing about the type of aids to instal, it was understandable that New Zealand was m-jking haste slowly. He agreed with earlier witnesses that an additional radio homer to the west of Ruapehu would help pilots.

“The operations manager at Palmerston North gave this man the clearance thinking he had fulfilled the practice of lodging the complete plan at Paraparaumu,” continued the witness. “Had he known that was not done he would have made the pilot fill in the complete flight plan at Palmerston North, but he did not know it because there was no ring from Paraparaumu and because the pilot did not ask for it.” The witness said that any pilot who did not have the usual flight plan with him should prepare one in the air. When the pilot signed the flight plan, which included a statement that he had studied the weather advice, that relieved the operations staff of some responsibility. Had Flown Over Route “I do not think that Commander Hare failed in that respect in any way on this occasion in that he had received the forecast at Whenuapai that morning and had flown over the route and was turning round to fly back over it,” continued the witness. “The usual weather briefing at a turn-round point, if any, consists of the pilot briefing the meteorologist, rather than vice-versa.” There was no supervision of a pilot's weather briefing. The witness considered it a good practice to leave the decision on flight cancellation to the pilots, who were usually the best judges of their own limitations and abilities. The chairman, Sir Harold Johnston: Do you believe a man is really the best judge of his own ability? The witness said he thought it was so in such occupations as that of a pilot.' which depended on correct judgments. The chairman: Is there not some more objective way? Problem Under Consideration The witness said that the problem had been under consideration for some time. He knew of an American school of thought whereby flight cancellations were determined jointly by the pilot and a plane despatches but he thought the British school of thought, which differed from the American, had more adherents. However, operations officers of specified seniority in the N.A.C. could cancel a flight, although they could not order a pilot to proceed. Replying to Wing Commander J. W. H. Bray, a member of the board, the witness said that the entries in the log found in the Kaka were obviously insufficient.

In continuing his evidence, after lunch, the witness, Philip Ernest_ Hudson, technical assistant in the Air De-

partment, said the wind in the area was said to be stronger than had been forecast. He computed the true airspeed at 150 or ICO m.p.h. He assumed that the Kaka passed over the Wanganui homer at 1.37 p.m. and that the crash occurred at 2.3 p.m. and that the aircraft had, as reported, passed close to Okoia. Using the forecast of 11 degrees of starboard drift, it would need a wind velocity of 70 to 75 knots from 305 degrees for the Kaka to crash where it did. If seven degrees of starboard drift had been allowed for (similar to the port allowance made on the southward trip) the wind would have had to be 66 to 68 knots from 305 degrees to bring the plane to where it crashed. Possible Allowances For Drift Assuming that no allowance for drift

were made a wind from 315 degrees of 50 knots, or from 320 degrees of 55 * knots, would have been required to take the aircraft to the point of the crash. All those hypothetic winds were considerably stronger than a wind of 40 knots from 320 degrees as mentioned in the report of Walter Ralph Dyer, the officer in charge of aviation forecasts at the Meteorological Office, who gave evidence earlier in the week. If an allowance were made for drift of seven degrees to port, that would have meant the course was set seven degrees to the right of the track required. Under those conditions a wind from approximately 330 degrees of 39 to 46 knots could have brought the machine to where it crashed at 2.3 p.m. It might have been possible for tfie pilot to estirriate the drift immediately after the aircraft began to climb from

4500 ft. after picking up the Wanganui homer, but such an estimate would not be a reliable, check. On the other hand, it might have been possible, after attaining 6000 ft. to check the drift by t radio-compass bearing on the Wanganui homer.

He added that while no headings were provided for columns in the log forms suplied to pilots, he did not think insistence on standardised headings for the' columns would induce pilots to enter fuller details. Specific headings were formerly provided, but it was found that pilots tended to scratch out those they disliked.

Twenty -Miles Off Course

The position of the crash was about 20 miles off the proper course and was about 22 degrees in angle off the course at the time of the accident. The witness. Hudson, added that setting the drift to port instead of to starboard was an error made at times by pilots, but it was not an error one would expect an experienced pilot used to mental navigation calculations. An experienced pilot would know that, with a track due north and a wind from the north-west, he could assume that his drift would be to starboard.

The witness thought that the keeping of a dead-reckoning log by pilots on this form of scheduled airline operations should be optional. Replying to Wing Commander Bray, who said the log as found in the wreckage left much to be desired, the witness said he personally thought it more likely to have been kept by the co-pilot than the commander. He favoured pilots being given freedom to follow that form of log entry which they individually found most convenient and quick.

The witness said that any explanation he might offer as to how the Kaka got to Ruapehu after leaving Wanganui would be purely conjectural and of no value

Another Homer Desirable

Mr. D- W. Virtue, appearing for the N.A.C.: The only way, as I understand your evidence, that you can explain the accident is in regard to the application of drift computations. That presupposes both the commander and the co-pilot falling into the same error?

The witness agreed with Wing Commander Bray that the flight-plan drift could easily be used in spite of operational instructions and so that drift could be very important. He also agreed that a homer in the area between Wanganui and Hamilton was desirable, although it was not a necessity. The chairman: What additional aids to navigation are desirable to lessen the possibility of future accidents? The witness, Gerrand: Other aids may have lessened the probability of such an accident, but I am satisfied that this accident was because of a pilotage error on the part of the pilot, which is a specific form of human error, carelessness—or call it what you will—and no mechanical aid will entirely eliminate those. I agree that mechanical aids would lessen the probability of them. The chairman asked what type of navigational aids the witness would suggest. Had other countries anything which New Zealand did not have? The witness: Yes, they have various types of V.H.F. ranges and beacons—there are hosts of navigational aids. World experts, added the witness ness were still arguing which were best. All of them had some drawback or another. As the world experts could not agree, he, the witness, would be foolish to jump in. The chairman: Are we to stand still? Are we really behind them? The witness: The aids that are here and the ones we are going on with are obsolescent, and in some countries are being dispensed with. The chairman: Haven’t we got a real remedy?

The witness: I am not sure to what extent the co-pilot checks the commander’s navigation. If the co-pilot sat in the control cabin and saw the commander steering a course on the wrong side of the track, he would pick it up pretty quickly?—Yes, 1 agree: but it was apparent the co-pilot was not making navigation calculations. He was recording certain calculations, although his computer does show he made computations on the way south. Sharing of Duties

Replying further to Mr. Virtue, the witness, Hudson, said it was possible the co-pilot had ' continued similar work on the way north, but that touched on the question of sharing of duties -between the commander and co-pilot, of which the witness could not speak. He agreed that it was surprising that both men should be under the same error, if that error was madeThe change in wind as between that encountered on the way south and that forecast for the journey north was from 330 degrees and 40 knots to 310 degrees and 30 knots, but the change in direction virtually offset the decline in strength and should not have caused any error. The witness said he had considered the possibility that the aircraft’s magnetic content might have been affected by lightning, but he could recall, over a period of years, only two or three authenticated cases of that occurring. Had it happened to the Kaka he thought Commander Hare would have taken appropriate action, turning to the westward with the idea of descending to a level that would enable him to complete the flight by visual-flight rules.

Making Haste Slowly

The witness said the Air Department and the N.A.C. had been considering the question over some years. The installation of any full-coverage aid would involve an expense of very very large sums of money and while the state of indecision existed elsewhere, it was understandable that New Zealand was “making haste slowly.’’ The increase in navigational aids in New Zealand in the last 12 to 18 months had been considerable. Three mediumfrequency radio ranges and 12 or 13 homing beacons had been installed. The position was definitely being improved all the time.

Stronger Than Forecast

Mr. Virtue: If it is unlikely an error was made, in applying the drift calculations. does that not suggest the Kaka probably encountered exceptionally strong winds—much stronger than those forecast? The witness: If one theory is rejected, the other must be true, but 1 think it unlikely that there were winds of 60 or 70 knots. That is for the meteorologists to say. Andrew Graham Gerrand, operations manager for the National Airways Corporation, said that Gerald Whincop, the stand-by pilot who had given evidence earlier, was approved by the corporation for the preparation of instrument-flight plans. _ He did not possess an instrument rating. Those flight plans were not for navigational purposes and Whincop was not competent to prepare such plans, but the plans for air traffic control were only for purposes of traffic control. The purpose of the inclusion of wind data was to enable the estimated elapsed time to be arrived at for air traffic control. There was no direction that they should be prepared by the pilot in command of the aircraft and it was the general practice for stand-by pilots to prepare them. The practice of entering drift on the flight plan had not been required of the stand-by pilot, nor was it required by the pilot in command, who would normally make those calculations independently. Failed to Ask for Flight Flan

The Air Department in the last two years had taken a much greater interest in that sort of thing. They were the responsibilities of the Air Department, which had a Radio Navigational Aids Committee to which the corporation was regularly invited. That committee put forward recommendations to the Controller of the Civil Aviation Branch for consideration and for forwarding, the witness supposed, to the Treasury. The inquiry was adjourned until today, when it is expected the evidence will conclude. In that event counsel will address the board on Monday.

As far as anyone could ascertain, Commander Hare failed to ask for a flight plan at Palmerston North, continued the witness. The operations procedure required the pilot to take a flight plan with him, but not necessarily the original of the air traffic centre flight plan. A flight plan was of use in an aircraft.

Social-Activities Day When executive members of the Gisborne Returned Services’ Association concluded their final meeting of the year on Wednesday, with an exchange of seasonable compliments, it was remarked that the gathering was not in fact the last occasion on which they would meet prior to the Christmas season. On Saturday several executive members will assist in conducting the annual R.S.A. bowling tournament, an all-day fixture, while others will support the social committee in conducting the children’s fancy-dress party in the Army Hall on Saturday afternoon. An additional function to which executive members have been invited is the windup of the R.S.A. Male-Voice Choir’s programme for the year, to be signalised by a gathering on Saturday evening following a visit by the choir to the Memorial Home.