Understanding Night VFR and the CFIT Risk

On October 30, 1997, a Piper PA-34-200T Seneca departed Fort McMurray, Alberta, on a 62-NM charter flight to La Loche, Saskatchewan, with one pilot and five passengers on board. The aircraft departed at 17:50, and was expected back in Fort McMurray at 19:30. The pilot filed a visual flight rules (VFR) flight plan, and when the aircraft did not return, the Fort McMurray flight service station (FSS) operator initiated a radio search that was not successful. After the FSS contacted the operator, an airborne search party organized by the operator departed from Fort McMurray, but could not find the aircraft. Another search was organized using military resources and the wreckage was located on the afternoon of the following day. Three surviving passengers were taken by military aircraft to La Loche and then to Fort McMurray, with serious injuries. The aircraft was destroyed by impact forces and a post-crash fire. This summary is based on Transportation Safety Board (TSB) Final Report A97C0215.

The report states that the passengers were anxious to complete the trip in order to facilitate an appointment the following day. The pilot called the FSS to check the weather at Fort McMurray and Buffalo Narrows, and filed a visual flight rules (VFR) flight plan. The pilot consulted another company pilot who had returned from a flight to La Loche at 15:00, and was advised that the cloud ceiling was about 500 ft. above ground level (AGL) at La Loche and as low as 200 ft. AGL in some areas along the west shore of La Loche lake. On his last contact with the Fort McMurray FSS after departure, the pilot advised that he had departed the control zone to the east. A passenger reported that the aircraft was flying below the cloud at a low altitude shortly before the crash.

The wreckage was found at an elevation of about 1540 ft., and had struck the tops of poplar trees at an elevation of about 1600 ft. in a shallow descent, with a right bank angle of 10 to 15 degrees. The aircraft was on course, with the landing gear and flaps retracted, when it struck the trees. The shallow angle of the aircraft’s impact with terrain, and the speed of the aircraft at impact are consistent with controlled flight into terrain (CFIT).

An examination of the wreckage indicated that both engines were developing power at the time of impact, and no evidence of a pre-crash malfunction was found. The emergency locator transmitter (ELT) was destroyed in the crash and did not activate. The pilot was one of the more experienced company pilots. He had reportedly completed a pilot decision making (PDM) course, and was described as proficient and safety-conscious.

The weather at Fort McMurray at 18:00 included a ragged overcast cloud ceiling at 1000 ft. AGL. The terminal area forecast for Fort McMurray from 16:00 to 22:00 was as follows: winds 120 degrees at 8 kt., visibility greater than 6 SM, and an overcast ceiling at 1000 ft. AGL, with a temporary fluctuation of the visibility down to 4 SM and a temporary fluctuation of the ceiling down to 500 ft. AGL. The area forecast included the possibility of light to moderate icing in cloud.

La Loche is not served by an official weather reporting agency. However, pilots reported that at the time of the accident, La Loche was experiencing overcast cloud ceilings of about 500 ft. AGL and that ceilings were lower over the higher ground west of La Loche, in the direction of Fort McMurray. Although the pilot was qualified to complete the flight under instrument flight rules (IFR), the aircraft was not equipped for IFR flight under the prevailing conditions.

At the time of departure, the cloud ceiling met the requirements for night VFR flight in the Fort McMurray area. As the flight progressed toward La Loche, the cloud ceiling decreased below the minimum required for commercial air operations. Flight below the cloud left the pilot with reduced terrain clearance and increased the requirement for effective manoeuvring to avoid collision with terrain.

The lighting conditions on departure were likely sufficient to allow the pilot to maintain a visual reference to the ground. As the flight progressed, however, the available lighting and ground reference progressively decreased. The overcast sky, the decreasing sky illumination, and the dark colour of the forested area along the route and in the area of the accident yielded little light with which the pilot could manoeuver and navigate with reference to the ground.

The aircraft was not equipped with propeller or airframe de-ice or anti-ice devices. Such devices are required by regulation for an aircraft operating in known icing conditions. Section 602.115 of the Canadian Aviation Regulations (CARs) provides that night VFR flight requires a visibility of three miles; no minimum altitude is specified. However, section 703.27 of the CARs stipulates that an operator of an air transport service flying at night must maintain an obstacle clearance height of 1000 ft. AGL. Commercial night VFR flight must be conducted on a route, and air operators are required to maintain a record of company routes. The accident aircraft was reportedly not equipped with a route manual, nor was a route manual found at the operator’s base after the accident. Other pilots employed by the operator were not familiar with the obstacle clearance requirement found in the CARs, nor with the requirements of a route for night VFR flight.

Although the operator’s Flight Operations Manual (FOM) has detailed information on day VFR flight standards, the section on night VFR contains little guidance. The requirement for the minimum obstacle clearance height is not contained in the company operations exam, and the level of pilot awareness of the requirement within the company indicates that the pilots were not receiving the information from other sources.

Although it was not established whether the pilot was subject to pressures from the passengers, customer and self-induced pressures were encountered frequently by company pilots in their dealings with other customers. As well, the occurrence aircraft was already loaded with the passengers’ baggage prior to the pilot’s return from his previous flight, and a company pilot had recently successfully completed a flight from La Loche. It is not known to what extent the pilot’s decision to depart was influenced by one or more of these factors.

Among its findings, the TSB determined that the weather at departure from Fort McMurray was within allowable limits for night VFR flight; however, as the flight progressed toward La Loche, the cloud ceiling decreased below allowable limits for a commercial air operator, and the available lighting and ground reference available en route and at the time of the accident decreased markedly from that prevailing on departure.

The TSB also determined that the operator’s FOM contained little guidance to pilots on the subject of night VFR operations, and that company pilots were subject to customer and self-induced pressures from time to time to complete flights in adverse conditions.

The TSB concluded that the pilot continued flight into adverse weather and lighting conditions that did not enable him to avoid collision with terrain. Contributing factors to this occurrence were the aircraft’s unserviceability for single pilot IFR flight and the lack of guidance to company pilots as to weather limits for night VFR flight.

As a result of this accident, the TSB sent two aviation safety advisories to Transport Canada (TC) on night VFR requirements and night VFR routes in uncontrolled airspace, suggesting that (1) TC may wish to consider disseminating applicable information to operators; and (2) TC ensure this information is included in company operations manuals.

In addition to publishing this article, TC has also issued a Commercial and Business Aviation Advisory Circular to bring attention to the situation and ensure that company operations manuals contain all required information.

Don't Try This at Home

Artist's impression of impact.

The following occurrence exposes traditional and, unfortunately, often-repeated pilot errors: non-compliance, poor judgment and decision making, lack of crew resource management (CRM) and communication, and poor pilot technique. This synopsis is based on Transportation Safety Board of Canada (TSB) Final Report A97A0078.

Damage to the right-wing leading edge.

On April 15, 1997, a de Havilland DHC-6-300 Twin Otter departed St. Anthony, Newfoundland, on a visual flight rules (VFR) flight to Mary’s Harbour with 2 pilots and 12 passengers on board. The aircraft was flown under an overcast cloud layer along the Labrador coast when, about 10 mi. from Mary’s Harbour, the cloud base lowered and the crew realized that they would not be able to maintain VFR. They climbed to 2000 ft. above sea level (ASL), and then proceeded direct to the YMH nondirectional beacon (NDB) in instrument meteorological conditions (IMC). After crossing the YMH NDB, the captain flew a racetrack pattern for the NDB A circling approach, a company approach not published in the Canada Air Pilot.

The crew stated that one to two miles short of the NDB, the aircraft broke out of cloud at minimums and they could see the airport. They turned right, flew downwind, and entered a descending left turn to land on Runway 11. Just short of the threshold, at about 50 ft. above the ground, the captain realized that he could not position the aircraft for a safe landing, so he initiated a missed approach. He applied full power, selected flaps up to 10°, and levelled the wings. The aircraft crossed the threshold of Runway 11 on a heading of about 130°M and, unbeknownst to the crew, the right wing struck a tree off the right side of the runway. The captain continued eastward, joined the circuit for Runway 29, and landed safely. The crew discovered the damage to the aircraft while taxiing to the ramp. None of the crew and passengers was injured.

The captain and first officer had flown together previously but neither had received CRM training; the captain had received pilot decision-making (PDM) training five years prior to the occurrence, and the first officer did so three years prior to the occurrence.

St. Anthony is a sub-base for the company, and flight crews based there have no direct supervision and operate on a pilot self-dispatch system. Other than the annual mandatory check rides, the company does not perform periodic audits of the pilots’ operating standards or route checks, nor is it required to do so. The tree was about 20 ft. tall, located about 95 ft. to the right of the right edge of Runway 11 and 1200 ft. from the threshold. The tree was broken off 8 ft. 6 in. AGL, and it appears as though the wing struck it at that point. With the aircraft parked on level ground, the wing tip is about 11 ft. 6 in. above the ground. Damage consisted of an 18-in. tear running aft from the leading edge of the wing, 46 in. inboard from the wing tip, with damage to the internal wing structure and the de-icer boot.

Mary’s Harbour airport is uncontrolled and in uncontrolled airspace. The YMH NDB is a private NDB, and the only Transport Canada approved approach to the airport was the operator’s NDB A approach. There is a note on the approach chart stating that circling is not authorized north of Runway 11-29." Most of the airports along the Labrador coast are equipped for NDB approaches only and, generally, the instrument approach minimums at these airports are higher than VFR minimums. Therefore, flight crews will try to maintain VFR while flying between these airports in order to increase their chances of landing and completing their scheduled flights. The captain checked the en-route and destination weather before departing St. Anthony and determined that they would be able to get to Mary’s Harbour VFR. A VFR flight plan was filed but, because of marginal weather conditions in St. Anthony, a special VFR clearance for departure was required.

Standard operating procedures (SOP) had been developed by the company prior to the occurrence, but they had not been implemented into the company operations. SOPs ensure procedural uniformity and facilitate communication between crew members on issues such as changes to aircraft configuration and performance. Neither the captain nor the first officer communicated any altitude or descent information during the circuit procedure. Also, no communication took place regarding power settings, flap position, and proximity to the ground after the captain called for the overshoot.

Successful landings are normally preceded by a stabilized approach, where an aircraft has a constant rate of descent along the selected approach path; an appropriate, stable airspeed; a stable power setting; and is configured for landing. Both the captain and first officer stated that during the initial part of the overshoot the aircraft was flown at its best single-engine climb speed of 82 kt. with both engines set at maximum available power, propellers full fine, and the flaps at 10°.

The Flight Operations Manual cautions pilots that "In a go-around with flaps extended, the nose of the aircraft will point below the actual flight path." The stall speed with the wings level, flaps 10°, and an aircraft weight of about 12,000 lb. was calculated to be about 65 kt. Some of the passengers commented that they heard an alarm or warning horn during the latter stages of the approach and during the overshoot. The only sound that is similar to the passengers’ descriptions is the stall warning horn, which activates when the aircraft is approaching an aerodynamic stall.

Performance charts indicate that, with the flaps set at 10° and at an indicated airspeed of 78 kt., the aircraft should have been able to climb at about 1500 fpm at a climb gradient of about 0.18. The climb calculations assume take-off power, propeller rpm 96%, intake deflectors retracted, and no wind.

The report states that when he could no longer fly safely below the cloud, the captain elected to enter cloud, without filing an instrument flight rules (IFR) flight plan, and continue to Mary’s Harbour. When the aircraft broke out of the cloud prior to reaching the YMH NDB on the approach, the captain was faced with options. One option was to discontinue the instrument approach and join the circuit for a normal VFR landing. The other option was to complete the approach and land in accordance with the company NDB A, in which case circling north of the runway was not authorized. The captain’s course of action was not in accordance with either of these approved procedures.

When the crew saw the airport, there was adequate space to turn onto downwind and complete the circuit, but the captain did not adequately consider and compensate for the wind (027°M), which drifted the aircraft toward the runway during and after the turn onto downwind. During the turn onto base leg, the tail-wind component increased, which increased the aircraft’s ground speed. The result was that the aircraft was never established on a stabilized approach to the runway nor was it aligned with the runway down to as low as 50 ft. AGL.

The decision to overshoot was made when the aircraft was over the threshold of the runway, about 20° off the runway heading and at an altitude of about 50 ft. AGL. This decision was made too late and the procedure used was not aggressive enough to ensure obstacle clearance. A slow application of power, a settling of the aircraft when the flaps were raised, possible wind gusts, poor visual cues and pilot technique are possible reasons the aircraft did not climb immediately when the missed approach was commenced.

The TSB determined that the captain, in view of the wind and weather, did not adequately plan the last portion of the flight, and, as a result, he was not able to position the aircraft for a safe landing. He then delayed initiating the missed approach until it was nearly impossible to recover safely, although there must have been early indications that the final turn was not going to be successful. Then, given that the aircraft was very close to the ground when the captain initiated the missed approach, he did not fly aggressively enough to ensure that all obstacles in the flight path would be cleared.

In reviewing this article, the training folks here at Transport Canada commented that the development of an integrated program of commercial pilot training has identified a need to develop more pilot skills in handling circuits at lower, but still safe, levels. This type of training will be useful in getting pilots to be more proficient in handling IFR-to-VFR transitions, circling manoeuvers and other low-level VFR manoeuvering near the aerodrome.

To The Letter

Directional Control on Runway

Dear Editor:

After reading Transportation Safety Board of Canada Final Report A97Q0015, referenced in your "CRM Classic - Takeoff Gone Awry" article published in ASL 4/98, I was struck by the brief mention of, but not the emphasis on, what I believe may have really triggered the accident.

It is true from the crew resource management (CRM) aspect that a bad chain of events was set up by the crew. The trigger, however, was the directional control on the runway. I would bet that the pilot flying did not have enough, or, more likely, any aileron deflection into wind. I came to this conclusion before going back and checking the runway alignment and wind direction and, sure enough, there it was, a 50 degree crosswind at 20 kt. gusting to 30 kt.

Over the years, while supervising pilots, I have been astonished at the total lack of attention to deflecting ailerons while taking off and landing. It seems to be the very first thing that pilots forget after their private licence, yet it is critical input if proper directional control is to be maintained. On wet, icy, muddy surfaces with a crosswind, aircraft will drift downwind on the roll, both taking off and landing. The application of ailerons counteracts this. In extreme cases, full aileron is insufficient, but this generally coincides with exceeding the maximum crosswind tolerance of the aircraft.

Even on the most icy surface, proper application of ailerons enables good direction control in a crosswind, coupled with proper technique. Most aircraft that are not high-lift types are more forgiving under these circumstances. If you perceive that most newer pilots are flying nosewheel, non-high-lift aircraft and encountering crosswinds and slippery runway surfaces on an infrequent basis, then it is apparent that their level of competency is not too high. Associated with wrong technique, they are a set-up for disaster.

An argument may be made for differential power to correct drift, but this is application of a yawing technique that produces some weathercocking. The power settings are altered, and, assuming full power is set and required, the pilot is decreasing power on the upwind engine at a critical time, and increasing his ground roll. The proper application of ailerons will normally negate the need to adjust the power.

The report mentions only "...It appears that the loss of directional control was caused by the condition of the runway, the environmental conditions, and the late application of corrective measures." It does not mention what kind of control input the PF (pilot flying) was making (or not making). I don't like second-guessing without the facts, but if I am correct, if he is typical of what I have observed, then I am wondering if he has figured it out yet, ready for next time. To all pilots who drift unaccountably on runways in crosswinds, check the position of your ailerons!

Sincerely,
John Warner
Leduc, Alberta

Dear Editor:

In ASL 4/98, "CRM Classic - Takeoff Gone Awry," there is much talk of the first officer (F/O) giving an insufficient take-off briefing, not informing the pilot-in-command (PIC) of his difficulties maintaining directional control, and making the non-standard call "I have reached the speed." With phrases like, "It is possible that the PIC would not have cut power if the F/O had clearly and precisely communicated the loss of directional control of the aircraft and his intention to continue the takeoff," and "...the PIC had very little time to analyze the situation...," the reader is left with the impression that the poor PIC is simply a victim of a bad situation.

Based on your account, the PIC was the major cause of this accident. The first thing I learned in my two-crew training is that, at the command of the PF (pilot flying), in this case the F/O, the PNF (pilot not flying), in this case the PIC, sets and maintains take-off power, monitors the engine instruments and airspeed, and makes any calls covered in the take-off briefing loudly and clearly enough for the PF to hear them. The PNF is not relieved of these duties until after climb power has been set. Had the PIC followed this most basic rule of crew resource management (CRM) there would have been no incident no matter what deficiencies there were on the part of the F/O. This incident happened only because the PIC did not call V1 loudly and clearly enough, and then made the cardinal sin of abandoning his duties altogether by looking out the window. It makes this reader wonder how much of the directional control problems were caused by an asymmetrical power setting by a PNF who was looking out the window instead of doing his job.

Sincerely,
Ian Shipmaker
Salmon Arm, B.C.