Probable Cause #11: Right Pilot, Wrong Equipment

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Even experienced pilots can have trouble if their plane has instruments they're not used to using -- or doesn't even have the right instruments for a particular IFR approach.

This article originally appeared in IFR Refresher, February 2005.

Probable Cause

In the past we have studied accidents that were the result of the pilot's lack of weather flying experience. In some of those reports we discovered that the lack of overall flying experience also contributed to the outcome.

This month we are going to look at an accident in which the pilot reported 14,300 hours of total flying time. Much of this time was in military transport aircraft, but he was also an ATP-rated civilian pilot and an instrument flight instructor.

The pilot worked part-time as a back-up pilot for a Nevada charter company that flew freight. According to the accident report he had worked in that capacity with the same operator from June 1990 until the accident in July 2002.

At approximately 12:45 p.m. on the day of the accident, the pilot landed at the Kneeland Airport (KO19) at Eureka, Calif., after a 170-mile flight from the Sacramento area. The pilot was en route to Arcata (KACV), Calif., which is located 17 miles northwest of the Kneeland Airport on California's northwest coastline.

According to California Department of Forestry (CDF) personnel, the pilot parked his airplane, a Piper Cherokee 140, on the side of the runway and ate lunch in their facility. They told investigators that it was common for pilots to land at KO19 when the weather at Arcata was poor. CDF personnel said that the pilot told them that he was on his way to Arcata to pick up an airplane for a charter flight that evening, adding that he did not appear to be in a hurry to get to Arcata. He also told them that the Cherokee he was flying, which he apparently owned with another individual, did not have all the instruments he was accustomed to flying with.

The pilot called a fellow company pilot at approximately 1:30 p.m. to ask what the weather conditions were at Arcata and was told that the skies were overcast at approximately 1,100 feet.

This was confirmed by the surface observation taken 23 minutes later, which indicated that the winds were from 280 degrees at five knots, the visibility was 10 miles, the ceiling was 1,100 feet overcast, and the temperature/dewpoint spread was three degrees Celsius.

The forecast for Arcata issued shortly before the two pilots had their conversation called for the winds to be from 270 degrees at five knots with a visibility of six miles or greater and an overcast ceiling at 900 feet. Temporary conditions between 5 p.m. and 6 p.m. called for scattered clouds at 1,500 feet but then conditions were going to deteriorate again, with an 800-foot overcast at 8 p.m.

For most experienced instrument pilots an 1,100 foot overcast ceiling would not be considered a tough approach, but keep in mind the statement the pilot made about his aircraft not having the instruments that he was accustomed to flying with.

At 2:15 p.m. the CDF personnel were called to respond to a fire. When they left O19, the pilot was still there. At that time, the weather in the Arcata area was said to consist of "patchy fog and breaking up."

A Sign Of Trouble?

Fifteen minutes later, the pilot, now airborne, contacted the Seattle Air Route Traffic Control Center and told the controller that he was three miles southeast of the KNEES intersection, which is located 15.8 miles southeast of the Arcata Airport along the ILS approach to Runway 32. He said he was in VFR conditions at 5,500 feet and requested the ILS approach into Arcata.

Although the controller issued a transponder code, he was never able to pick up the aircraft on radar. After verbally determining the pilot was outbound from KNEES, the controller then told the pilot, "Roger. Expect your approach clearance when you report inbound. Still no transponder. Try resetting again. We can do it non-radar. I would rather have the radar there." Two minutes later the pilot reported that he was a mile southeast of KNEES at 5,200 feet and inbound on the approach.

The controller cleared the pilot for the ILS approach to Arcata and told him to report his cancellation on the frequency in the air or upon landing. The pilot acknowledged the transmission.

Nearly two minutes later the pilot called back to say that he was breaking off the approach and going back to KNEES for a holding pattern, and then try again.

The controller acknowledged the cancellation and told the pilot to remain VFR. He said he still did not see the Cherokee on radar. He told the pilot that there would be another aircraft flying the approach and asked him if he would be staying in the localizer area. The pilot said that he would, and that he would stay at 5,500 feet to allow the other aircraft to go below him.

Several minutes later the Cherokee pilot called the controller and said, "I'm on the localizer now at 6,000 feet, VFR, requesting the approach in sequence." The controller acknowledged the request and told the pilot to remain VFR. He told the pilot to hold southeast of KNEES at 6,000 with left turns and that he'd issue him an approach clearance as soon as "I get some space," adding that there would about an eight-minute delay.

Five minutes later the controller called the pilot back and told him to report established inbound on the localizer course, and that he could expect an approach clearance at that time. The pilot asked if he could descend to 5,200 feet, which the controller approved.

When the pilot reported inbound the controller cleared him for the ILS approach. The controller provided the altimeter setting and told the pilot that the last aircraft that flew the approach broke out of the clouds at just under 1,100 feet. The controller then cleared the aircraft from the frequency and told him that he could talk to the controller on the ground as well as in the air on the same frequency. The pilot acknowledged the transmission and was not heard from again.

Too Low

Arcata (KACV) ILS Rwy 32 Approach Chart (click here for larger view)

When the airplane didn't arrive at KACV, a search was initiated and the wreckage was found almost 29 hours later, about 11 miles southeast of the airport. The airplane had impacted trees and came to rest inverted on the side of a heavily wooded, 45-degree sloped ridge at an elevation of 1,850 feet MSL. A post-impact fire had destroyed the entire cockpit and cabin area, including the ELT, which hampered the search effort. The pilot was fatally injured.

The 69-year-old pilot appeared to be qualified for the flight. Though his logbooks were never located, he had the licenses and required ratings. However, we do not know the level of his instrument currency.

The accident occurred about four miles inside the KNEES intersection, where the terrain is high when compared to the 218-foot elevation of the airport. The aircraft should have been at 5,200 feet before intercepting the glide slope just outside KNEES, which was located 15.8 miles from the localizer, I-ACV. Flying the glide slope, the aircraft should have crossed the ACATA outer marker, located 5.7 miles from the localizer, at 1,753 feet.

At the time the accident occurred, a localizer-only approach was not authorized, so a working glide slope was required to legally shoot the approach. Since then, a localizer-only approach has been added at KACV. It includes a step-down fix 10 miles from I-ACV, near the accident site, that requires pilots to cross no lower than 3,200 feet. Also, the MSA southeast of KACV is 6,500 feet.

The reason for the high altitudes is that the ILS approach to KACV is built right over the top of a ridge that runs along the approach course. There is a 2,386-foot peak between KNEES and the impact point, with a valley and then higher terrain to the right of the approach course.

At 2:53 p.m., approximately seven minutes before the accident occurred, the ASOS system at Arcata reported that the wind was from 280 degrees at five knots, visibility 10 miles, and the ceiling was overcast at 1,300 feet with a temperature/dew point spread of nine degrees. At 3:18 p.m., the ceiling was overcast at 1,500 feet, so the weather was improving.

A ceiling of 1,300 feet at Arcata would have meant the terrain southeast of the airport was obscured. It would appear that the clouds in the vicinity of the accident location could have been at the surface.

Know The Airplane

So we ask ourselves why a highly experienced pilot descended below safe altitudes when he had no hope of seeing the surface until he was almost over the airport? We'll never know the answer to that question, but we can speculate a little as to the pilot's actions and motives.

We don't know how often the pilot had flown into Arcata in the past, but since the entire area except for the coast itself is mountainous we have to assume that he was familiar with the fact that there was high terrain along the route of flight. He was aware of the 5,200-foot restriction on the ILS approach because he asked the controller if he could maintain 5,200 feet while he waited for the approach clearance.

Why then did the pilot, after he was cleared for the ILS the first time, reject the approach and hold in VFR conditions before accepting the approach clearance the second time? Is it possible that the glide slope in his airplane was not working? Did the airplane have a glide slope?

We don't know what equipment was installed in the aircraft because the NTSB report does not address it, although the pilot's partner in the aircraft told investigators that the aircraft was equipped for IFR flight. The entire instrument panel was destroyed by the crash and ensuing fire.

If the airplane's glide slope was inoperative, or if there was none installed in the airplane, then the pilot could not legally fly the ILS approach. The airplane ahead of the Cherokee reported no problems with the glide slope so we can assume that it was working properly.

The pilot's partner also told investigators that the pilot never flew without a hand-held GPS. At the time of the accident there was no GPS approach to Runway 32. But is it possible the pilot was trying to use a handheld GPS to fly the approach?

It would appear that he was trying to descend to cross the ACATA marker beacon at 1,753 feet. Since there was no localizer approach authorized, there were no minimum crossing altitudes published for an airplane that was not on the glide slope. If that is what he was trying to do, then he probably was not aware of the exact terrain layout below him.

What if he did not have an approach plate with him? While this is probably not the case, had it been he might have been trying to remember elements of the approach and did not remember the descent altitudes, or perhaps, that the approach could not be flown without a glide slope.

Did he make the mistake of thinking that he would break out of the clouds 1,300 feet above the surface, not realizing that the terrain remained high until he passed the 7.5-mile fix from I-ACV?

Whatever the Cherokee pilot was thinking and no matter what he intended to do, the pilot and his airplane were not clear of the high terrain. The pilot's positional awareness was not what it should have been.

What if he did have an operating glide slope in the aircraft? Why did he disregard the indication that he was below the glide slope and not climb back toward it? We know he was not used to flying the Cherokee on instruments, so it is possible that he blasted through the glide slope, although you would like to think that a pilot with as much experience as he had would be more proficient than that.

The Lessons Learned

So, the lessons to be learned are many. First, experience alone does not guarantee a good outcome. Experience coupled with currency and proficiency usually will allow a pilot more "maneuvering room" when something out of the ordinary occurs. But if the pilot disregards restricting altitudes that are placed on approach plates for safety, then the chances of an accident or incident occurring increase considerably.

While we don't know what equipment was installed in the airplane and the state of its maintenance, the controller never did pick up a transponder from the Cherokee, which would suggest that not everything was up to par. If the pilot deliberately began the approach with a piece of gear that was required but not present or not operating correctly, then he was asking for trouble. It is never a good idea to substitute a hand-held GPS for a required piece of gear. While GPS units are normally reliable, it is possible to have a less-than-sufficient signal on a unit that does not have an outside antenna installed, especially when the surrounding terrain is higher than the airplane.

It is vital that a pilot be thoroughly familiar with the airplane he is flying. Perhaps this pilot, though he owned a share of the airplane, was not. From his statement to the people at Kneeland, a logical assumption is that he rarely, if ever, flew the aircraft on instruments. Whether you are moving down or up, it is never a good idea to fly an airplane in instrument conditions in which you're not up to speed.

The last point is that the pilot was trying to get a job done. He was trying to get to Arcata to pick up an airplane and complete a flight for his employer. Did that fact interfere with his thought processes regarding the flight into Arcata? Should he have stayed at Kneeland longer? The weather was breaking and probably would have been better later.


More accident analyses are available in AVweb's Probable Cause Index. And for monthly articles about IFR flying including accident reports like this one, subscribe to AVweb's sister publication, IFR Refresher.