August 1, 2004
By Bruce Landsberg
Bruce Landsberg, executive director of the AOPA Air Safety Foundation, makes a practice of flying well above the MEF at night.
Last month we discussed night-VFR cross-country accidents and invited you to the accident analysis section of the AOPA Air Safety Foundation Web site to look at the record for yourself. It's pretty sobering. I suggested that you could avoid drilling holes in hills at night or in marginal-VFR conditions by flight planning to avoid terrain using only a sectional or an IFR en route chart. In the see-and-avoid equation, if you can't see, it's imperative to have a plan to avoid. This month we'll look at the consequences of not verifying those small but very important details such as maximum elevation figures, or MEFs. A seemingly inconsequential item, such as prescription eyeglasses, also may have played a role in one accident.
Several years ago, in late January, a pressurized Piper Aerostar 601P crashed into mountainous terrain at 6:54 p.m. Pacific Standard Time. The flight departed Chico, California, at 6:37 p.m. en route to Ukiah, California. The weather was excellent except for the fact that it was dark. At Chico Municipal Airport, located 32 miles northeast of the accident site, the wind was reported from 340 degrees at 5 knots, visibility 100 statute miles, scattered clouds at 20,000 feet. Ukiah Municipal Airport, 30 miles to the southwest of the accident site, reported the wind from 260 degrees at 3 knots, visibility 10 statute miles, clear sky, temperature 5 degrees Celsius, dew point minus 2 degrees Celsius. The moon was nearly full but had not risen at the time of the accident.
Prior to the accident flight (from Chico to Ukiah), the pilot flew to Chico to pick up two passengers, flew to Oakland, and then returned them to Chico that afternoon. The pilot lost his near-vision glasses while they were in Oakland. The passenger had a pair of near-vision prescription glasses and lent them to the pilot for the remaining flight legs. The pilot kept the glasses after delivering the passengers to Chico and agreed to mail them back to the passenger after returning to Ukiah.
The pilot contacted the Oakland Air Route Traffic Control Center (ARTCC) just before 6:51 p.m. and advised, "I'm about halfway between Chico and Ukiah, en route Ukiah at 6,700 descending, squawking VFR. I'd appreciate flight following and vectors to Ukiah." The controller radar-identified the airplane, confirmed the altitude, and requested the current heading. The pilot indicated the airplane was flying a 230-degree heading. At 6:52, the controller advised the pilot to fly a heading of 220 degrees to reach Ukiah, which the pilot acknowledged.
The controller then transferred position responsibility to another controller after briefing him on the traffic situation. At 6:53, the pilot requested distance information to Ukiah and was advised that Ukiah was 34 miles away. About 15 seconds later, the pilot asked if the radar groundspeed showed 181 to 185 knots. The controller gave the aircraft speed readout as 182 knots. That was the last communication, and the final radar return was received one minute after that, at 6:54.
At 6:56, the controller advised that radar contact was lost, and he probably would not receive radar information until the aircraft was about five to 10 miles from Ukiah "due to limited radar coverage in that area." The pilot did not respond to that transmission, and the controller made several radio calls attempting to contact the pilot. After multiple attempts including other aircraft and ATC sectors, search-and-rescue procedures were initiated.
The wreckage was located near the peak of St. John Mountain. The accident site was located at the 6,700-foot level of the 6,746-foot mountain. The pilot, who was the sole occupant of the airplane, was killed. He held a private pilot certificate with single-engine, multiengine, and instrument ratings. His second class medical certificate was issued with a limitation that he "must wear corrective lenses and possess glasses for near and interim vision." According to an aviation insurance renewal application, the pilot had approximately 2,830 total flight hours, of which 750 were in multiengine airplanes. The last flight review had been accomplished about 18 months prior to the accident. The pilot logbooks were not located, so it is unknown how much night flight, instrument flight, or Aerostar time had been recorded.
There were no apparent problems with the aircraft that would have played a role in this accident, according to the NTSB. It is unknown whether the aircraft was equipped with a GPS, moving map, or other area navigation equipment.
After the accident, an air traffic control analysis group was formed to examine the details as they related to ATC. The following information is summarized from that report: The distance between Chico and Ukiah is approximately 70 miles with mountainous terrain varying from 3,000 feet to just above 7,000 feet between the two airports.
Radar contact is commonly lost with aircraft flying at 6,500 feet along similar routes to that of the Aerostar, but radio communication is normally maintained. The route is a common corridor between Chico and Ukiah and is routinely flown VFR at altitudes between 6,500 and 10,500 feet, day and night.
The sector radar video map did not depict symbology representing terrain or obstructions in the vicinity where the wreckage was located. Maps and sectional charts were located overhead and to the left of the controller's workstation.
The general ATC procedures allowed radar vectors in accordance with FAA Order 7110.65, paragraph 5-6-1. The chapter states in part: "Vector Aircraft: In Class G airspace only upon pilot request and as an additional service. NOTE — VFR aircraft not at an altitude assigned by ATC may be vectored at any altitude. It is the responsibility of the pilot to comply with the applicable parts of CFR Title 14."
The guidance on safety alerts is also outlined: "Immediately issue/initiate an alert to an aircraft if you are aware the aircraft is at an altitude which, in your judgment, places it in unsafe proximity to terrain/obstructions."
The controllers who handled the Aerostar are identified as Controller 1 and Controller 2 (the controller who relieved Controller 1). Both were experienced with more than 10 years each working at the Oakland ARTCC. Both described the traffic on the day of the accident as normal with no complexity, and indicated there were very good VFR weather conditions. The sector does a lot of flight following and approach service to two towered and about 20 to 25 nontowered general aviation airports. Controller 1 had been on position for about an hour when the accident pilot made initial contact and was relieved by Controller 2 as described earlier.
Controller 1 was not exactly sure where the pass was located, but reported the Aerostar did not appear unique. He had issued safety advisories in the past "when circumstances warranted." He normally would not provide an advisory of the minimum instrument flight rules altitude (MIA) to a VFR pilot, but might ask if "terrain is in sight." He said he would bring up the MIA map if he felt "uncomfortable" but everything seemed normal. He knew the area and that the pilot was entering a 9,100-foot MIA section but did not know what the controlling obstacle for that section was since it was not marked on the radar display.
Controller 2 noted the pilot requested distance information from Ukiah, and the controller responded, 34 miles. (This put the flight in the vicinity of the highest terrain.)
Controller 2 reported there was no way of knowing the specific height of the terrain in that area because it is not depicted on the video map. He added the only obstructions on the video map are Mount Shasta and Mount Lassen, both of which are far from the accident site.
Controller 2 knew it was dark while he was handling the Aerostar, but the weather was clear and he recalled being able to see Ukiah easily during a recent familiarization flight. When asked if he had ever issued safety alerts he said he had when he felt an aircraft was in close proximity to terrain or obstructions. He did not feel a safety alert was warranted in this case as nothing indicated that the pilot was in danger.
The Oakland ARTCC computer is equipped with an E-MSAW (en route minimum safe altitude warning) feature, which alerts the controller when a tracked aircraft is below, or predicted by the computer to go below, a predetermined altitude. E-MSAW is not automatically activated for VFR aircraft; however, controllers may enable the display of E-MSAW processing by a computer entry. Activation of E-MSAW is required only under emergency situations or by pilot request. Both controllers reported they had never had a pilot request E-MSAW information and did not know how to activate the system for VFR airplanes.
The San Francisco Sectional aeronautical chart shows that a straight-line ground track between Chico and Ukiah would have taken the flight just south of St. John Mountain and Snow Mountain. An area of lower terrain through the mountains was approximately five miles to the south of the flight track. The sectional depicts a maximum elevation figure (MEF) for the accident site quadrant as 7,400 feet. The MEF is based on information available concerning the highest known feature in each quadrangle, including terrain and obstructions such as trees, towers, and antennas. The MIA for the area is 9,100 feet. Either would have kept the flight above the terrain. (See www.asf.org for a mini course on terrain avoidance planning.)
The Aeronautical Information Manual (AIM) recommends the following during mountain flying: "Plan your route to avoid topography which would prevent a safe forced landing. The route should be over populated areas and well-known mountain passes." The AIM's Pilot/Controller Glossary has a listing for "flight following"; however, it then instructs one to "see traffic advisories." The traffic advisory section in the glossary does not refer to any altitude clearance information. Section 4-1-15 of the AIM covers the safety alert, which is "issued to pilots of aircraft being controlled by ATC if the controller is aware the aircraft is at an altitude which, in the controller's judgment, places the aircraft in unsafe proximity to terrain, obstructions or other aircraft. The provision of this service is contingent upon the capability of the controller to have an awareness of a situation involving unsafe proximity to terrain, obstructions and uncontrolled aircraft." The AIM also instructs pilots on the use and issuance of MSAW and reiterates that the service is automatic for IFR operations; however, VFR aircraft have to request MSAW.
There was no egregiously bad judgment here, in my opinion — just a basic fatal error. Night flight has one of the highest potentials for fatalities so there is no substitute for knowing where you are and where the terrain is. A few hypotheses, which may be completely off base, are offered. We'll rule out hypoxia because the aircraft was pressurized and the cabin would have been close to sea level — certainly not high enough to cause a deterioration of night vision. In an unpressurized aircraft, that might have been a factor.
The loss of the pilot's glasses might have affected his vision somewhat and while he borrowed some reading glasses to help with the close-up view, his long-distance vision may have been degraded. Fatigue also may have played a part as the pilot was well beyond middle age and was on the fourth leg in moderately busy airspace that day. Fatigue is a subtle incapacitator that has to be considered after a long day. We are not at the top of our game when we are tired, and the aging process just doesn't help matters.
Experience works both for and against us. It's good in that we know the danger areas and it's bad because we've dealt with them before and survived. ATC, as it has been said many times, is not there to keep VFR pilots out of the weeds even though they do it on occasion. Complacency is probably one of the biggest threats to otherwise careful pilots. This pilot was making the effort to coordinate with air traffic control, was generally familiar with the terrain since he lived in Northern California, and yet still fell victim to a very old aeronautical axiom: What cannot be seen must still be avoided.
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The silence on the approach control frequency is broken as the controller speaks your N number and advises, “Traffic, two o’clock, westbound, type and altitude unknown.”
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