You probably know when an alternate airport is required for an IFR flight. But if you pick an alternate that is affected by similar weather patterns as your destination, how useful will it really be? When the destination weather is in the toilet, you may have to motor down the airway some distance before you find a useful alternate.
This article appears in the November 2002 issue of IFR Refresher magazine, and is reprinted here by permission.
When you file an instrument flight plan to a destination, you are required to list an alternate airport if the weather at your original destination is forecast to be below 2,000 feet or below three miles visibility for an hour before and after your expected arrival time. While it is unusual for weather in a large area to suddenly deteriorate, you should opt for an alternate that is forecast to remain well above landing minimums for the period. In fact, you are required to locate an alternate that meets the 600 and two or 800 and two test, depending on the type of approaches that are available. The alternate requirement is a preflight exercise. You are not required to go to your chosen alternate if you don't get into your original destination. On the other hand, how smart is it to opt for an airport that has marginal weather after making a missed approach at another airport? Perhaps the accidents that you are going to read about will help you make your decision the next time that you're confronted with that situation.
Into The Weather
The pilot of a Cessna 402C departed Charlotte for Wilkesboro, N.C., with a load of freight at 0838 EST on a December morning in 1994. While en route, the weather deteriorated from two miles visibility at his destination to a half mile in fog. The pilot flew the localizer approach to the Wilkesboro Airport and missed the approach because he did not locate the airport or runway environment at MDA. The pilot then chose to try the ILS approach to Runway 24 at Hickory because it was close by. At the time, Hickory was reporting 800 feet overcast and one mile visibility in fog. ATC vectored the aircraft to the approach. The pilot told investigators after the accident, "I intercepted the localizer and never intercepted the glideslope. I tuned in the No. 2 nav and got the same response (no glideslope). I then converted the approach to a localizer and descended to the MDA."
Runway In Sight?
The pilot claims that he saw the 6,400-foot runway at MDA and attempted to land. With the gear down and full flaps, he touched down and retracted the flaps to aid in braking, but he realized that he could not get stopped on the remaining runway. In spite of heavy braking, the airplane overran the end and went through a chain-link fence, coming to rest on an embankment. The pilot received only minor injuries. Personnel working at the Hickory Flight Service Station reported seeing the airplane come out of the fog in a dive at the midway point of the runway. One of them stated that when he first saw the airplane, it was in a diving right turn toward Runway 24. He thought that the airplane touched down on the runway with approximately 1,800 feet remaining. He said that he did not believe that the airplane could be stopped in the remaining distance. The airplane disappeared behind some trees, and then smoke was noted in the area. Investigators could find no mechanical problems with the airplane. They pulled the avionics from the wreckage, including the ILS equipment, and had it bench-tested. No discrepancies were found.
A Convenient Airport
Did the pilot make a poor choice of an alternate airport after making the missed approach into Wilkesboro? Probably not, when you consider that the weather was reported as 800 and one at Hickory, well within a professional pilot's capabilities. The pilot was looking for an airport that was close because he had a load of packages aboard that had to be transported to Wilkesboro. The 27-year-old pilot was well-qualified for the flight. He held an ATP in multiengine airplanes and had 1,510 hours total flying time. He had 205 hours in the Cessna 402C, 505 hours of multiengine time, 120 hours of actual instrument time and 70 hours of simulated instrument time. In the 30 days preceding the accident the pilot flew 25 hours in the Cessna 402C, 16 of which were at night, and 21 hours in actual instrument conditions. So, why did the accident happen? The pilot claimed that it was because he never received the glideslope, so he flew a localizer approach instead. But that by itself should not have resulted in a runway overrun accident. Obviously, the pilot did not locate the runway environment until it was too late for him to get the airplane safely down on the ground. The current approach plate shows the MDA for the localizer-only approach to Runway 24 to be 1,560 feet, which is 371 feet above the runway. The missed approach point is the middle marker, which is 4/10 of a mile from the approach end of the runway. If these were the numbers in use when the accident occurred and the pilot saw the runway at the middle marker, then he needed more than 4/10 of a mile to get the airplane down safely on that runway. Keep in mind that an aircraft on the full ILS approach would be 171 feet lower at the middle marker if it was on the glideslope when it arrived there. At that height, it would be much easier to get the airplane on the ground and stopped safely on the runway.
Need It Sooner
Find A Real Alternate
Pilots often are fooled by widespread fog. In overrunning or warm frontal conditions, low ceilings may be so pervasive that a legal alternate will be hard to find. Oftentimes we are lulled into complacency by reports of low ceilings because the associated weather is benign. While we all would like to get into an airport that is reasonably close to our original destination, pilots should understand that it is not a good idea to expect that an alternate airport influenced by the same weather system as the destination will improve. We need to know where there is better weather -- where there is a suitable alternate -- and we should be prepared to go there when there is little hope of getting into an airport close to the destination. Oh, it is tempting to try, but the gas that gets spent on the attempt will limit an escape to better weather. As usual, the weather picture will influence our decision-making, and our management skills need to be at least as developed as our skills at flying instrument approaches.
Pilots should recognize that on most non-precision approaches, it's pretty tough to get down to the runway if you don't see it at or near the missed approach point. There is very little weather information in the NTSB report on this accident. We don't know if the weather was deteriorating at the time that the aircraft made the approach or what the forecasts for the area were. If the visibility had deteriorated below the one mile that was reported, it is possible that the pilot did not see the runway until it was too late to make the landing safely. Another possible scenario is that the pilot flew the glideslope, the weather at the approach end of the runway was much worse than reported and he didn't see the runway at DH. That is not unusual when early-morning ground fog is in the vicinity of a runway. If the pilot busted the ILS minimums and didn't see the runway until he was halfway along, long after he should have begun the missed approach, he would not report that to the FAA or the NTSB.
In another accident that occurred in October 1994, a Piper Aztec was destroyed when it collided with a stone quarry wall while it was on the ILS Runway 18 approach into the Clark County Airport in Jeffersonville, Ind. The pilot and four passengers were fatally injured in the accident that occurred shortly after midnight. In the afternoon of the preceding day, the pilot flew the airplane from Bowman Field in Louisville, Ky., to Dayton, Ohio, with the same passengers on board. Before departing Louisville, he called the Louisville Flight Service Station for a weather briefing. The FSS specialist told the pilot that a frontal system was moving in from the northwest and that it would be passing the Louisville area between eight and ten o'clock. IFR conditions were forecast for the flight on the way over as well as the return.
Shortly after 1900 EST, the Aztec pilot called the Dayton Flight Service Station for an update to his earlier briefing. At the time, Dayton was reporting 300 overcast with 1-3/4 in light drizzle and fog. Louisville/Bowman reported 1,900 scattered, 25,000 broken and three miles in fog. The pilot did not ask for any more information, nor was any given. He changed his departure point from a Dayton satellite airport to Dayton International. He had landed at KDAY earlier in the day because of the low weather conditions. Just before midnight, the aircraft approached the Louisville area and was handed off to the Standiford Approach Control. The controller got the current weather at Bowman and passed it along to the pilot. The report indicated that the sky was partially obscured with 1/2-mile visibility in fog. Bowman had only non-precision approaches to the airport, and the pilot elected to try the VOR Runway 24 approach. He told the controller that he would go to Louisville's Standiford Airport, his filed alternate, if he didn't get into Bowman. The controller responded that KSDF was below minimums, though he did not give him the actual weather. The pilot then decided that he would like to try the ILS 18 approach at Jeffersonville, nine miles northwest, if he didn't get into Bowman. The controller issued missed approach instructions.
After missing the approach at Bowman, ATC issued vectors to the ILS at Jeffersonville. He told the pilot, and another aircraft that wished to fly the Jeffersonville approach, that the Standiford weather was 800 overcast with 1/4 mile in fog. He then issued a vector to the final approach course, told the pilot that he was two miles from HAPPS (the final fix at that time), told him to maintain 2,500 feet until he was established on the approach and cleared the aircraft for the ILS approach. Just inside HAPPS, the controller cleared the pilot to leave the frequency, and there were no further communications. The second aircraft attempted to make contact with the Aztec several times but was unsuccessful. The aircraft had crashed into a stone quarry approximately two miles north of the airport. The wreckage was found at the base of a 60-foot high wall. It had burned on impact. The crash site was about 1/4 mile east of the localizer centerline. The collision point was at 480 feet MSL. The touchdown zone elevation for Runway 18 was 474 feet. The DH for the approach was 674 feet MSL with the local altimeter setting and 709 feet MSL with the Standiford setting. ATC radar tracking data showed that the aircraft passed over the centerline of the approach at 0030:31 at 2,400 feet. Thirty seconds later, the aircraft was at 2,100 feet to the left of the centerline. A course correction was made, then a constant heading was flown until the aircraft disappeared from radar at 1,100 feet at 0035:24. No low-altitude alerts were received by the controller and none were issued to the Aztec pilot.
The altimeter setting at Standiford was 29.97 and was issued to the pilot earlier. Investigators found the altimeter set to 29.78, and it read 580 feet. Did the pilot make the mistake of not setting his altimeter correctly? Did he believe that he was still 100 feet above the surface? We never will know the answer to those questions. The controller told the pilot that no weather information was available for Jeffersonville, and the pilot should have known about the DH restriction based on the altimeter setting. The first person at the scene of the accident said that the visibility at the quarry was only 10 feet. The pilot's logbooks never were located. According to FAA airman certification records, he held a commercial certificate with multiengine and instrument ratings. He had 1,041 hours 17 months before the accident occurred, with 15 hours in the Aztec and one hour as pilot in command. There was no information on the pilot's recent experience. This pilot was trying to find an alternate close to the destination with little reason to believe that the weather would be any better. Since he filed his return flight plan to Bowman in the afternoon at the same time that he filed to Dayton, he used Standiford as his alternate. But at some point Standiford went below minimums and was no longer eligible as the alternate. No Standiford forecasts were included in the accident report, so we don't know what the pilot would have heard had he asked for the forecast.
Both of these accidents point out the need not only to check the weather carefully before any IFR flight but to select real alternates with care.
About the author...
Brian M. Jacobson is a corporate pilot and aircraft owner who lives in White Lake, Mich.