This Christmas eve we will kick off a new series of events called World's Challenging Approaches.
In World's Challenging Approaches, we will circle round the globe and try to land at some of the toughest airports.
Leg 1
For the inaugural flight, I've decided to chose our well known Innsbruck Airport (LOWI), because many of us have visited there many times and we get to see a splendid sight of the Alps along the way.
LOWI is in a deep valley which runs east-west roughly. At a more detailed look, you see that exactly at Innsbruck the valley bends to a "smile". This narrows the options to reach the airport without hitting a mountain: For large birds, only east and west are possible. For VFR, two more add to it: from the North via Seefeld (NOVEMBER route) and from the south (BRENNER-SIERRA).
Runways: 08 - 080 - 6560x147 ft - 1907 - MSL - Concrete - visual 26 - 260 - 6560x147 ft - 1894 - MSL - Concrete - non prec.
1. LOC DME EAST approach ... is the most common approach into Innsbruck. See the LOC DME East chart. This approach is fairly easy, but it's like getting a thread into a needle's hole: Don't miss it.
Be aware, that the phrase LOC DME East means something: The localizer OEV leads to the runway, but with a 5° offset to the north - it's NOT an ILS and you can't land with it! Also, the primary means for descent is the profile as shown in the charts. Additional descent guidance is given by a glideslope. It is intended to bring you close to the airport, but then you have to disconnect AP and land visually. See the Visual Approach Chart for details. When cleared LOC DME East approach, you leave RTT NDB at 9500ft with 210° and grab the OEV (111.10) localizer and glideslope. Strictly, the glideslope is only an indicator and you have to follow the altitude limits on the chart, but you might as well do the other way around: grab the glideslope and monitor altitude and OEV DME. Why that? Because in real life, the beacon could be mislead by reflections from the mountains. When established on the LOC, continue descent on the glideslope, slow down to reach AB NDB at 160kts or less. Be prepared to fly either straight into 26 or circle for runway 08 - see below.
Go-around is difficult, as there are mountains everywhere but behind you. You have to climb with max rate at approach course. At 1nm DME OEV (that's one mile before the airport) turn tight left (1600m radius, that is roughly 25-30° bank). In real life, pilots must fly this by hand and so should you (autopilots usually don't turn that steep and sometimes even turn the wrong way).
a. Runway 26 for landing This is the easy way, and still many pilots screw it up: Strictly, AB NDB is your MAPt (Missed Approach Point), so you have to go around if you are not cleared to land or informed about late clearance. Anyway, you disconnect your AP now and continue visually. As the runway is some degrees banked to the right, you fly a dog's leg over Innsbruck (left, then right) to align with the centerline. If you don't see the runway: go around! Fly the go-around manually or end up in the Sistrans Airmen's Cemetery. The one most common mistake here is to think that OEV is an ILS aligned with the RWY. Those folks smash some GAC aircraft on the apron and hit the terminal building.
b. Circling Runway 08 for landing The other option is a visual circling approach to runway 08. Before AB Locator: set your radar altitude warning to 400ft - gives you a chime when you get too low. Prepare to level off at 4000ft altitude for the downwind circle (that will be the case shortly before AB NDB). Fly the OEV localizer and glideslope until AB Locator. Set your plane to approach (speed, flaps) At AB Locator: You disconnect the AP and level off at 3700ft to 4000ft MSL - the chart is only a guideline, fly visually! After AB, you turn left (230° is a guideline - fly visually!) which leads you towards INN NDB. The route leads you over the green fields on the left side below the Patscherkofel. Scary? Watch your altimeter and stay between 3700 and 4000ft. Caution: From here on, go-around is right around! The 400ft "minimums" warning will prevent you from getting too low. Before reaching INN NDB (where you would hit trees) turn left for the right downwind past the airport, passing INN NDB on the right hand side. On downwind, Prepare your plane for landing (speed, flaps, gear) and coninuously check your altitude: 3700-4000ft or you hit the church tower of Aldrans. Boy, this is a catholic country, they crucify you if you damage it! Watch OEV DME (OEV is directly at the airport) decrease below 3nm and increase again as you fly past the airport. When OEV DME has risen again to 3.5nm (that just about when you say "ooh sh.." as the mountain ahead approaches), do a sharp right turn and smoothly descend into the valley - don't be too shy, but don't dive. Perfect would be: Start the turn firmly, and when you have settled in the 25-30° bank and descend smoothly (you still have a hill below you). When you have completed a 90° turn, look to the right for the runway (the hill will most likely be behind you now), turn and descend firmly for the centerline. With a bit of training you find yourself head on runway 08 for landing.
Common mistakes are:
First too low: Pilots leave the AP with ILS on and get too low at AB. Disconnect early to level off at 3.700 (better 4.000) ft.
AP on: Pilots fly the circle with heading and v/s mode of the Autopilot and hit the Patscherkofel Airmens' cemetery. Fly by hand, this is what pilots are here for.
Then too high: Pilots don't descend at the final turn and end up too high, desperately dive and land way too fast. You have to turn and descend (again, by hand). It is a nice, gradual descent - no need for a vomit-dive. If you are too high, go-around or (very smart!) another visual circle over AB NDB.
or too fast: If you forget to prepare your aircraft for landing on downwind (when the airport is to your right), you won't have another chance, as you have to descend firmly on final. If that happens to you, go around or request another visual circle.
Special LOC DME East approach ... is a special performance for bad visibility: It starts the same as the normal LOC DME East approach, but you continue to fly the LOC and glideslope past AB DNB to the outer marker, where you have about 3.500ft and then do the circle (the dotted line on the visual approach chart here). You need to have a special performance (small) plane for this. In real life, this is rarely used, because with such bad visibility, aircraft are normally cleared for runway 26, unless there is strong easterly wind. When easterly wind is strong, bad visibility is unlikely.
