[More flying detail for aviation geeks...]
Tuesday, November 27, 2018
By Monday evening, November 26, we had our permits in hand for the "big" Santiago/SCEL to Easter Island/SCIP flight with a fuel stop at Robinson Crusoe Island/SCIR (2,030 NM or 2,340 SM). The wind and weather forecast for Wednesday, November 28 looked ideal.
We got very lucky with the winds as the forecast for November 28 was essentially net zero wind component at FL300 (30,000 FT, our planned cruise altitude). Based on historical data, the 80% worst case value for that day is a 34 KT headwind, average is 25 KT headwind, and 80% best case is a 14 KT headwind. So having zero wind was a real outlier on the good side. We had allocated four days to just sit and wait for an acceptable wind forecast (more if needed), but got lucky and had excellent winds the first day of our window. So, Tuesday morning (November 27), Josh and I started working on the final details assuming an early Wednesday (November 28) morning launch.
After sleeping in a bit on Tuesday morning, Josh and I headed over to the dispatch/operations office at Aerocardal FBO where Jose G was helping us get all the details finalized. He double checked our flight plan reminding us the the special procedures for a flight to Easter Island requires computation of a "critical point" and inclusion of that in both in terms of elapsed flight time and latitude/longitude coordinates in the remarks section of the flight plan. It was not clear to us if the "critical point" was the Equal Time Point (ETP) or the Point of Safe Return (PSR). We calculated both and decided to include the ETP in the flight plan and got no questions from ATC.
Hanging out in the Aerocardal operations office for most of the afternoon also allowed us to chat with several Aerocardal pilots that operate to Robinson Crusoe Island regularly. Aerocardal has a small tourist business flying people to Robinson Crusoe Island in Dornier 228 aircraft and organizing several days of touring the island. The pilots that had experience at Robinson Crusoe gave us good advice, although nothing significant that we did not expect from our prior research. But, it is comforting to know you did not miss anything. We even talked to one "elder statesman" Aerocardal pilot (must have been in is 80s) that said he first landed at Robinson Crusoe in 1973 before there was an airport! He just landed on the flattest looking field he could find. Obviously he was in a plane designed for rough and short field operations (although I don't recall the exact type he mentioned).
Confident that all the details had been handled and we were well briefed, Josh and I headed back to the airport hotel for a good night's rest in preparation for an early departure the next day.
Wednesday, November 28, 2018
We arrived at the Aerocardal FBO before sunrise and got the plane ready for departure.
We had had the plane fueled to maximum capacity the afternoon prior, but fuel expands and contracts with temperature. The energy content of the fuel is based on the mass, not the volume. Although our fuel tanks have a fixed volumetric capacity of 403 gallons, if fueled in warm temperatures, the tanks will hold less mass of fuel than at cooler temperatures. Practically speaking this means if you fuel a plane to the absolute top of the tanks at, say, a 30C OAT (outside air temperature) and then look into the tanks the next morning at a 15C OAT, you will find the tanks are no longer completely full and a few more gallons can be added. Given the criticality of fuel on the trip to Easter Island, we asked the ramp folks to top-off the tanks again this morning in the cooler temperatures. They got about seven more gallons in which is only about 12 minutes more flying time, but on a trip like this one you want every small advantage you can get.
The all important ATC approved flight plan from Santiago to Robinson Crusoe Island...
And the equally important approved flight plan from Robinson Crusoe Island to Easter Island (recived before departing Santiago)...
After getting our clearance and final pre-flight checks, we started-up and taxied to the runway. We were hoping for a quick taxi and immediate take-off to conserve fuel, but the morning airline departures from Santiago had already commenced and we arrived at the end of the runway #3 behind several big jets for take-off. After about a 10 minute wait we were cleared for take-off on a beautiful clear morning just after sunrise...
Youtube: https://youtu.be/qVuLeSFjmDE
Leaving the Chilean coast we were told to contact Santiago center on HF frequency 10024 (Khz).
HF frequencies (generally 5-30 Mhz) have the big advantage of being able to reach long ranges (sometimes more than 1,000 NM) as compared to the VHF communications frequencies (120-135 Mhz) we typically use at home. HF can attain those great communication distances because the signal can "bounce" off layers of ionized atoms in the ionosphere (more detail here). VHF is strictly line-of-sight which means ranges of around 100-150 NM at the altitudes we use in cruise. However, HF has the big disadvantages of: 1.) lots of static; and 2.) inconsistent reception quality. VHF is essentially static free and if you are in range is usually rock-solid reliable. HF always has static and sometimes it takes multiple attempts to establish communications. In some cases HF communications can't be established at all and one has to revert to back-up plans (trying different frequencies, relaying through other higher flying airplanes, or using a satellite phone) or you just wait a try again every few minutes.
HF is also sensitive to the position of the sun in the sky with higher frequencies working better when the sun is high in the sky and lower frequencies working better at dusk/dawn and at night. In most parts of the world we have traversed using HF, the ATC centers vary the frequencies they use based on the time of day. For some reason Santiago seems to use 10024 Khz all the time. Knowing this might be an issue, before being transferred from HF from the VHF frequency, we asked for a back-up direct dial phone number for Santiago Oceanic and it turns out we used it for the whole trip to Robinson Crusoe Island (although that amounted to only a couple of phone calls).
Our preflight weather analysis (with the help of weather guru Jerry S) indicated we'd have about a 2,500 FT broken ceiling at Robinson Crusoe Island with winds of 15-20 KTS almost right down runway 14. Once we got close to our TOD (top-of-descent) approaching Robinson Crusoe, we called Santiago Oceanic (on the sat phone) and told them we were ready for descent. They told us to descend to 5,000 FT and that our flight plan was cancelled below 6,000 FT (the floor of controlled airspace). We started the descent from FL300 (30,000 FT) and once through 6,000 FT we were in the clouds and on our own. No ATC looking over our shoulder.
We continued the descent planning to go no lower than 1,000 FT over the ocean which we could verify using the radar altimeter (since we did not yet have an altimeter setting for the area). Around the predicted 2,500 FT we broke out of the clouds and saw Robinson Crusoe Island right in front of us. It was a nice sight.
Thanks to Becky and Josh for this video of the arrival into Robinson Crusoe Island...
Youtube: https://youtu.be/2Zd6CDD-IVc?t=109
Carolyn made a video of the landing and taxiing-in out the right side window. You can see how the runway goes right to the edge of the 400 FT cliff over the ocean...
Youtube: https://youtu.be/LLsla7m5SnU
While there was no glideslope (visual or electronic) for this runway, I made a list of altitudes and distances to the runway that would keep us on a four degree glideslope to the landing zone. The end of the runway is more than 400 FT above the ocean and thus the opportunity for a visual illusion if just "eye-balling" the approach is significant. Thus I wanted the back-up with the altitude checks. The Aerocardal pilots that operated at Robinson Crusoe suggested a slightly steeper than normal approach to help reduce the impact of turbulence that can be created by the winds flowing off the mesa over the cliff to the ocean. Thus, the four degree glide slope rather than the more common three degree.
By some stroke of luck the landing worked-out pretty well. You know the old saying about blind squirrels and nuts.
Once parked on the small ramp at Robinson Crusoe, Marcelo, the person coordinating delivery of fuel on the island, immediately appeared in his truck with the two precious barrels of fuel. There were some initial problems getting their electric fuel pump to work properly, but after about 15 minutes that problem was solved and the fueling went quickly. Just to make sure we were absolutely full before departing for Easter Island, we carried two five gallon cans of fuel with us in the plane. After emptying the drums, Josh and Marcelo's crew put every last drop they could from the cans into the tanks using almost all of it. By luck or good planning one, we had just about the perfect amount of fuel on-hand.
Some photos of the fueling process with Josh carefully monitoring everything while I went to the "tower" (AFIS office) to get the flight plan for the next leg to Easter Island...
Some general scenes around this most unusual airport. The airport area also served as an entrance to a national park. Our flight was quite a curiosity for the small group of people that live there...
The small terminal building was fairly new and had all the basics to handle the tourists flights that arrive there a few times a week...
I went up to the "tower" (the AFIS office) which was fairly well equipped for such a low volume airport...
The AFIS person on-duty put me on a direct line to Santiago Oceanic to get our clearance for the flight to Easter Island. The controller first wanted to confirm we had an HF radio and were RVSM approved. I responded affirmatively to both and then he wanted to give me a second phone number to reach them in case we could not reach them on HF. Evidently the have a landline phone (the number we used enroute from Santiago to Robinson Crusoe), but they also have a battery powered sat phone for additional back-up. Good idea. He gave me the second phone number and asked me to test it prior to departure from the plane which I did successfully.
As the Santiago Oceanic controller seemed to be wrapping-up our phone call I asked about our IFR clearance to Easter Island. He said something along the lines of "Oh yea, cleared as filed maintain FL300." I read that back and then asked for the "void time.' Back home when getting an IFR clearance from an uncontrolled airport they always give you a void time which means if you are not airborne by that time your clearance is void and you cannot depart. ATC keeps all the airspace around your departure airport clear of other traffic and they don't want to do that indefinitely, so they give you a time limit.
After I asked for the void time, the controller paused and then said "Are you leaving sometime today?" I said, "yes" and he said "That is fine...there is no one out there on your route anywhere near your altitude all day, so depart whenever you like."
A clear reminder that we were headed off into some remote territory.
I thought I could get this story into two reasonable length posts, but this one is already too long so I will finish with the story of the flight from Robinson Crusoe to Easter Island in a few days. Tomorrow (Monday, December 10), we depart French Polynesia for New Zealand with an overnight stop in the small island nation of Niue.
