Monday, January 28, 2019

Flying Luanda, Angola to St. Helena, South Atlantic Ocean, Part 2

Luanda, Angola to St. Helena

The flight to St. Helena on January 17 was the "big" one which we had been planning for months. At 1,186 NM ( 1,363 SM) it was not a particularly long flight by the standards of this trip and the enroute weather was close to ideal with clear skies at our cruise altitude favorable winds aloft.

No cruise level weather to worry about...

We conducted the flight at long range cruise (LRC) power setting which while slower (about 210 knots or 240 mph) is more fuel efficient.  By operating at LRC, unlike our flight to Easter Island, we had an alternate for St. Helena - the equally remote Ascension Island/FHAW 700 NM (805 SM) to the north. So, the enroute portion of the flight was not the big challenge. Landing at St. Helena was potentially a very big challenge.

As described in the prior post, St. Helena has the potential for significant wind shear and the lowest minimum descent altitude (MDA) on any instrument approach is 773 FT above the runway although the MDA on the most commonly used approach (RNAV LOC DME Rwy 20) is 867 FT above the runway. While we did have an alternate, we did not have enough fuel to execute multiple approaches at St. Helena and still go to the alternate with adequate reserves. So, if we missed one or maybe two approaches, we'd be diverting.

The good news is the UK Met Office has a dedicated forecaster on-site at St. Helena who can provide a highly specialized and personal weather briefing for any flight arrival. The forecast produced by the St. Helena Met Office goes way beyond the normal Terminal Area Forecast (TAF) we get back home. The forecast we received (generated specifically for our flight) the evening before launching for St. Helena is shown below.

I especially like the probability ratings provided in the forecast. All in all, this forecast was about as good as it gets at St. Helena. Low risk of low clouds or reduced visibility and not much chance of wind shear. The wind forecast is typical for the St. Helena airport which almost always sees moderate to strong south easterly winds. We got this forecast the evening prior to the flight day and also had a detailed telephone briefing with the meteorologist on-duty, Tim Baker.

We also made arrangements with Tim to get an update on the forecast the next day in Luanda before departing for St. Helena. Tim also agreed to give is an update enroute (via our InReach satellite communications device) just prior to reaching our "point of safe return" - the last point on the flight plan when we could turn around and go back to Luanda (although we would still have the option of diverting to Ascension Island).  On the ground at Luanda, Tim said there was no significant change in the forecast and we launched for St. Helena around 10:55 local time for the expected 5:30 flight (at LRC).  We even had a forecast for a nice tailwind along the route (about +15 KTS) which was great considering that the route normally has a much smaller tailwind component this time of year.

The departure from Luanda and climb to cruise altitude was all normal with good VHF communications. Luanda is a very large and spread-out city...

A while after reaching cruise altitude, the Luanda controller on VHF gave us a HF frequency on which to contact Luanda Oceanic for the rest of the flight to St. Helena (St. Helena resides in Luanda Oceanic airspace). We had a note in some of our preflight material saying HF communications with Luanda were very poor, so prior to leaving the VHF frequency we also got a direct dial phone number for Luanda Oceanic in case we could not establish communications on HF.  We never were able to contact Luanda Oceanic on HF (nor did we here any other aircraft successfully establish communication with them) and thus made all our position reports via satellite phone until establishing VHF communications with St. Helena tower about 250 NM east of the island.

Josh making a position report on the satphone...

After establishing VHF communications with St. Helena tower (almost an hour prior to landing), we  were cleared directly to the initial approach fix (UTAPA) for the RNAV LOC DME Rwy 20 approach which we had requested.

Based on our experience at Robinson Crusoe Island and the advice of Tim (the St. Helena metrologist), we planned to conduct the final approach at a four degree glideslope rather than the normal three degrees.  This would keep us a little higher on short final potentially reducing the time we would be exposed to any windshear which was typically reported at 400 FT above the runway and lower. Also, if we did encounter some wind shear, we'd have some extra altitude to "trade" for airspeed if needed.  Because the visual glide slope indicator (VGSI) for runway 20 is set for the more typical three degrees, we computed target altitudes at specific distances from the runway which would yield a four degree approach path.

As we started the approach, there were scattered to broken clouds, but almost as soon and we turned to the final approach (actually offset five degrees, so not exactly aligned) on the localizer, we glimpsed the runway through breaks in the clouds. Below about 1,000 FT above the runway, we were in the clear and kept focused on maintaining the correct glidepath to the runway. The glidepath to runways perched on a cliff like this one can be difficult to "eyeball," so we kept track of our computed altitudes for the four degree glidepath. As expected, the visual glide slope indicator showed us as high (four white lights) since it was set for three degrees.

As we got close to the runway (below about 500 FT) we encountered some light turbulence, but nothing bad. On very short final (within about one-half mile of the runway), we encountered some light wind shear in the form of sinking air. I added a little power to compensate and also lowered the nose a bit trading some altitude for airspeed. As a result, we intercepted the normal three degree glidepath on very short final which was fine...that was why we came in a little steep.

As reported in this post, by a remarkable coincidence someone on the ground made an excellent video of our arrival (have posted both of these video before, but they are so cool to me!)...

YouTube link:

And Becky made an excellent video compilation of the video from the ground and out both sides of the plane from inside (also posted previously)...

YouTube link:

The landing worked out well and we turned off onto the ramp (video below taken by the airport manager)...

YouTube link:

As mentioned previously, the St. Helena airport, which is owned by the St. Helena government, has had some less than flattering publicity over its short life. The government saw our flight as a bit of positive news and arranged for the Governor of the island, Lisa Honan, to meet us on arrival for a short conversation and some photos.

The government press office later interviewed us and did a press release that was published in the local newspaper.

For a short period we were fairly well known on the island. A couple of folks even recognized us as we were touring around for the next couple of days. I hope our flight did something in a small way to increase confidence in the future of the airport. If even a relatively small plane like ours can make a routine flight to the island, hopefully that helps show that the airport has the potential to be used more frequently and for a variety of purposes.

So, that is the story of the flight to St. Helena. Two days later Josh and I spent the afternoon at the airport getting a "behind the scenes" tour of the metrology office and control tower which I will report on in the next post.

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