Ballooning & floating?

Probably the most common comments I get from student pilots – and quite a few experienced pilots too – are about their perceived skills needed to land a light sport/recreational aircraft. In many cases, pilots make comments like: “I pulled back on the controls to flare and the aircraft just ballooned” or “it just seems to float and float along the runway; it just doesn’t want to land”.

Both of these events when landing an aircraft – ballooning and floating – have their own dangers for the pilot, which if not anticipated and handled correctly can result in a bent aeroplane…or worse.

So here are a few tips on how to get it right.

In simple terms, almost all balloons and floats during landing are caused by excess speed over the landing threshold. Unfortunately, many instructors have a habit of telling their students to add 5 or 10 knots to their approach speed ‘for safety’. In reality, in light sport aircraft in ‘normal’ conditions, they are often actually reducing the margin of landing safety by doing so. And this habit of adding speed to the book figure becomes instilled as a very hard-to-break habit. My own pilot training, now many many years ago, involved adding approach speed in certain circumstances and, even now, I have to fight the impulse to add speed when landing in the A22LS Foxbat and A32 Vixxen.

Let’s go ballooning
So, what’s wrong with more speed? There are two main reasons but first, remember light sport and recreational aircraft are very low weight (read: low inertia) aircraft. So, like a small car, these types of aircraft will change direction much more quickly than a limo, a ute or a truck. Not that I’m suggesting your average Cessna/Piper etc are trucks…. As a result, when landing, the controls are much more effective than bigger GA aircraft. At only slightly faster speeds the controls are even more powerful, so if you are too fast when you pull back to flare, the aircraft will not just flare, it will start to climb again, even with the engine at idle. This is called ‘ballooning’. When you go ballooning, the impulse is to push the nose down to reduce the sudden climb. Unless you are very quick (and/or experienced) you’re likely in for a bent nose leg and/or busted propeller. Another alternative, just holding back the controls during the balloon, can result in a stall from an ‘unsuitable’ height above the runway, leading to a (very) heavy landing, which could damage the landing gear or worse.

How about a bit of floating?
Next reason why too much speed is dangerous: even if you flare correctly without ballooning, the aircraft is still going too fast to land. Instructor: “Just try to skim the runway; don’t let the aircraft land; try to keep it flying as long as you can, slowly pulling back on the controls until the aircraft slows and the main wheels touch down”. This is all absolutely fine, unless you are carrying excess speed, in which case you’ll end up flying a long way down the runway before you touch down. And skimming along the tarmac (or grass) at relatively slow speed for a few hundred meters at just a few feet of height is tricky enough for an experienced pilot, let alone a novice. Throw in some cross wind, and/or a gust or two, and the risk of disaster rises exponentially! After a period of ‘skimming’ without landing, there is a huge temptation to let the nose drop a bit (or worse, push it down), just to get the wheels on the runway, and this can have two potential results: (a) because you’re still going too fast, the nose wheel touches down first and you’ll bounce/balloon, or (b) the impact will bend the nose leg and maybe bust the prop – if you’re lucky.

There are remedies for both ballooning and floating after they start but the easiest solution is not to let them happen at all!

Calculating the correct threshold speed
Which is where we get back to speed. There’s a GA rule of thumb about landing speed over the threshold. This says you should aim for about 1.3 times stall speed in landing configuration. As an example, with a stall speed of 45 knots the aim is (technically) 58.5 knots over the threshold – which is usually rounded to 60 knots. With low-inertia light sport aircraft, which have lower landing speeds, it’s probably safer to go for about 1.75 times stall speed, as wind gusts can be a much higher proportion of approach speed. So, for a stall speed of 28 knots (A22LS Foxbat) the threshold speed should be about 49 knots – which is exactly what the pilot manual gives. Note – this is 20 KNOTS above the stall speed!! If you come in at 55-60 knots over the threshold, you are flying about twice as fast as the stall speed – no wonder the aircraft is difficult to land!

What a drag
There are big differences in drag between aircraft. And drag affects how quickly the aircraft slows down when you throttle back for landing. The more the drag, the quicker the aircraft will slow down and vice-versa. To some extent, high-drag aircraft are easier to land than their more slippery siblings. As you cut power and round out to land, they will slow down more quickly, so if you are a few knots over the correct speed, they will help you out by slowing quickly. However, the more slippery the aircraft, the more accurate you need to be with the threshold speed; this is because if you are faster than you should be, the speed will not wash off quickly and ballooning and floating become much more likely.

As a comparison, our A22LS Foxbat is much much draggier than the A32 Vixxen. This is clearly evidenced in the fuel economy and cruise speeds. While the book figures for landing threshold speeds are much the same at 49 knots, coming in at 55 knots in the Foxbat will still allow you a reasonably easy landing. Try it in the Vixxen and because of its low-drag airframe, you’ll probably do a lot more floating. Add yet another 5 knots ‘for safety’ and even the Foxbat will take a while to land and the Vixxen will take you all the way down the runway into the fence at the end.

Landing weight
There’s an important additional piece of information needed here – the landing weight of the aircraft. All manufacturers quote stall speeds at maximum gross weight – for light sport aircraft, this is 600 kgs. If the stall speed is 28 knots at 600 kgs, it will be noticeably slower at (eg) 450 kgs actual weight, which in an A22LS Foxbat equates to the aircraft with one pilot and 50 kgs (70 litres) of fuel. In fact, it could be as much as 3-4 knots slower. Re-calculating the approach speed for this weight: (eg) 25 kts x 1.75 = 44 kts.

Hopefully, instructors  teach their students properly about the difference weight can make to stall – and thus landing – speeds. This is particularly important for light sport aircraft, where the pilot, passengers, fuel and baggage make up a much bigger proportion of the weight and therefore have a much more significant effect on speeds than heavier GA aircraft.

Wind
Finally, a point about wind. I’ve often heard it said you should add 5-10 knots to your approach speed if the wind is across the runway and/or gusty. The idea being that if the wind suddenly drops during your approach, the aircraft is still going fast enough to keep flying above stall speed. In heavier GA aircraft, this may well be valid, as using the throttle to regain speed to arrest the momentum of a sudden descent takes time. However, modern light sport aircraft are much more responsive to throttle than their older GA counterparts, so I would never add more than 5 knots to the ‘book’ approach speed in a cross or gusty wind and use the throttle to stop descent quickly if a sudden drop occurs due to a gust.

In summary – read the pilot manual for your aircraft to check the threshold speed for that specific type – do not rely on rules of thumb, like “all aircraft are OK at 60 knots” down final and over the threshold. If the manual gives 49 knots at gross weight stick to it and – if it’s a light sport aircraft – even a bit slower if you do not have a passenger and/or lots of fuel. If you don’t stick to the book speeds, you are looking for trouble and for sure, you’ll end up ballooning or floating and sooner or later you’ll bend something. Hopefully, not yourself or your passenger!

AeroTV and Aeroprakt A22LS

dennis-at-delandAero-News Network Inc has published a short review of the A22LS (Foxbat) on their YouTube channel AeroTV. Headlined ‘Versatile AND Practical – The All-Seeing Aeroprakt A-22 LSA’  AeroTV’s Tom Patton interviews Dennis Long, Aeroprakt’s USA dealer at the recent Deland Sport Aviation Showcase, held in Florida each year.

The video includes some rather old flying footage of an early Australian A22L, plus some newer video of a glider tug A22LS at Benalla in Victoria.  The report gives Dennis a great opportunity to describe the aircraft and its capabilities – which he does excellently! I must remember some of the phrases he uses to use myself at the upcoming Avalon Airshow. Particularly coming to mind are: “…just the best handling light sport on the field.” And: “…taking off on gravel or sand, it does a very fine job of that because the nose comes up right away and you’re balancing just like a taildragger.”

God job, Dennis!

A22LS Foxbat – ‘long leg’ option

long-leg-panel-01Aeroprakt Limited has recently announced the availability of a factory-installed option of a revised instrument panel with cut-outs along the bottom edge to help accommodate those pilots and passengers with long legs – see photos.

Although I am 1.88 metres (6′ 2″ in imperial) tall, I have never found a problem with the leg room in either the A22 Foxbat or A32 Vixxen aircraft. However, a friend, who is exactly the same height as me, has often complained about the lack of knee room for him in the A22 Foxbat. Apparently, I have a longer body and shorter legs; he has a shorter body and longer legs – one reason I advise all potential aircraft buyers to actually sit in the aircraft on their shortlist, to check knee/leg room and head clearance. A particular height or body weight does not guarantee a comfortable fit even if an apparently identical size friend fits perfectly!

long-leg-panel-03Many thanks to Aeroprakt, therefore, for introducing this ‘long leg’ option on the A22 Foxbat. The pictures clearly show the panel cut-out modification, which is only available on stick control versions of the aircraft. As yet, this option is not available for the A32 Vixxen, neither is it easy or inexpensive to retro-fit to existing aircraft as there is a significant change to the instrument panel support structure.

AVweb flies the Aeroprakt A22LS

avweb-dennisOur very own Dennis Long of Aeroprakt USA takes AVweb’s Geoff Rapoport for a flight in the A22LS at Sebring, Florida during the recent Sport Aircraft Expo.

Great video Dennis – not too sure about the colour scheme…

AVweb describes itself – rather modestly – as ‘the world’s premiere independent aviation news resource’ and they certainly have a wealth of interesting content and aircraft reviews. Have a browse.

One of my personal favourites is Paul Bertorelli’s rather sarcastic comment on the huge patterns – ‘circuits’ to us non-USA pilots – which instructors use when training. It’s one of my personal gripes at my home airfield, where sometimes club aircraft doing circuits seem to set out on scenic flights along the bay during the downwind leg. I was taught, admittedly by military instructors, to take-off, climb to 500 feet AGL, then make a turn and climb cross-wind to 1,000 feet AGL, then turn downwind. I fully accept that a Foxbat or Vixxen will get to these heights much quicker than a C150 or C172. However, even when I’m doing circuits in my relatively leisurely Interstate Cadet, the club Cessnas are usually way outside of me. It makes circuits a real chore as it’s very bad manners to cut inside. And, as Paul comments, it tends to train pilots to do long, straight in approaches, using engine to ‘drag’ the plane in to the threshold, which is not always possible in ‘real’ life.

As usual, either click the picture to take you to the A22LS video, or click here: AVweb flies the Aeroprakt A22LS

Aeroprakt A32 1,000 nm ferry flight

ido-shaun-at-emeraldMy colleague Ido Segev and his friend Shaun just got home from an almost 1,000 nautical mile ferry flight of a new shiny Ferrari red Aeroprakt A32 Vixxen, registered VH-ACL, to its new owner Will Graham.

The aircraft is fitted with a Dynon SkyView system, including a 2-axis autopilot, transponder and fuel computer. In addition to the standard dual-watch VHF radio, the aircraft also has an 80-channel UHF radio, operating through the headsets.

ido-shaun-ferry-02Their flight took them from Moorabbin Airport, near Melbourne, via Temora and Parkes in New South Wales, to an overnight stop at St George in southern Queensland. Most of the flight was made at 8,500-9,500 feet AGL, which at times translated into a density altitude of over 11,000 feet. Said Ido: “Even at 7,500 feet were were still climbing in excess of 500 feet a minute – not bad with two of us, full fuel, luggage and some spare parts on board.” The next day, the weather wasn’t so kind, with strong headwinds and a 2,000 foot cloud base. Nevertheless they made good time and arrived at Emerald, Queensland, before lunch, after a short wait at Roma while some weather passed through.

Total flight distance was about 950 nautical miles with and average ground speed of slightly over 95 knots. Average fuel burn was a shade under 17 litres an hour. In metric fuel economy terms, that’s about 10.3 litres per 100 kilometres – not bad for an average speed of over 175 kilometres an hour! Ferrari and co, eat your hearts out!

Analogue dials vs digital screens?

ad-panelI’m asked a lot about the pro’s and con’s of digital flat screen ‘glass’ cockpits for the Foxbat and Vixxen aircraft. The quality and reliability of LSA/recreational digital instruments has improved immensely over the last 5 years and, although they are not inexpensive, they actually represent reasonable value for money – particularly when compared with their GA-certified counterparts.

Personally, I am a great one for old ‘steam’ gauges – easy to see in all lights, relatively simple and usually reliable. Although I must agree that reliability of the current crop of ‘glass’ cockpits is not an issue. And digital screens do have some big benefits – visual and audible warnings if/when any set parameter is exceeded; an almost infinite number of ways to customise the look of the information; a high degree of modularity – meaning you can add bits like a fuel computer or an autopilot at a relatively reasonable cost at a later time; and, last but not least, most digital panels have a datalogger which enables you to review flight and engine information from previous flights. This can be particularly useful – as we have found – when analysing ‘incidents’ and ‘accidents’ which the aircraft may have experienced.

However, a particular question has been raised a couple of times recently, by pilots/buyers with quite different aviation backgrounds – one, a very experienced airline pilot, the other a novice student pilot. The question was: ‘Do digital screens tend to focus the pilot inside the aircraft?’ And, I suppose by implication, that if they do, this is a bad thing, where sport and recreational flying is so much about what’s going on outside the aeroplane – ‘see and be seen’ and all that.

The point made by the airline pilot was that what’s going on outside a commercial jetliner is almost (but not always!) irrelevant. The screens provide all the data you could possibly need to negotiate the aircraft from wheels up on departure from airport A to wheels down at airport B. If such a pilot decides to buy an LSA with a digital panel they will, so it goes, be more likely to be looking at the screen a much higher proportion of the time than looking outside.

The point being made by the ab initio pilot was that while you’re learning, you can become transfixed by the figures on the screen. Let’s take digital speed readouts – eg a pilot manual approach speed of 57 knots  is something you have to concentrate on much more than a wavering analogue needle, which points somewhere (on average) between 55 and 60 knots. So you try to stick to the magic digital 57 knots to the exclusion of some outward attention.

It’s all a far cry from the days when a slip ball was the most prominent instrument in the aircraft, and the only compulsory gauges were a compass, an airspeed indicator and an altimeter. With maybe engine rpm and oil pressure if you were lucky!

So having heard these points of view from pilots from very different perspectives – what’s your view? Do digital screens tend to focus the pilot inside the aircraft, to the detriment of good external observation?

Aeroprakt A32 incident at Moorabbin

a32-damaged-moorabbinOn Sunday 8th January 2017, an Aeroprakt A32 Vixxen – registered VH-VBQ – was involved in a much-publicised landing incident at Moorabbin Airport. The final landing was recorded on video by a Channel 9 helicopter, as well as by several people on the ground.

As I understand it, briefly, here is what happened.

The aircraft was on hire to a pilot, who was not an instructor, to go for a local flight with a friend. Conditions at Moorabbin Airport recorded an increasingly gusty cross wind. When the aircraft returned to land, a gust caught the aircraft and it landed heavily on the nose wheel and right side main gear. The plane bounced and, in my opinion correctly, the pilot initiated a go round. However, it quickly became obvious that the nose landing gear was bent and also, to a lesser extent, the right main gear.

An emergency was declared and the aircraft circled nearby while the airport was closed and a foam blanket laid at the end of runway 17R – the most into-wind runway and also the closest to apron and emergency services access. The pilot made a couple of trial approaches to this runway before making a final approach and successful landing. During the touch down, as might have been expected, the nose leg collapsed completely and the aircraft slid to a halt just beyond the end of the foam layer. The pilot and passenger were not injured and were able to exit the aircraft quickly. There was no fire and the aircraft is currently being assessed for damage before repair.

The pilot had relatively low flight time recorded on the A32 and is to be congratulated on making a successful emergency landing in the conditions, which not only included a gusty cross wind but also limited rudder control due to the damaged nose leg, which is control-rod connected to the pedals.

Afternote – news programs and publications variously reported the following: ‘the nose wheel failed to lock into position’; ‘the front wheels of the plane malfunctioned’; ‘the pilot circled the runway numerous times while he tried to fix the issue’  and ‘the aircraft made a nose landing’. I would like to re-assure customers and owners of the A32 Vixxen that (a) it is not built as a retractable gear aircraft, and (b) there is no inherent problem with the nose gear. But if you bang anything hard enough, it will bend, and it’s quite difficult to fix the bent gear while you’re flying the aircraft.