The aer­o­batic

Fight­ing fires from the air is an ex­treme form of avi­a­tion – and not for the faint-hearted

Pilot - - CONTENTS - Words Filipe G J Con­ceição Silva Pho­tos An­dré Diogo

To most Brits, Por­tu­gal is syn­ony­mous with hol­i­days: hot sum­mers, good food and wine. If you are into avi­a­tion, how­ever−as one can as­sume if you are read­ing Pi­lot− Por­tu­gal would def­i­nitely not come top of the list as an ex­cep­tion­ally aero­nau­ti­cally-in­tense part of the world. But there is one as­pect of avi­a­tion in Por­tu­gal that does not ex­ist in the UK: aerial fire­fight­ing.

Due to a com­bi­na­tion of hot and dry weather, a vast amount of wood­lands, and some strange psy­cho-so­cial pe­cu­liar­i­ties (which I shall not dis­cuss here), from June un­til mid–oc­to­ber hun­dreds of wild­fires break out all over the coun­try. As re­cently as June this year a gi­gan­tic for­est fire had tragic con­se­quences. Around sixty peo­ple try­ing to flee in their cars were caught on the road when a fire storm ex­ploded, en­velop­ing all and ev­ery­thing in its way.

Aerial fire­fight­ing has been op­er­at­ing in Por­tu­gal for over four decades, us­ing both he­li­copters and fixed-wing air­craft. Canadairs and Fire Bosses are presently in ser­vice. I’m go­ing to de­scribe fight­ing fires with the Fire Boss, and some of the finer points needed to carry out the fire­fight­ing task ef­fi­ciently and safely.

The Air Trac­tor AT–802F Fire Boss was the first air­craft to be de­signed specif­i­cally for fire­fight­ing. Prior to that, there were only adap­ta­tions of crop-dusters or trans­ports, or even bombers. The first pro­to­type Fire Boss flew in 2003, and up un­til June 2017 close to fifty have been built. It can be trans­formed into a purely land ver­sion, the AT-802, with the same ca­pa­bil­i­ties in re­la­tion to fuel and wa­ter ca­pac­ity but with an in­crease of forty knots in the cruise (the large Wi­paire floats slow it down con­sid­er­ably).

Our Fire Bosses are sin­gle-seat, although there is a twin-seat ver­sion, and even an armed ver­sion for counter-in­sur­gency ac­tiv­i­ties. Its 1,400 litre fuel ca­pac­ity al­lows ap­prox­i­mately four hours use­ful flight time. The hop­per tank is ca­pa­ble of hold­ing 800 US gal­lons (3,028 litres) of wa­ter and can be adapted to carry fuel for long range ferry flights. While the tank can be filled with wa­ter on the ground, it is best known for its scoop­ing ca­pa­bil­i­ties whilst wa­ter-land­ing. It also has three tanks to­talling 300 litres that can be filled with foam to mix up in flight with the wa­ter for a bet­ter ex­tin­guish­ing ca­pa­bil­ity.

The Fire Boss is pow­ered by the ever-re­li­able Pratt & Whit­ney PT6-67F,

de­liv­er­ing 1,600 shp, and a five-blade Hartzell prop. It is al­ways flown VFR and is a to­tal ‘stick and rud­der’ air­craft that has to be flown us­ing stick and rud­der, like a glider−although it has a quicker re­sponse. In flight, con­stant rud­der-trim in­puts are needed for ev­ery small al­ter­ation of speed or power ad­just­ment. When you see it in the air, the per­cep­tion is that it is as small as any sin­gle-en­gined air­craft, how­ever once up close its di­men­sions are quite re­veal­ing. In fact it is the largest and heav­i­est sin­gle be­ing

pro­duced nowa­days, with a max­i­mum take­off weight of 16,000 lb.

Six Fire Boss am­phib­ian air­craft have been sta­tioned at three air­fields in the cen­tre/north of Por­tu­gal, pro­vid­ing quick re­sponse in­ter­ven­tion in case of fire any­where in the coun­try. The Por­tuguese Civil Pro­tec­tion Author­ity has quite an in­ge­nious set-up in place for these air­craft, as there are in­nu­mer­able dams, rivers and lakes all over the coun­try, which have been sur­veyed and ap­proved for wa­ter-land­ings and scoop­ing op­er­a­tions. When fires break out, for what­ever rea­son, they will usu­ally be within an ac­cept­able op­er­at­ing dis­tance from these many wa­ter-land­ing sites i.e. un­der fif­teen min­utes flight time from the fire, and on av­er­age less than thir­teen nau­ti­cal miles away.

From the first call with the co­or­di­nates, and in­clud­ing a quick brief­ing and eval­u­a­tion of the fire and wa­ter-land­ing con­di­tions, a fif­teen minute max scram­ble time is ex­pected−and usu­ally they are air­borne within eight min­utes.

The ideal way to op­er­ate is first for a pair of Fire Bosses (they al­ways fly in pairs) to take off and pro­ceed to the fire in its ini­tial stages and start smoth­er­ing it with con­tin­u­ous wa­ter-bomb­ing runs via repet­i­tive wa­ter-scoop­ing from the near­est dam or lake. Se­condly, a sup­port he­li­copter will ar­rive (Écureilles or Bells) with a wa­ter bucket and a group of five or six fire­men who will at­tempt to con­tain the fire as far as may be prac­ti­ca­ble.

The scoop­ing op­er­a­tion it­self is very dy­namic and stress­ful:

Fly fi­nal close to 80kt IAS with 20o flap and gear up (ob­vi­ously!) Touch­down close to 65kt Wait for a cou­ple of sec­onds to reach, on the wa­ter, 55/60kt

De­ploy the scoops via a trig­ger on the stick

Power up the en­gine, whilst keep­ing the trig­ger de­pressed un­til the spec­i­fied quan­tity of wa­ter is in the tank (800 US gal max), and main­tain hard stick back in the process, not ac­cel­er­at­ing above 65kt− quite a chal­lenge, as the air­craft in­sists on nos­ing down and adopt­ing an ‘I want to sub­merge’ at­ti­tude

Re­lease scoop trig­ger and very (very) gen­tly al­low the air­craft to go on to the step

Take off, nudg­ing the stick for­ward to al­low an in­crease to a safe air­borne air­speed.

An ex­pe­ri­enced pi­lot can achieve all this in less than a twenty-sec­ond wa­ter run. The C of G is al­ways within lim­its but the weight al­ter­ation in such a small amount of time is a hand­ful for any pi­lot and makes him break into a sweat quite read­ily. It is not un­usual for a pair of Fire Bosses to per­form twenty bomb­ing runs each on one fire in one mis­sion.

The sce­nar­ios that pi­lots some­times en­counter are not for the faint hearted, as wa­ter-bomb­ing runs are per­formed be­tween 60-90ft AFL (above fire level), ei­ther over or as close as pos­si­ble to the flames. If you fly much higher than this, the wa­ter could evap­o­rate be­fore it hits the tar­get. The Fire Boss is some­times taken into truly ‘in­fer­nal’ sit­u­a­tions with flames ris­ing over 100ft, and smoke thicker than fog, se­ri­ously ham­per­ing vis­i­bil­ity. Tur­bu­lence is usu­ally ex­tremely in­tense, in ad­di­tion to the windy con­di­tions that fires usu­ally cre­ate, es­pe­cially in moun­tain­ous ter­rain. With all of this, on top of the ca­coph­ony of com­mu­ni­ca­tions be­tween air­craft, chop­pers, and also with fire­men on the ground, a pi­lot can eas­ily be led into spa­tial dis­ori­en­ta­tion.

The wa­ter-bomb­ing runs are per­formed with 10o flap at ap­prox­i­mately 110-115kt IAS in a straight and level flight path, not de­scend­ing ex­cept in moun­tain­ous ter­rain

where ex­tra con­sid­er­a­tions come into the over­all de­ci­sion. The FRDS (fire re­tar­dant de­liv­ery sys­tem) can be se­lected to dis­pense a wa­ter flow of dif­fer­ent gra­da­tions, from a long and slow flow to a brusque and im­me­di­ate re­lease. In this lat­ter case−the most com­mon−the stick has to be pushed hard fully for­ward to stop the air­craft en­ter­ing a po­ten­tially dan­ger­ous and ex­treme nose-up at­ti­tude. In some sit­u­a­tions−usu­ally moun­tain­ous ter­rain− once a bomb­ing run is ini­ti­ated the pi­lot is com­mit­ted, and the wa­ter will be dropped even if he re­alises that it will not hit the in­tended tar­get area. If the wa­ter is not re­leased, the ex­tra weight and the rel­a­tively slow speed can eas­ily mush the air­craft into the ground as it pulls up. A few Fire Bosses have been lost in wa­ter-land­ing or scoop­ing op­er­a­tions but not in Por­tu­gal (yet).

Aerial fire­fight­ing is, not to put it too strongly, a dan­ger­ous ac­tiv­ity! It is per­formed close to the four el­e­ments: earth, wa­ter, air and fire. De­spite ev­ery pre­cau­tion be­ing taken−and all in­volved un­der­go­ing in­tense train­ing−when in­ter­ven­ing in for­est fires, close en­coun­ters with trees are not rare, as with moun­tain­ous ter­rain, there­fore some to­tal losses, ac­ci­dents or se­ri­ous in­ci­dents are to be ex­pected.

Fire Bosses in Por­tu­gal cur­rently op­er­ate from bases in Viseu, Vila Real and Proença–a-nova, with a to­tal of six op­er­a­tional air­craft and one re­serve. To give an idea of value for money, the price for one Canadair (an ex­cel­lent twinengine­d fire­bomber) would buy aprox­i­mately ten Fire Bosses.

Each base is manned, from early morning to sun­set, by two pi­lots, one me­chanic, and one op­er­a­tor who is re­spon­si­ble for as­sist­ing the me­chanic, turn-arounds, fu­elling, and fill­ing wa­ter tanks if scoop­ing is not used.

In 2017, our six Fire Bosses flew a to­tal of 2,025 hours, per­formed 9,620 wa­ter-bomb­ing runs, with an av­er­age elapsed time of eight min­utes be­tween scoop­ing point and fire. In to­tal 28 mil­lion litres was dropped on fires at a rate of 24,000 litres per hour.

Although it is a sea­sonal ac­tiv­ity here in Por­tu­gal, we have quite a mix of na­tion­al­i­ties who choose to fly the Fire Boss in our coun­try: Por­tuguese, Span­ish (Cata­lan, Basque, An­dalu­cian), Lithua­nian and one lonely Brit, who is also re­spon­si­ble for flight safety.

The Latin motto of our aerial fire­fight­ing ser­vice is Ser­vando Viren­tia Nostri Or­bis Ter­rarum which means some­thing like ‘Keep­ing our world green’.

Clock­wise from above: when fight­ing fires, the Air Trac­tor AT-802F Fire Bosses op­er­ate in pairs; CPA Chief Pi­lot Car­los Craveiro (left) and au­thor Filipe with the two-seater used in train­ing; pi­lots lend scale to the air­craft, which is ca­pa­ble of land and wa­ter op­er­a­tions thanks to its Wi­paire am­phibi­ous floats

Wa­ter scoop­ing tech­nique is to touch down at around 65 knots, open the scoops at 55 to 60 and feed in power to main­tain speed as the 800 gal­lon tank fills

Most wa­ter re­leases are im­me­di­ate, mean­ing the stick has to go hard for­ward to avoid an ex­treme nose-up at­ti­tude af­ter re­lease (note full-down el­e­va­tor)

A fif­teen min­utes max­i­mum ‘scram­ble time’ is ex­pected

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