US Army helicopters cleared for moderate icing: Are British mil?
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US Army helicopters cleared for moderate icing: Are British mil?
According to Defence Helicopter:
U.S. Army aviation sources say service helicopters are equipped to operate safely under icy conditions, though the degree of protection varies and can be increased where necessary.
The mainstay aircraft of the fleet - Black Hawks, Chinooks and Apaches have ant-icing systems - systems that prevent the formation of ice - from covering key aerodynamic parts of the structure. “These include main rotor blades and tail rotors, but more significantly the engine intakes - which have heated inlet ramps,’ said an official with AMCOM, the Army’s aviation and missile command in Huntsville, Ala.
‘The only ones we’re not sure about are the Kiowa Warrior scout helicopters. Some of those aircraft are ant-ice equipped and some are not.’
Most helicopters currently being operated in Afghanistan ‘belong’ to US Special Operations Command (USSOCOM), and not directly to the regular Army Materiel Command support structure. ‘Those are 160th SOAR ships, and they have a different procurement structure, so you’d have to ask them the specifics,’ the official said.
‘However. all out aircraft - all of them, including the special ops ones - have to meet an icing operational standard down to minus 25 degrees F. Whether they have additional protection or not, that’s just a given.’
The helicopters can also been equipped with extra cold-weather kits that are used to provide starting and maintenance assistance when operating under severely adverse conditions. These kits help service consumables used in the aircraft, as well as provide extra current for starting turbines and APUs.
The Army works off an icing standard provided in 1980 when the entire range of aircraft went through airborne icing tests in the Duluth, Minn area. ‘As you know we haven’t changed the fleet since then, so the data we collected is still valid,’ an official commented.
But there was no confirmation from Huntsville on one question: whether ice brought down a special operations MH-60K on or about November 2 while flying near the Afghani - Pakistan border.
During that incident the pilot apparently landed hard, damaging his aircraft. A second helicopter - not identified as a Black Hawk - then landed. ‘We doubt the icing story,’ the source said, ‘because of the presence of the other aircraft. Wouldn’t it have got iced up, too?’ Other reports however said the second aircraft picked up the downed crew from a different location - making the ice theory at least plausible.
Helicopter pilots can obviously expect extreme flying conditions when winter closes in in Afghanistan. Altitudes around Kabul are the highest - varying between 12,000 and sometimes as high as 18,000 feet. Around Herat and Kandahar, however, the terrain is lower on average - around 5,000 ft. AMCOM sources had no comment on helicopter performance at the higher altitudes. It’s obvious, however, that for all the Army fleet compromises in payload/range and manoeuvrability are inevitable, certainly when operating at the terrain elevations around Kabul.
‘We’re OK in rain, and we’re OK in moderate icing and in IFR conditions. But if you get high mountain winds, and you’re up at altitude, then we’re going to be relying a lot on out training - as we always do,’ the source said.
Sources also said that the logistics train for spares to support Army (non-SOF) helicopters in Pakistan, Uzbekistan and elsewhere was ‘working quite OK,’ and that no readiness issues arising from this quarter should be experienced if - or when - ground operations in Afghanistan begin.
[ 09 November 2001: Message edited by: Hoverman ]
[ 09 November 2001: Message edited by: Hoverman ]
U.S. Army aviation sources say service helicopters are equipped to operate safely under icy conditions, though the degree of protection varies and can be increased where necessary.
The mainstay aircraft of the fleet - Black Hawks, Chinooks and Apaches have ant-icing systems - systems that prevent the formation of ice - from covering key aerodynamic parts of the structure. “These include main rotor blades and tail rotors, but more significantly the engine intakes - which have heated inlet ramps,’ said an official with AMCOM, the Army’s aviation and missile command in Huntsville, Ala.
‘The only ones we’re not sure about are the Kiowa Warrior scout helicopters. Some of those aircraft are ant-ice equipped and some are not.’
Most helicopters currently being operated in Afghanistan ‘belong’ to US Special Operations Command (USSOCOM), and not directly to the regular Army Materiel Command support structure. ‘Those are 160th SOAR ships, and they have a different procurement structure, so you’d have to ask them the specifics,’ the official said.
‘However. all out aircraft - all of them, including the special ops ones - have to meet an icing operational standard down to minus 25 degrees F. Whether they have additional protection or not, that’s just a given.’
The helicopters can also been equipped with extra cold-weather kits that are used to provide starting and maintenance assistance when operating under severely adverse conditions. These kits help service consumables used in the aircraft, as well as provide extra current for starting turbines and APUs.
The Army works off an icing standard provided in 1980 when the entire range of aircraft went through airborne icing tests in the Duluth, Minn area. ‘As you know we haven’t changed the fleet since then, so the data we collected is still valid,’ an official commented.
But there was no confirmation from Huntsville on one question: whether ice brought down a special operations MH-60K on or about November 2 while flying near the Afghani - Pakistan border.
During that incident the pilot apparently landed hard, damaging his aircraft. A second helicopter - not identified as a Black Hawk - then landed. ‘We doubt the icing story,’ the source said, ‘because of the presence of the other aircraft. Wouldn’t it have got iced up, too?’ Other reports however said the second aircraft picked up the downed crew from a different location - making the ice theory at least plausible.
Helicopter pilots can obviously expect extreme flying conditions when winter closes in in Afghanistan. Altitudes around Kabul are the highest - varying between 12,000 and sometimes as high as 18,000 feet. Around Herat and Kandahar, however, the terrain is lower on average - around 5,000 ft. AMCOM sources had no comment on helicopter performance at the higher altitudes. It’s obvious, however, that for all the Army fleet compromises in payload/range and manoeuvrability are inevitable, certainly when operating at the terrain elevations around Kabul.
‘We’re OK in rain, and we’re OK in moderate icing and in IFR conditions. But if you get high mountain winds, and you’re up at altitude, then we’re going to be relying a lot on out training - as we always do,’ the source said.
Sources also said that the logistics train for spares to support Army (non-SOF) helicopters in Pakistan, Uzbekistan and elsewhere was ‘working quite OK,’ and that no readiness issues arising from this quarter should be experienced if - or when - ground operations in Afghanistan begin.
[ 09 November 2001: Message edited by: Hoverman ]
[ 09 November 2001: Message edited by: Hoverman ]
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A few points for my benefit more than anyone else. Please disagree as required 
"U.S. Army aviation sources say service helicopters are equipped to operate safely under icy conditions, though the degree of protection varies and can be increased where necessary"
Rigid
o they mean engine icing or airframe icing conditions? For the latter, a general rule is a temp of <= 0degC with a visibilty of less than 1000 m due to the presence of water.
"The mainstay aircraft of the fleet - Black Hawks, Chinooks and Apaches have ant-icing systems - systems that prevent the formation of ice - from covering key aerodynamic parts of the structure. “These include main rotor blades and tail rotors, but more significantly the engine intakes - which have heated inlet ramps,’ said an official with AMCOM, the Army’s aviation and missile command in Huntsville, Ala."
Rigid:So do the USA operate AH or Chinook with heated blades? I dont think so, but would love to hear otherwise. And I dont mean"did they do a trial" but do they rountinely fly in icing conditions.
‘However. all out aircraft - all of them, including the special ops ones - have to meet an icing operational standard down to minus 25 degrees F. Whether they have additional protection or not, that’s just a given.’
rigid: What is not clear from this statement is whether we are talking about ops at temps of -25degF in visibility of less than 1000m or not, ie in cloud or VFR.
"The Army works off an icing standard provided in 1980 when the entire range of aircraft went through airborne icing tests in the Duluth, Minn area. ‘As you know we haven’t changed the fleet since then, so the data we collected is still valid,’ an official commented. "
Rigid: So sure, the data they gathered is still valid, but what does it show!! Very clever use of words.
Rigid: Icing severity is a function of temperature and liquid water content in the atmosphere and you can only seriously consider qualifying an ac against both simultaneous criteria. You may also wish to consider water droplet size but this would be difficult to measure and quantify to an aviator in-flt. Unles you are happy with the accrue/shed cycle and Tq rise during accrue, you are unlikely to be able to operate a cold bladed ac for sustained periods in icing conditions below a particular temp until you get very cold where ice will not accrue. You want to fly in icing conditions, get engine and blade de/anti-ice.
Ok, thats off my chest. Have a good weekend
"U.S. Army aviation sources say service helicopters are equipped to operate safely under icy conditions, though the degree of protection varies and can be increased where necessary"
Rigid
o they mean engine icing or airframe icing conditions? For the latter, a general rule is a temp of <= 0degC with a visibilty of less than 1000 m due to the presence of water. "The mainstay aircraft of the fleet - Black Hawks, Chinooks and Apaches have ant-icing systems - systems that prevent the formation of ice - from covering key aerodynamic parts of the structure. “These include main rotor blades and tail rotors, but more significantly the engine intakes - which have heated inlet ramps,’ said an official with AMCOM, the Army’s aviation and missile command in Huntsville, Ala."
Rigid:So do the USA operate AH or Chinook with heated blades? I dont think so, but would love to hear otherwise. And I dont mean"did they do a trial" but do they rountinely fly in icing conditions.
‘However. all out aircraft - all of them, including the special ops ones - have to meet an icing operational standard down to minus 25 degrees F. Whether they have additional protection or not, that’s just a given.’
rigid: What is not clear from this statement is whether we are talking about ops at temps of -25degF in visibility of less than 1000m or not, ie in cloud or VFR.
"The Army works off an icing standard provided in 1980 when the entire range of aircraft went through airborne icing tests in the Duluth, Minn area. ‘As you know we haven’t changed the fleet since then, so the data we collected is still valid,’ an official commented. "
Rigid: So sure, the data they gathered is still valid, but what does it show!! Very clever use of words.
Rigid: Icing severity is a function of temperature and liquid water content in the atmosphere and you can only seriously consider qualifying an ac against both simultaneous criteria. You may also wish to consider water droplet size but this would be difficult to measure and quantify to an aviator in-flt. Unles you are happy with the accrue/shed cycle and Tq rise during accrue, you are unlikely to be able to operate a cold bladed ac for sustained periods in icing conditions below a particular temp until you get very cold where ice will not accrue. You want to fly in icing conditions, get engine and blade de/anti-ice.
Ok, thats off my chest. Have a good weekend
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The only US Army helo with heated main blades is the Black Hawk, unless I have missed something recent. The system is a de-ice system, as it allows a thin skim of ice to build up, then rapidly heats the leading edge to disbond it and allow it to sling off with the centrifugal force. The heat is timed to toss the ice away from the tail rotor (which is also heated).
All US Army helicopters have anti-ice heated bellmouth inlets, which are continuously heated so no ice forms at all.
The Hawk is cleared into moderate ice, with a max Liquid Water Content of 1 Gm/M3. I know of no such permission for Apaches, Chinooks or the OH-58 family.
The entire Russian fleet is de-iced, for obvious reasons! So are many H-3's.
News from operators would be welcomed here.
[ 10 November 2001: Message edited by: Nick Lappos ]
All US Army helicopters have anti-ice heated bellmouth inlets, which are continuously heated so no ice forms at all.
The Hawk is cleared into moderate ice, with a max Liquid Water Content of 1 Gm/M3. I know of no such permission for Apaches, Chinooks or the OH-58 family.
The entire Russian fleet is de-iced, for obvious reasons! So are many H-3's.
News from operators would be welcomed here.
[ 10 November 2001: Message edited by: Nick Lappos ]
British Army Gazelles are not cleared for flight in any icing conditions.
The Lynx have anti ice systems (bleed air and electrically heated intakes) for the engine intakes, but nothing for the airframe or blades. Generally the Lynx is cleared to a max accumulation of 30 to 60mm of rime ice and 10 to 30mm of clear(rain) ice, depending on the mod state.
The Lynx have anti ice systems (bleed air and electrically heated intakes) for the engine intakes, but nothing for the airframe or blades. Generally the Lynx is cleared to a max accumulation of 30 to 60mm of rime ice and 10 to 30mm of clear(rain) ice, depending on the mod state.
