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Holdover Time (HOT) Tables

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Category: Ground Operations Ground Operations
Content source: SKYbrary About SKYbrary
Content control: EUROCONTROL EUROCONTROL

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Description

Aircraft Ground De/Anti Icing Holdover Time (HOT) tables are approved by the SAE G-12 Committee are issued each year prior to the northern winter season.

These are then reviewed by AEA, FAA, and TC (Transport Canada) who are the main practical sources of HOT information and each issues their own version of the HOT Tables and associated support publications independently of each other and SAE. The generic changes from one season to the next are usually relatively few. However, in recent years, issues with residues from thickened fluids have been the main driver for the appearance of product-specific HOT tables, which are increasingly used by operators.

Other "official" sources sometimes publish HOT which are then left as "current" when they cease to be the latest versions. The effect of such out of date information being still accessible has resulted in many Operations Manuals being out of date on this critical safety subject.

In recent years, several companies have been developing systems that measure precipitation rate in real-time. These systems, referred to as liquid water equivalent systems (LWES), can be used by check-time determination systems (CTDS) and holdover time determination systems (HOTDS) to calculate more precise holdover times than can be obtained from the HOT Tables. They do this by using the weather data they collect as the input to the underlying assumptions employed in calculating the times in the HOT Tables.

Association of European Airlines (AEA)

  • The two regularly updated AEA Guides on the subject are:
    1. "Recommendations for De-Icing/Anti-Icing Aeroplanes on the Ground" (Edition 28 of this guide was published in July 2013) and
    2. "Recommendations and Background Information for De-Icing/Anti-Icing Aeroplanes on the Ground" (Edition 10 of this guide was published in August 2013)

Transport Canada (TC)

Federal Aviation Administration (FAA)

As a result of the development of LWES, CTDS and HOTDS, the FAA is making the regression coefficients and equations underlying the holdover time tables available to users:

Related Articles

Accident Reports

Accidents and Incidents resulting from airframe icing and problems with anti-icing fluids:

  • Vehicle/B752 Dublin Ireland, 2009 (RI GND) (On 29 May 2009, a Boeing 757-200 being operated by UK Airline Thomson Airways on a passenger charter flight from Sharm-el-Sheikh, Egypt to Dublin and having just landed on runway 10 at destination at night in poor visibility overtook a small ride-on grass mower moving along the right hand side of the runway in approximate line with the aircraft’s right hand wing tip. The driver of the mower was unaware of the arriving aircraft until he heard it on the runway behind him. Prior to the landing, ATC had been informed that all grass-cutting equipment previously working on and around the runway had cleared it.)
  • B190, vicinity Charlotte NC USA, 2003 (AW GND LOC HF) (On 8 January 2003, a B190, operated by Air Midwest, crashed shortly after take off from Charlotte, NC, USA, following loss of pitch control during takeoff. The accident was attributed to incorrect rigging of the elevator control system compounded by the airplane being outside load and balance limitations.)
  • E135, Norwich UK, 2003 (RE WX HF GND) (On 30 January 2003, an Embraer 135 being operated by Swedish company City Airline on a scheduled night passenger flight from Aberdeen to Norwich overran the slush-covered landing runway following a late touchdown in normal visibility. There were no injuries to any of the 25 occupants and with no signs of fire, the passengers subsequently disembarked via the aircraft integral airstairs. There was only minor damage to the aircraft landing gear which required wheel replacement.)
  • A332, Sydney Australia 2009, (GND LOC HF) (On 4 July 2009, an Airbus A332 being operated by Jetstar Airways on a scheduled passenger flight from Sydney to Melbourne carried a 750 kg ULD which had been expressly rejected by the aircraft commander during the loading operation without flight crew awareness. There was no reported effect on aircraft handling during the flight.)
  • ATP, Jersey Channel Islands, 1998 (GND HF) (On 9 May 1998, a British Regional Airlines ATP was being pushed back for departure at Jersey in daylight whilst the engines were being started when an excessive engine power setting applied by the flight crew led to the failure of the towbar connection and then to one of the aircraft's carbon fibre propellers striking the tug. A non standard emergency evacuation followed. All aircraft occupants and ground crew were unnjured.)
  • … further results

warning.png"Ground de/anti icing" is not in the list of possible values (Taxiway collision, On gate collision, Aircraft / Aircraft conflict, Aircraft / Person conflict, Aircraft / Vehicle conflict, Aircraft / Object or Structure conflict, ATC clearance error, Ground de/anti icing ineffective, Ground de/anti icing not available, Failure to De/anti Ice, Jet Blast / Prop wash, Surface Friction, Towed aircraft involved, Aircraft Push Back, Incorrect Parking Position, Airbridge Positioning, Both objects moving, Wingtip clearance, Centreline obscured, Accepted ATC clearance not followed, Surface Lighting control, Hold Loading, Passenger Loading, Cargo Loading, Fuel Loading, Dangerous Goods, Engine Ground Running, Engine Powered Systems Test, No Flight Crew on Board, Charting Error) for this property.

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