If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user
Holdover Time (HOT) Tables
From SKYbrary Wiki
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 The effect of such out of date information being still accessible has resulted in many Operations Manuals being out of date on this critical safety subject.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:
- "Recommendations for De-Icing/Anti-Icing Aeroplanes on the Ground" (Edition 28 of this guide was published in July 2013) and
- "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)
- 2013/2014 Transport Canada HOT tables
- Transport Canada: Guidelines for Aircraft Ground Icing Operations amendments to which can be found with the latest edition of the HOT tables issued prior to each winter season.
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:
Accidents and Incidents resulting from airframe icing and problems with anti-icing fluids:
- A306, Paris CDG France, 1997 (GND LOC HF) (On 30 July 1997, an Airbus A300-600 being operated by Emirates Airline was departing on a scheduled passenger flight from Paris Charles de Gaulle in daylight when, as the aircraft was accelerating at 40 kts during the take off roll, it pitched up and its tail touched the ground violently. The crew abandoned the takeoff and returned to the parking area. The tail of the aircraft was damaged due to the impact with the runway when the plane pitched up.)
- RJ85, Helsinki Finland 2010, (AW GND LOC) (On 12 June 2010, a requested 22R runway inspection at Helsinki in normal daylight visibility carried out after a severe engine failure during the take off roll had led an Avro RJ85 being operated by Finnish Airline Blue1 on a scheduled passenger flight to Copenhagen to reject that take off at high speed. This inspection had not detected significant debris deposited on the runway during the sudden and severe engine failure. Two passenger aircraft, one being operated by Finnair to Dubrovnik, Croatia and the other being operated by Swedish airline TUIfly Nordic to Rhodes, Greece then departed the same runway before a re-inspection disclosed the debris and it was removed. Neither of the aircraft which used the runway prior to debris removal were subsequently found to have suffered any damage but both were advised of the situation en route.)
- A319, Stockholm Arlanda Sweden, 2011 (RI HF GND) (On 5 February 2011, an Airbus A319-100 being operated by Air Berlin on a passenger flight departing Stockholm inadvertently proceeded beyond the given clearance limit for runway 19R and although it subsequently stopped before runway entry had occurred, it was by then closer to high speed departing traffic than it should have been. There was no abrupt stop and none of the 103 occupants were injured.)
- B772, Denver CO USA, 2001 (GND FIRE HF) (On 5 September 2001, a British Airways Boeing 777-236 on the ground at Denver USA, was substantially damaged, and a refuelling operative killed, when a fire broke out following the failure of a refuelling coupling under pressure because of improper attachment.)
- 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.)
- … 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, 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, Failure to De/anti Ice) for this property.