Hotel Mode for Aircraft

Never heard of Hotel Mode. Have heard of the following. Derived from the Morse Code Alphabet.

"A" Alfa, "B" Bravo, "C" Charlie, "D" Delta, "E" Echo, etc, etc.

As I understand it, Hotel mode is a mode of operation where the aircraft is on the ground, operating at a reduced power level for running certain systems only.

'Hotel Mode' allows a pilot to disengage the propeller of one turbine. This will allow the plane to sit at a gate with the engine running, providing power and air to the plane without the prop spinning.

This feature also replaces an on-board auxiliary power unit (APU), saving weight.

Like you, I have no idea where the phrase originated. I hope someone comes forward with an answer; now I am curious too.

GA

from http://www.pprune.org/archive/index.php/t-289339.html

The term hotel mode is actually a nautical term. When cruise ships would pull into port, they would disengage the screws from the powerplants so that they could still get electricity to keep the ship powered without turning the screws.

Not to be confused with the acronym typo HOTOL...

"hotel mode" for aircraft originated from the marine industry. Ships pulled into port and disengaged the prop shaft to allow the engines to be used for electricity generation for on-board services.

Similar for aircraft where there is no ground power unit, it enables the #2 engine (non-boarding side) to be used for power (aircon and services) without the prop rotating. There is a weight and space saving advantage from not having to instal an APU. An entertaining simulation;

http://wn.com/Flight1_ATR_72_Startup_Tutorial_Hotel_Mode

The ships I served aboard had a continuous shaft from the turbine's reduction gears to the "screws" (props) so there was no "disengaging" of them. Turbine generators had their own turbines to turn the generators. I'm sure the setup would be similar on other ships ... you cannot possible depend on one turbine to do everything.

I'm guessing the "hotel" term came from the services you typically expect for habitability in any public or private space: electric - water - heating/cooling, sewage --- similar to what we expect in a hotel.

Just a guess about the term .. and a fact, about US Navy equipment, of which I served in both old WWII tincans and nuclear cruisers. And in hotels too!!

"Ya learn something new everyday."

Never heard of "hotel mode", even after nearly 50 years around aircraft.

I'm very familiar with rotor brakes on helicopters but I had no idea about propeller brakes on fixed wings.

Hooker