Hi BOAC, I will have a go.
The AMM (31-53-00) states “The takeoff warning function gives an aural warning sound if the airplane is in an unsafe condition during takeoff or if the ground spoiler interlock valve remains open after takeoff.”
To clarify this, excluding cabin altitude warnings, the intermittent horn (I wont call it the T/O config warning horn because it isn’t always that) will only sound on the ground if the thrust levers are more than 53 degrees AND
• Speedbrake lever is not down
• Parking brake is set
• Ground spoilers have pressure
• LE flaps and slats are not extended, or have an uncommanded motion
• TE flaps are not in a takeoff position, or are in a skew or asymmetry condition, or have an uncommanded motion
• Stabilizer is out of the green band.
Or in the air when the landing gear takeoff warning cutoff circuit breaker is closed, the aural warning system gives a takeoff warning sound if both of these conditions occur:
• LE flaps and slats are not extended
• Ground spoiler interlock valve is open.
To answer your questions specifically:
A1: Yes, as soon as the LED’s have retracted.
A2: I don’t know, but I don’t think so.
A3: Correct, it will sound until the first flap selection. Maybe keep flaps at 1 or more if you get this problem to help you think?
A4: Now sure exactly what you mean, but when airtesting we switch the SPOILER A & B switches off to ensure that no panels deploy when not locked down. This is done by the CAA schedule at FL350 / M0.74 / Clean and by the Boeing schedule at <FL200 / 130kts / Flap 40. Both configs are designed to generate a large pressure differential on the wing which would show any tendency to lift a panel. The reason for this test is because of an incident to the
DC9 which was nearly lost when the crew selected full flap on final and the aircraft rolled because a spoiler panel became unlocked and deployed.
A5: Not sure, the finer points of the PSEU are lost on me; but the PSEU certainly commands the aural warning module to sound the intermittent horn.
A6: NO!!! this has a potentially big effect, see A4. That said, I have done approx 200 spoiler float checks on 737’s with no roll control problem or roll observed.
S&L