Posts about: "RUN/CUTOFF" [Posts: 186 Pages: 10]

In the case of (2) or (3), would the expected response be "Why did you cutoff"?

I would have thought a pilot would notice the engines spooling down, and comment on that. To immediately jump to the cutoff switches as the cause rather implies something drew attention to the switches.

Then there is a 10+ second gap before the switches are set to run again. I can't think of any good reason why the PNF would have taken so long to correct an accidental or deliberate manipulation of the switches.

The fact that one of the pilots verbally asked why they were off, presumably from visually observing this (?), would seem to rule out a short?

Seconds count: That was with 10 seconds delay vs. 13 seconds for engine 2.

Time was spent with the verbal exchange, and then perhaps each pilot expected the other to put the switch back?

Anyway, the preliminary report also establishes that the aircraft had only 3-4 seconds of powered flight. (Would the gear lever be operated that early?) Everyone who saw that from the CCTV video, pat yourselves on the back.

Mayday call, dual engine failure, RAT deployment all confirmed.
TCMA was a red herring, the aircraft was firmly in air mode as the accident unfolded, and the thrust levers were at takeoff thrust the whole time.

Surely when the switches turn off there would be an EICAS warning (I didn't see any mention in the report of what messages were being displayed) to the effect that switches were in CUTOFF which might have prompted the query.

Yet seconds later the transition from CUTOFF to RUN was recorded and was effective for both switches. "Effective" means all poles made contact, the spar fuel valves and EECs. Independently, on each side. We know this because both engines re-lit at different times.

Doesn't sound like spilled coffee or "a short."

The report states that "the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec" . It doesn't say at the start of the paragraph but if following from the previous paragraph then this information is sensed from the data recorder.

Again, from the report "As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN.". Again this is sensed from the data recorder.

I would be interested to know whether sounds consistent with the actual fuel control switch being moved have been picked up on the voice recorder.

Sounds like you have never spilled coffee on something with thousands of switches.
It happens, you cycle(ie.fiddle) with them until you make contact again.
We don\x92t know how the switches moved, we only know when they made contact.

Thank you! We are getting deep into fantasy land when people who've never touched one of these switches in their lives are convincing themselves of the nearly impossible probability that someone on the flight deck did not physically move the switches from RUN to CUTOFF one at a time. Who and why are the real questions.

You are absolutely correct insofar that is the most likely explanation, but see answer above. While I have found, as I suspect most, the deliberation angle most likely, since day one, it isn\x92t really fit for discussion, so the other, admittedly slightly more unlikely avenues are more appropriate and more interesting imho.



But you also underestimate my history with spilling coffee on large amounts of switches, but while tangentially relevant, that is for another thread in another forum.o-)

Intermittent faults with spillage and switches fixed by cycling/fiddling is a thing, and it is not contrary to the facts from the report. It is possible. It is also, admittedly not the most likely.

Exactly, the report said transitioned, not moved. The report just says the recording shows change of status, it does not imply deliberate action to change it.

Timeline of known events with source attribution from the preliminary report:

08:07:33 ATC: Takeoff clearance
08:07:37 A-SMGCS: Aircraft starts rolling
08:08:33 EAFR: V1 153kts
08:08:35 EAFR: Vr 155kts
08:08:39 EAFR: Gnd-Air mode transition
08:08:42 EAFR: Max IAS 180kts, Eng 1/2 Cutoff switches activate within 1 second of each other
08:08:42 CVR: "Why did you cut off", "I did not" (exact time not specified)
08:08:42 A-SMGCS: RAT deployed (exact time not specified)
08:08:47 EAFR: Both engine N2 below min idle. RAT hyd pwr commences
08:08:52 EAFR: Eng 1 cutoff to RUN
08:08:54 EAFR: APU inlet door opens (auto start logic)
08:08:56 EAFR: Eng 2 cutoff to RUN
08:09:05 ATC: Mayday call
08:09:11 EAFR recording stops

Fuel cutoff switches operated within 1 second of each other suggests to me that the locking mechanism wasn't working as per (SAIB) No. NM-18-33. Any loose item could have accidentally (or not) operated the switches (including hands).

If I recall correctly, the Mayday call was wording to the effect "thrust not achieved". That sounds like a phrase which could be expected from a pilot who had just frantically tried to restart an engine, and realized that it was not a success, and there would not be an opportunity for another attempt. The pilot aviated, (forget navigation), then communicated - over a period of 13 seconds.

Can someone with the engineering knowledge build a timeline/timeframe for fuel cutoff switch RUN to CUTOFF -> fuel stops -> engine flameout -> N2 drops to ? -> VFSGs quit -> RAT deployment starts -> RAT full power -> APU deployment start?
Does the RAT really start providing power in 4 seconds from the E2 fuel cutoff switch RUN -> CUTOFF?


Timeline from AAIB and the public CCTV video:

08:08:33 v1 153 kts
.
08:08:35 vr 155 kts
.
.
.
08:08:39 Liftoff, A/G Air Mode, rotation at 00:18 in public CCTV video
.
.
08:08:42 E1 Fuel Cutoff Switch RUN -> CUTOFF, 180 kts
08:08:43 E2 Fuel Cutoff Switch RUN -> CUTOFF
.............? N1 N2 begin to decrease
.............? "Why did you cutoff", "I didn't"
.............? Airport CCTV shows RAT
.............? N2 < idle speed
08:08:47 RAT hydraulic power
.
08:08:49 Public CCTV video: visible loss of thrust, Alt < 200ft using wingspan
.
.
08:08:52 E1 Fuel Cutoff Switch CUTOFF -> RUN, CCTV video: visible descent
.
08:08:54 APU inlet door begins opening
.
08:08:56 E2 Fuel Cutoff Switch CUTOFF -> RUN
08:09:05 MAYDAY
08:09:11 EAFR Recording stops
08:14:44 Crash Fire Tender leaves airport

Nothing in the report suggests that the engines began to run down before the fuel was selected to cutoff. The report states a sequence of events for power loss which begins with the switches being moved to cutoff. The maximum airspeed was immediately before the switches were moved, so there had not been a power rundown prior to that:

This is a preliminary report. It is quite detailed for a preliminary report.

Examining the before-takeoff checklists seems like it would be akin to examining the re-arrangement of the deckchairs before the titanic even hit the iceberg.

The engines were switched off. Unlike Embraer, B & A have no protections stopping you switching an engine off inadvertently. From everything in the report, everything operated exactly as designed. I am not certain of how long the relight window is without windmilling speed, but +- 10 seconds seems entirely reasonable.

The outstanding question that presumably requires much more in-depth investigation of the wreckage items and CVR audio is whether:

• the cutoff switches were operated deliberately (and by who)
• the cutoff switches were operated inadvertently (and by who)
• the cutoff switches were bumped (by what) and the guards failed or weren't installed
• some electrical failure perfectly mimicked both many-pole switches being operated, then being operated again (seems unlikely)

Y'all are killing me.
If the intent is malicious, then if you know how the system works then you know how to try and confuse the investigation afterwards so that your family doesn't have to deal with you being the devil who did this. Read the entire of MH 370 if you doubt me.
Yeah.

I had the "opportunity" to investigate more than one fatal crash/mishap, and we dove down into the rat-hole of knobology and switch-ology. I read with some care the posts of one of our more sensible members, PJ2, as regards switches.

I'll leave the CVR extracts to those who want to run down that rat-hole, but WHO was flying and WHO was (doing all else) begins to matter.
Do any of you actually know who was PF and who was PM?
If you know that, how do you know that?

!!!! me, this thread is already going off the rails.

I haven\x92t seen this question asked and answered so apologies if I\x92ve missed it.

What observation(s) would or could have alerted either pilot to the fact that the fuel cutoff switches had been set to CUTOFF?

There is an EICAS message that comes up when an engine is shutdown (there is a small delay), which might prompt them to look at the switch - or just the sound the switch makes could prompt a quick glance down at the switch.

Both of the comments above imply that the 10 second wait to set the switches back to RUN is excessive and inexplicable for an "experienced" pilot.

Having read both previous threads, I recall there were easily a dozen or two comments that claimed that a pilot's hands should be nowhere near the thrust levers or fuel switches until 400' AGL, no matter if an engine is out or on fire. (This was in response to suspicions that one of the pilots has prematurely actioned the engine-out memory items.) A similar number of comments emphasized that the pilots should calmly verify any engine-related issues before taking any action that might affect thrust, and that their training emphasizes this.

You can't have it both ways. Either pilots are expected to react instantly (and cause mistakes like shutting off both engines by misreading the situation) or they're expected to take a moment to assess an unexpected failure before acting (in which case 10 seconds is still pretty darn fast).

I lean toward the latter of those.

Ever since the two 767 events in the mid 1980's where a pilot - thinking he was activating the supervisory Electronic Engine Control switches - set both engine fuel switches to CUTOFF (fortunately at ~3,000 ft. so the engines had time to relight and recover), the FAA has mandated something called a "Quick Windmill Relight" capability. Basically - with the engine at high power - the fuel switch is set to CUTOFF, then (IIRC) ten seconds later set back to RUN. The engine must recover and produce thrust within (again, IIRC) 90 seconds. It's a very challenging test for the FADEC s/w.
I assume the 10 second pause is based on how long it took the two 767 event pilots to realize their error and return the switches to RUN.