737 Probe Heat ON before start-up
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737 Probe Heat ON before start-up
Usually, the Probe Heat (or Pitot Heat for the Classic) switches are selected to ON after engine start-up. Supplementary Procedures 16 for Cold Weather Operations clearly state to put them on after the preflight procedure. Some argue that switching them on with say just 7° C and wet runway or light rain would be overkill, but these are icing conditions also according to the FCOM. Would this be too pedantic?
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If that's what's specified in your FCOM it's probably best just to do it. You can't just pick and choose the bits you like.
Our FCOM makes a distinction between icing conditions and freezing conditions with the latter being 3 degrees or below and any form of visible moisture. We only perform the SP you refer to in freezing conditions.
Our FCOM makes a distinction between icing conditions and freezing conditions with the latter being 3 degrees or below and any form of visible moisture. We only perform the SP you refer to in freezing conditions.
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Our FCOM has the same definition of freezing condition but it does not state when to place the switches to on. I'll ask an instructor in the company this week.
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First of all, FCOM SP 16 has very clear definition if icing/freezing conditions. Wet runway alone does not qualify, regardless of temperature.
Second, do what the FCOM says. If it's fine for pitot/static ports to be heated on the ground at OAT 50C during taxi, they'll probably survive couple of minutes on the stand at low temperatures.
Second, do what the FCOM says. If it's fine for pitot/static ports to be heated on the ground at OAT 50C during taxi, they'll probably survive couple of minutes on the stand at low temperatures.
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Guys, I think you're missing the point. The procedures don't state what conditions to turn them on, not questioning if he/she should turn them on.
I would say freezing conditions would make more sense.
I would say freezing conditions would make more sense.
On most Boeing aircraft other than the 737, probe heat is automatic - it comes on when you start the first engine or if air/ground says you're in-air. The probes can handle the heat although if someone forgot to remove the probe covers it could get interesting (and I suspect the 737 uses the same probes). The exception is the inlet probes on some EPR engines (747-400, 757, 767) - if you put the aircraft in air mode while on the ground (e.g. maintenance activities) you need to pull the engine probe heat breakers first of you can overheat the engine probes and damage them (and they are pricey). Used to be a common flight line problem on the 747-400 - hence new engine probe heat logic was used on the 777 and 787 EPR engines.
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The last sentence in the above quote is probably the most sensible part of this thread... it doesn’t matter what X, Y or Z airline does, just do what it says in your airline’s manuals, and if you’re not certain ask your company trainers or chief pilot. Don’t start making stuff up because you did it at the last company or your mate does it at his or you read it on an Internet forum.
and if you’re not certain ask your company trainers or chief pilot.
Contact the manufacturer and ask for clarification if you feel that the FCOM is not clear enough.
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Not at my operator. You're there because you chose to be there. If a trainer or examiner tells me what I need to do, I will do it. If it is wrong then I can put his/her name to it.
You are very naïve if you think that just because one is chief pilot or high up in the food chain as a company trainer they are necessarily accurate in their opinions. They are there because of seniority; not always because they are the experts.
Contact the manufacturer and ask for clarification if you feel that the FCOM is not clear enough.
Contact the manufacturer and ask for clarification if you feel that the FCOM is not clear enough.
Centaurus, is correct in his statement, and his final sentence tells you what to do about it, with that advice you can present to your management, that done your job is done, management then can't say they didn't know if an incident occurs.
The QF 747 overrun at Bangkok in part occurred due to procedures introduced, flap 25°, idle reverse being normal ops. Some pilots had never seen a flap 30° landing. Boeing advice,
https://www.atsb.gov.au/publications...904538_001.pdf
Then there was the widely accepted upset training that, following the AA587 fatal, that came under scrutiny and found a lack of understanding in the industry about maneuvering speed.
https://www.ntsb.gov/investigations/...ts/AAR0404.pdf
You have to question even decisions made by a regulator, ours tells us GA aircraft are not permitted to fly if the temp exceeds 40°C, reflecting an ignorance about DA, and despite the manufacturers saying otherwise.
The QF 747 overrun at Bangkok in part occurred due to procedures introduced, flap 25°, idle reverse being normal ops. Some pilots had never seen a flap 30° landing. Boeing advice,
Regarding the 747-400, Boeing recommends Flaps 30 be used to minimise landing distance and landing speed. Flaps 25 will provide better noise abatement and reduce flap wear. Therefore, flaps 25 is an acceptable flaps setting as long as the crew is satisfied that there is ample runway available for the given conditions.
Boeing does not consider the standard practice of going to reverse idle (idle detent) only to be patently unsafe, but does think that it reduces the existing performance margins. It is acceptable pilot technique to do this (using good judgement) as an exception to the normal procedures when landing on a long, dry runway. We perceive, however, that there is a human factors issue of developing a habit pattern of not using reverse thrust beyond the idle detent. The pilot may then fail to respond quickly when such reverse thrust is needed during an RTO [rejected takeoff] or landing in some type of performance-critical situation. We therefore do not provide a “No Technical Objection” for this as the standard operating policy. (Bolding mine)
If the reverse idle technique is adopted, it should be taught as the exception rather than the rule. Further, we would encourage simulator drills to be incorporated into the transition and recurrent training courses that would require pilots to use judgement to use full reverse thrust as the best successful means of stopping the airplane. This would periodically reinforce this concept of using that capability when needed.
Observations:
At the time of the accident, the flaps 25/idle reverse landing procedure had, by and large, become ‘the company norm’. For a significant proportion of company B747-400 pilots, the flaps 25 configuration was more difficult to fly than the flaps 30 configuration with respect to speed control and runway aim point.
Although the company procedures for flaps 25 and idle reverse did note that alternative configurations should be used for ‘contaminated runways’ and ‘abnormal conditions’, these special conditions were not adequately defined. In addition, company training did not ensure that crews knew when other configurations (i.e. flaps 30 and/or full reverse thrust) should be used. Training in recent years had emphasised the capability of the aircraft’s braking system, but had neither emphasised adequately the situations in which braking effectiveness could be reduced nor the importance of using maximum reverse thrust on water-affected runways. The company’s pre-1996 policy of using flaps 30 and maximum reverse thrust as standard practice provided inherent defences for contaminated runway operations. The introduction of the flaps 25/idle reverse procedures enhanced the potential for the reduced level of knowledge of contaminated runway issues within the company to become problematic. Although Qantas provided procedures and training regarding many aspects of operations in adverse weather, it did not have in place appropriately documented information and procedures for B747-400 crews regarding operations on to water-affected runways. Training in this area was minimal and did not adequately equip crews for such operations. These deficiencies culminated in the crew of Qantas One not possessing the appropriate level of knowledge to properly evaluate the effects that weather at the aerodrome might have on landing performance.
Responses to the pilot survey, along with information obtained during interviews, indicated that the Qantas One flight crew were not atypical of most other company B747-400 pilots. There was, therefore, an unquestionable link between the performance of the crew and the company flight operations system in which they trained and operated.
Boeing does not consider the standard practice of going to reverse idle (idle detent) only to be patently unsafe, but does think that it reduces the existing performance margins. It is acceptable pilot technique to do this (using good judgement) as an exception to the normal procedures when landing on a long, dry runway. We perceive, however, that there is a human factors issue of developing a habit pattern of not using reverse thrust beyond the idle detent. The pilot may then fail to respond quickly when such reverse thrust is needed during an RTO [rejected takeoff] or landing in some type of performance-critical situation. We therefore do not provide a “No Technical Objection” for this as the standard operating policy. (Bolding mine)
If the reverse idle technique is adopted, it should be taught as the exception rather than the rule. Further, we would encourage simulator drills to be incorporated into the transition and recurrent training courses that would require pilots to use judgement to use full reverse thrust as the best successful means of stopping the airplane. This would periodically reinforce this concept of using that capability when needed.
Observations:
At the time of the accident, the flaps 25/idle reverse landing procedure had, by and large, become ‘the company norm’. For a significant proportion of company B747-400 pilots, the flaps 25 configuration was more difficult to fly than the flaps 30 configuration with respect to speed control and runway aim point.
Although the company procedures for flaps 25 and idle reverse did note that alternative configurations should be used for ‘contaminated runways’ and ‘abnormal conditions’, these special conditions were not adequately defined. In addition, company training did not ensure that crews knew when other configurations (i.e. flaps 30 and/or full reverse thrust) should be used. Training in recent years had emphasised the capability of the aircraft’s braking system, but had neither emphasised adequately the situations in which braking effectiveness could be reduced nor the importance of using maximum reverse thrust on water-affected runways. The company’s pre-1996 policy of using flaps 30 and maximum reverse thrust as standard practice provided inherent defences for contaminated runway operations. The introduction of the flaps 25/idle reverse procedures enhanced the potential for the reduced level of knowledge of contaminated runway issues within the company to become problematic. Although Qantas provided procedures and training regarding many aspects of operations in adverse weather, it did not have in place appropriately documented information and procedures for B747-400 crews regarding operations on to water-affected runways. Training in this area was minimal and did not adequately equip crews for such operations. These deficiencies culminated in the crew of Qantas One not possessing the appropriate level of knowledge to properly evaluate the effects that weather at the aerodrome might have on landing performance.
Responses to the pilot survey, along with information obtained during interviews, indicated that the Qantas One flight crew were not atypical of most other company B747-400 pilots. There was, therefore, an unquestionable link between the performance of the crew and the company flight operations system in which they trained and operated.
Then there was the widely accepted upset training that, following the AA587 fatal, that came under scrutiny and found a lack of understanding in the industry about maneuvering speed.
https://www.ntsb.gov/investigations/...ts/AAR0404.pdf
You have to question even decisions made by a regulator, ours tells us GA aircraft are not permitted to fly if the temp exceeds 40°C, reflecting an ignorance about DA, and despite the manufacturers saying otherwise.
Megan: You are correct in what you say about the QF BKK over-run but by far the more important factors were - the overriding by the captain of the F/O's overshooting actions then the incomplete control handover during the landing roll. In other words it was an almost complete breakdown of SOPs and accepted actions!
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If a trainer or examiner tells me what I need to do, I will do it. If it is wrong then I can put his/her name to it
So it’s ok if you’re not happy with company SOPs to just change them and do something different because you think your chief pilot or company training department is wrong
Meikleour, so right you are.
The point I was attempting to make is that everyone is fallible, the chief pilot, regulator, manufacturer etc etc and it is up to you to educate yourself if you believe something is amiss, and present it to those in authority. Of course it may be very well be that it is you who have the bull by the horns, but you'll be put on the straight and narrow and receive an education by raising your concerns.
I wonder if the OP is confusing ‘Icing’ conditions with ‘Freezing’ conditions? I am currently mid-way through line training on the 737NG (having come from regional jets and turbo-props.) Our fleet is a mix of ‘mid-life’ (up to 20 year old, and new aircraft.)
Probe heats aren’t automatic on ours.
We have supplementary procedures for freezing (temp 3•C or less, wet runway and / or visible moisture) as distinct from ‘icing conditions’ mentioned by the OP. We performed them yesterday. Freezing conditions supplementary procedures include turning the probe heats on before start, and performing a 70% N1 runup for 30 seconds on the seconds on the runway before brakes release and TOGA being pressed.
But clearly, I appreciate different operators have varied definitions and procedures, so obviously, go with what’s in your manuals (or ask a Trainer to clarify.)
Probe heats aren’t automatic on ours.
We have supplementary procedures for freezing (temp 3•C or less, wet runway and / or visible moisture) as distinct from ‘icing conditions’ mentioned by the OP. We performed them yesterday. Freezing conditions supplementary procedures include turning the probe heats on before start, and performing a 70% N1 runup for 30 seconds on the seconds on the runway before brakes release and TOGA being pressed.
But clearly, I appreciate different operators have varied definitions and procedures, so obviously, go with what’s in your manuals (or ask a Trainer to clarify.)
Last edited by Jump Complete; 28th Feb 2020 at 10:07.
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I wonder if the OP is confusing ‘Icing’ conditions with ‘Freezing’ conditions? I am currently mid-way through line training on the 737NG (having come from regional jets and turbo-props.) Our fleet is a mix of ‘mid-life’ (up to 20 year old, and new aircraft.)
Probe heats aren’t automatic on ours.
We have supplementary procedures for freezing (temp 3•C or less, wet runway and / or visible moisture) as distinct from ‘icing conditions’ mentioned by the OP. We performed them yesterday. Freezing conditions supplementary procedures include turning the probe heats on before start, and performing a 70% N1 runup for 30 seconds on the seconds on the runway before brakes release and TOGA being pressed.
But clearly, I appreciate different operators have varied definitions and procedures, so obviously, go with what’s in your manuals (or ask a Trainer to clarify.)
Probe heats aren’t automatic on ours.
We have supplementary procedures for freezing (temp 3•C or less, wet runway and / or visible moisture) as distinct from ‘icing conditions’ mentioned by the OP. We performed them yesterday. Freezing conditions supplementary procedures include turning the probe heats on before start, and performing a 70% N1 runup for 30 seconds on the seconds on the runway before brakes release and TOGA being pressed.
But clearly, I appreciate different operators have varied definitions and procedures, so obviously, go with what’s in your manuals (or ask a Trainer to clarify.)
Last edited by Banana Joe; 28th Feb 2020 at 13:48.
I am no expert, although am type rated on the 737 - 300/400: Our teaching was that the Pitot heaters are selected to on as part of the after engine-start flow. No reference to outside conditions:
~Set Flaps.
~Genny 2 then 1 on line.
~PITOT heaters on.
~Eng Ant-ice on if reqd.
~Packs On.
~APU bleed off.
~Pressurisation to FLT.
~Engs to CONT.
~RECALL checked.
Read checklist, call for taxi.
~Set Flaps.
~Genny 2 then 1 on line.
~PITOT heaters on.
~Eng Ant-ice on if reqd.
~Packs On.
~APU bleed off.
~Pressurisation to FLT.
~Engs to CONT.
~RECALL checked.
Read checklist, call for taxi.
Banana Joe, my apologies if that across badly about your comprehension of icing / freezing conditions.
Your manuals may be different (unless we fly for same company!) but just for comparison (because yours might be saying the same thing in a different way - I’m no stranger to confusing or contradictory manuals.)
I have my EFB on my lap, open at Flying Manual Part B - Supplementary Procedures, Adverse Weather, Cold Weather Operations.
Here is it exactly.
————
Preflight Procedure - First Officer
Do the following step after completing the normal Preflight Procedure - First Officer.
PROBE HEAT switches ...... ON
Verify that all probe heat lights are extinguished.
Your manuals may be different (unless we fly for same company!) but just for comparison (because yours might be saying the same thing in a different way - I’m no stranger to confusing or contradictory manuals.)
I have my EFB on my lap, open at Flying Manual Part B - Supplementary Procedures, Adverse Weather, Cold Weather Operations.
Here is it exactly.
————
Preflight Procedure - First Officer
Do the following step after completing the normal Preflight Procedure - First Officer.
PROBE HEAT switches ...... ON
Verify that all probe heat lights are extinguished.