BUMFFPITCHH.. H?
 

Hi Guys, I was just going through the various 'aid memoirs' that we accumulate over the years, and it struck me that maybe I was doing the H for Hatches wrongly.
When taught in a PA 38 the H meant to unlock the doors (In case the Fire Service had to make an entry.) However when flying Cessnas my instructors have never querried that I did not unlock the doors on the H.
Just like to know if you unlock prior to landing in your airplane, or just check the doors are closed...?
.

I don't do anything to the doors before landing. Not that they have a lock anyway, but if they did why would I use it when in flight? Who is going to try to get in or out?
That's part of the pre take off check, not pre landing. Pre landing check is correct configuration, not everything working.... So it should be pretty straightforward and tailored to the aircraft. As in, no point checking prop pitch or undercarriage if they are fixed, but it's probably a good idea to confirm the altimeter setting and that you are using a tank with some fuel in, and on the right radio frequency. Invent your own memnonic, why don't you?
Access for rescue service? Hmmm. Not applicable at our aero club. Try not to crash.

Hatches and Harnesses - SECURE

Downwind on checkout in a Pa38. Something I've had a few times. BUT - this tme the instructor opens his door. I'd ask why, then consider a "MAYDAY - instructor breakdown" call.
​​​​​​

Hatches and Harnesses - SECURE (i.e. locked, Bloggs!)

I once learned a very good lesson from an instructor who asked what I would do if the door opened on takeoff. "Why, continue," I airily replied, having read an accident report wherein the aircraft left the runway as the unfortunate pilot tried to close an errant door and take off at the same time, "and sort it out in the air, with plenty of height in hand."

Wrong! :E

My ears are still ringing today from his opinion of what the open door might do to the tailplane structure if it came off in flight!

Secure, secure, secure. Latched and locked.

Light aircraft are thin-skinned structures of delicate, but strong, construction. If a fireman wants to get in, he'll get in, unlocked or not.

Hope that helps :ok:

I think your instructor was mindlessly repeating some silly flight school-ism. So what he is saying even if you are just about to lift off on a short field and the cabin door opens your only option is to reject and run off the end because the door might fall off and hit the tail......Really!

I challenge anybody to find a report where a light aircraft cabin door came off in flight and hurt the airplane. Like every other emergency you fly the airplane first. If the door opens early in the takeoff run you stop and get off the runway and fix the door, if it happens later in the takeoff roll without enough runway to come to a comfortable stop; you ....takeoff.

FYI in the high wing Cessna’s, if the passenger door opens, place its handle in the open position if it is not already there then just open yours about an inch. The suction will close the door without you having to reach around the passenger to tug it closed, which will take a fairly good tug. With Pipers however I have not found a way to close an open door in flight. However it is not deal flying around with the door open as it will only hang open a few inches. You will be really cold however, if it happens in winter

Nose baggage doors on twins, however are whole different story. Depending on the type you may be in big trouble with an open nose baggage door, so it is vital they are checked closed and locked on the walk around. My SOP is that the nose baggage door has only 2 states, fully open on the door stay, or closed AND locked. It will never be closed but unlocked.

PA38 - Hatches secure, Harness secure!

Well, it was a microlight helicopter, but the door opened in flight (top hinged door) and went into the rotor. Two dead. Happened about a year ago in France, and I don't think the report is out yet.

Helicopters are in a chapter of their own, anyway. Especially securitywise.
And some might say that microlights are in a chapter of their own, especially securitywise.
So microlight helicopters are not in the top drawer, from several points of view.

2 stories:
1. IMC training in a C172. Door opened as I lifted off, under the hood. Continued with takeoff, commenting to the instructor 'my door's opened'. 'Well, shut it then when safe to do so' he said. I'm DARNED sure I'd latched it locked before takeoff. I'm PRETTY sure he'd reached behind me and opened it. Door closed easily when we'd attained the cruise. Cessna doors are easy to open and close in flight Good lesson. On another flight he also had me takeoff (again under the hood) without me personally carrying out a walkraound, claiming he'd already done it and we were in a hurry. As I climbed out, the ASI started to decrease. I checked the revs and attitude, both good continued the climb and reported loss of airspeed to him. 'What are you going to do?' he asked. 'Level off after a suitable interval, declare an emergency and try to return to the field'. 'Fair enough, take off the hood and return to land'. After we landed, he showed me the 2 pieces of tape he'd put over the static vents. I must confess that I don't actually do any of this stuff with my students, but I DO talk about it so I guess the lesson gets passed on.
2. My wife was PIC in her PA28, I was pax in the right seat. Hot day and I opened the door as we backtracked the runway. I pulled it shut as we turned around at the end. Just as she lifted off, it popped open. I'd forgotten to secure the top latch. 'We've got to go back!' she exclaimed. I said we couldn't as the airfield was closing as we departed. I tried and failed to close it again so just left it trailing in the slipstream. Absolutely no effect on the handling but a bit noisy my side. The fallout was mighty, though and ten years on it's still brought up in conversation from time to time.

I've flown Cessna Aerobats with pins in the door hinges, in case you want to exit the aircraft whilst wearing a parachute. I'm sure they wouldn't do that if the thought the door was going to hit the tail. On the other hand, if you feel the need to take to a 'chute, then you might not be worrying too much about the aircraft once you've left it.

Now, as to unlatching doors before landing. This is something I DO teach in the event of a forced landing, where the fuselage might get distorted and the door would get jammed. Otherwise, they're firmly latched closed for a normal landing.

TOO

TOO
.

It is unlikely in the extreme that an opening door on a certified airplane is going to create a controllability/safety of flight concern. Airplane designers have errant opening doors in mind during the design process. That's not to encourage carelessness on the pilot's part, but rather to remind pilots that their first responsibility is to fly the plane safely, and keep flying it, until it's safely parked. Everything else is secondary. If a door has popped open, and once safely airborne, you'd like to close it, before applying silly amounts of pull on the handle, try some rudder one way or the other. The jump planes I flew with air operable doors were very easily gently opened and closed with rudder operation. If the door has an opening window (Cessna style, not the Piper hole in the window window), open the window, and pull on the lower aft portion of the window frame, it's stronger than the handle, and closing the window later is easy.

Many airplane types are permitted flight with a door removed, though often by additional approval, and sometimes with a deflector. A partial list for interest's sake includes most Beech Twins, All the Cessna singles, and a couple of twins, Most of the Piper PA series singles (though the Tomahawk does not appear on the list), and a number of other types.

If you're flying a Cessna Caravan solo, remember to lock the back cabin door from the inside (not just "closed and latched"), they can open in flight if not completely locked :uhoh:. Not harmful, just embarrassing. If you're flying a single Cessna with a baggage door, key lock it before takeoff, their latches are mediocre. The only type which I know sustains expensive damage with an errant open door in flight is the C 206/207, if a back clamshell door opens. It'll bang on the side of the fuselage and beat it up. The plane is safe to fly, but if it happens, you'd better continue on to a maintenance base, 'cause the plane is going to need repair before the next flight!

For GA singles, emergency crews are going to get in. I agree that there are flight manuals which state to unlatch doors before a forced landing - then you should certainly consider doing that, it was written for a reason. Otherwise, close them properly. Note that a few types (I'm thinking of the Cessna 177's) have a number of moving pins which latch the door closed in several places around the frame. These are moved into place in the motion of the handle from "Closed" to "Latched". If that motion of the the handle is not easy, reclose the door, as one of those pins may not have gone into position properly. If you force the handle to the "Latched" position, a pin may hang up, and spring a bit. Later in the flight, particularly in turbulence, it may pop into the correct position - it'll scare the @#!* out of you!

Forced Landing
 

From a grey and wise instructor about a checklist at some stage in the descent into the field...

F.I.E.L.D.

• Fuel - OFF
• Ignition - OFF
• Electrics - OFF (As soon as flaps are set)
• Lapstraps - Tight
• Doors - Open incase of airframe distortion

But the OP is talking about normal landings and every one of them by the sound of it.

In a forced landing your throttle also needs to be closed (in case of a duff mag) and mixture ICO. And if retractable a decision about what to do with the gear. It'll take me a while to invent a new neumonic......................

Just refer to the one published by the airplane manufactuer in the approved flight manual.

Oh, wait, none to be found there? Probably because the airplane manufacturer, and approving authorities would like you to operate to plane using the procedures and checklists provided as a part of its approved type design. I don't deny that a few mnemonics can seem handy, but I never train them, I train the airplane checklist and procedures, and expect the pilot to refer to them. If they can effectively memorize them, and apply them, okay, if they cannot, get out the checklist (which is the expectation anyway). To me, a mnemonic can become an attempted substitute for the use of a checklist in that phase in flight, and possibly result in something being missed.

I'll usually fly a dozen or so different GA types in a year, sometimes having never flown that type before, and sometimes with a modification, for which I now must include a new checklist item (later to be approved) while I fly. Two of those types will be very familiar (I own them), everything else will be something I either fly rarely, or never before. For my RG, I will always state the landing gear position, and landing surface out loud, twice, before landing (it has no warning system, which I would not rely upon anyway). Otherwise, everything else for it, and my 150, are memory items (I'm kinda used to them by now). But for nearly everything else, I'll be referring to a checklist. I would never try to think up a mnemonic and apply it as a substitute to the use of a checklist. If doing so, and misaplying it, or getting it wrong, resulted in an incident, I really could not explain why I did not use a checklist.

I did my commercial flight test on my own Cessna 150, which I'd owned for more than 15 years, at the time) 15 years ago. Suffice to say I knew that plane very well. My instructor reminded me to actually use a paper checklist during the flight test, or I'd loose marks. Yup! I found one, printed it out, used it for the flight test, and never used it again. But I sure would not have used a mnemonic during the flight test, so why would I use it any other time?

Glider canopies occasionally come loose. Rear opening canopies promptly depart the airframe. You may not notice in flight that a front opening canopy was not completely latched (don't ask).

Side opening canopies can be kept down with a bit of rudder.

Sadly glider and tow pilots have been killed when the glider pilot focuses on closing a side opening canopy instead of flying the airplane.

A towpilot was killed last year in the US when the glider got high on tow while the glider pilot was trying to close the canopy:(

The problem with mnemonic’s, in addition to the points ably made by Pilot DAR, is all the systems are not created equally.

For example take the “F” for fuel. Before take off on some airplanes the selector should be on both, on others the fullest tank and on others, a specific tank (eg main or fuselage). On some airplanes the electric boost pump must be on on others it is imperative it is off.

The only way to know these possibilities and permutations is in the aircraft manual, which is also going to have a checklist, so why on earth would not use that over some mnemonic that somebody made up.

One of the biggest problems in flight training is made up Shyte from the good idea club that mindlessly gets passed down to each new generation of instructors, just like the lunacy that you have to abort a takeoff if the door opens because it could come off and hurt the airplane

I am in the lucky position that I never was taught using them and never had to teach anyone using them either. But coming back to the original question: The school in which I instruct uses a standardised departure and emergency briefing which is kept as simple as possible and easy to remember. It includes the "unlatch doors" item for all aircraft in the fleet (Cessnas and Piper singles and twins) which makes a lot of sense to me. But only in the case of an emergency landing. In normal landings the doors remain latched of course, otherwise they would create a major distraction in case of a go-around...

I was heavily involved in flight testing and certification in the UK of the Raj Hamsa X'Air. We had a couple of incidents in testing of doors coming open in flight - it was top-hinged on a high wing aeroplane, and would fly sort of in formation with the wing, creating a rather problematic asymmetry, that could create significant control problems. If you were flying solo in the left seat and the right door came open, you'd really struggle to resolve that.

By the time it was approved in the UK, we'd made several design modifications that cured that (a secondary door catch basically). The unmodified aircraft was still approved in France and I think India, so I'd be amazed if the problem never happened in normal use there.

G

Anyone care to comment on Downwind checks ?

The Raj Hamsa XkAir is an ultra light. Because it is an ultra light it is not subject to most of the requirements of a certified aircraft. Ultra lights are also by definition very lightly built and thus have a sad significant history of inflight structural failure.

With respect to the dangers of an opened cabin door coming off in flight and damaging the aircraft I would suggest the instances of ultra light failures do little to inform with respect to that risk in certified aircraft. That being said the case for handling an open door may need to be different in Ultra light.

I personally refuse to fly in ultra light aircraft as I am not comfortable with the lack of a rigorous process to ensure design and construction safety. Since I am not familiar with UL operations please note my comments regarding the appropriate actions for a cabin door open in flight are restricted to certified light aircraft.

With respect to the force landing case I teach my students to if practicable to unlatch the door prior to touchdown, emphasizing that this must not be done at the expense of flying the aircraft.

I also tell my students that in the event of a forced landing in a retractable gear aircraft, the landing should be done gear up unless landing on a runway is assured.

Interesting points re the doors.

I once took off from a busy international airport in an early PA-34 (Seneca I). Ordinarily I'd give the doors in most a/c a thump with my fist after closing, just to check they're truly closed, but in this case the only passenger was a rated pilot...

I watched him close the door, then a little later, before powering up, asked him if he was closed and locked. Yes! he said, and gave it a half-hearted lean.

Shortly after, on the climb out, the door popped open. I don't recall now whether it was just at the top but, while it was noisy, I didn't consider it dangerous and following a quick attempt to close it (nope, it wouldn't) I elected to carry on and find a nearby small airfield to land and properly close the door - glaring at the errant passenger in the process.

What I (re) learned from that was to always check the doors with a good push myself if I could, no matter who was in the RH seat.

I was happy with the decision to carry on at the time, and would probably do so again under the same circumstances, but if anyone thinks differently it'd be good to hear from you. FWIW if it had been a quiet aerodrome I'd have just circled back and immediately sorted it out on the ground, but after weighing up the hassle factor in this case vs the likelihood of any real problem we got out of controlled airspace first...

Sure. Refer to the manufacturer's checklist. "G" for "Gear" in a mnemonic .... Not even close!!

And, if it's an RG, twice before short final, observe and state (out loud) the landing gear position, and surface you intend to land on. For example: "Wheels are down for landing on runway.", or "Wheels are retracted for ditching/intended forced landing in a plowed field.", or "Wheels are retracted, skis extended, for landing on snow." or, "Wheels are extended, skis retracted, for dry runway landing.", or, "Wheels are retracted for landing on water" (for amphibians).

When I train pilots in these various types of planes, I will tell them the I will remind them once, but not a second time, to speak the gear position out loud twice. If they forget again, I'll call a late "Go around" with urgency, simply to startle them less then landing with the wrong gear position selection would have. No other pilot, nor passenger, is going to criticize you for observing and stating the landing gear position. Probably other pilots will think to themselves: "Hmm, I should probably do that too!" - particularly when they realize that wheel/ski planes, and most amphibians do not have any landing gear position warning system - 'cause the plane does not know the surface upon which you intend to land, so it's completely up to you!

Yes.
Can we please stop calling them 'downwind' checks. The term 'pre-landing' checks covers not only the downwind but the base and straight-in joins. I learned this fairly early on when the only joins permitted at my base airfield were left or right base joins, (depending on runway in use) as the airfield was inside the Heathrow Zone. If you're not ever 'downwind' and you've on.ly learned to do the checks 'downwind' then you're not going to do them.
I read recently that every item on the list is there because someone has paid dearly for not doing it.

TOO

Really? Misters Piper, Cessna and Swearingen (I have not flown retractables from anyone else) all have a different opinion on that. E.g. the emergency procedures section in the manual of a Pa28 Arrow, that I have right before me, calls for gear-up emergency landings only in case of very short of soft/wet fields (and ditchings). So there is not one procedure - and especially not one mnemonic - that fits all.

Quite right too. I totally agree. Most ab initio training takes place in fixed gear aeroplanes and therefore it should not be "undercarriage down and locked" as often taught but to be correct "undercarriage - fixed".

I'm not a lover of mnemonics because they too easily become thoughtless. 'bumffpitchh' and forever onward - this one can get longer - is just silly and can only serve as a distraction. If your going to use a mnemonic keep it short, you should know what to do.

In Britain it's a microlight, subject to a lighter touch but still robust approval process. They do not have a significant history of in-flight structural failures.

I have a share of a Bolkow Bo209-150FF Monsun, an aerobatic part 21 CofA aeroplane, that 2 years ago half of the canopy separated from the aeroplane in flight. The pilot, fortunately a very experienced ex-military pilot landed quite safely, but we never did find the canopy. It's presumably under a field near Oxford somewhere. That was a disbonded glue joint.

I'm also aware of a hinged canopy on an EV97 Eurostar SL -a kit built light aircraft - that came open in flight leading to drag greater than the engine could manage and a field landing from Calais airport 4 years ago (there's no official report on that because the French authorities don't investigate accidents on amateur built aeroplanes).

Here's an AAIB report on another kitplane whose canopy came open then detached in flight. The cause was failure to properly secure the canopy catch - something that could readily occur with many certified aeroplanes. There's a good reason for the second H. https://www.gov.uk/aaib-reports/aaib...sling-4-g-ldsa

The obvious explanation for why you want the canopy secure before landing, is that in the event of a hard landing, that could dislodge an improperly secured door or canopy, creating a distraction at a high workload period of the flight.

These things can happen.

G

The Aero AT3 is a part -21 aircraft which has a history of the canopy opening in flight. This is a common event although I have not heard of a canopy detaching from the aeroplane.

The overhead canopy pops into the fuselage by two lugs either side forward of the firewall. There are no conventional hinges. The canopy rotates forward vertically around the lugs assisted by two hydraulic closers, one either side. The canopy must be lowered with care as it twists side to side if not held centrally and therefore can be closed off centre. If this is the case then the locking pins will miss the associated slots at the rear of the opening even though the locking lever can be moved to the locked position. The canopy will not be locked when this happens. This failure to lock cannot be seen and can only be known by pushing outward at the rear pin point on each side. This takes some effort. If the pins have missed the slot the canopy can be pushed outward and this movement can be seen.

TOO , agree strongly on Pre Landing checks ...
A few years ago , a twin coming in for routine maintenace positioned straight in , ...landed wheels up . Major rebuild .
If he'd had joined downwind , I suggest it would not have happened as pilot of the 'Downwind checks era.
Pre Landing in ones mind may have helped .

rgds
condor .

Just follow whatever checklist that is in the POH/POM.... Then you don't have to worry about any special "features" with the aircraft.

I agree with you - but couldn't resist your challenge! https://www.gov.uk/aaib-reports/aaib...ey-m20k-g-osus

Obviously baggage door rather than crew door but food for thought...

The Mooney baggage door opens upward. The door geometry in the open position with respect to the airflow undoubtedly contributed to this incident. If the door had been hinged on the forward side it is extremely unlikely it would have come off.

Bad stuff happens and the take away on this is the same as for any open door FLY THE AIRPLANE FIRST. It is notable that the pilots efforts to stay current and practice emergency procedures paid off when his day went bad.

This thread has drifted around a bit but a few comments on other matters

First I want to reiterate my early comments with respect to an instructor telling a student to abort a takeoff if a cabin door opens “because the door could fall off and hit the aircraft”. I think this is utter rubbish and needs to get stamped out now. As for every abnormal or emergency situation control of the airplane is the most important thing. If there is sufficient runway to come to a safe stop then obviously do that, sort the door and set up for a second takeoff attempt. If there is doubt about stopping then continue the takeoff fly a circuit land and sort the door.

However as I also specified, this advice is intended for the normal certified light aircraft found at flight schools and flying clubs. If you are flying some bizarre type like an ultralight helicopter or some sort of flying lawn furniture, then I would suggest a type specific evaluation of potential emergency situations is needed and a plan for each one is clear in your mind. This may involve rejecting every takeoff with an open door even if it means crashing off the end of the runway because the aircraft will be uncontrollable with an open door.

With respect to landing gear up for a forced approach, I should have been more specific. My advice to always land gear up was for types that had no specific direction in their POH. Obviously follow the POH advice first. However it should be noted that the POH advice, like that in Piper retractables usually starts with a caution that the pilot needs to evaluate every scenario. The reason for the recommendation for a gear up landing was to reduce the chance of the aircraft cartwheeling or overturning.

There are disadvantages to putting the gear down for a forced approach. In some airplanes, if the engine is seized the emergency gear lowering procedure would have to be used. I would suggest after the engine fails you have enough on your plate already. Also the extra drag of the gear will alter the glide flight path significantly. If you have the field nicely made I would suggest you not mess with success

Finally “Downwind Checks” should IMO be banished from the flight training lexicon and only the term “Prelanding Check” be used for the reasons pointed out by earlier posters.

I was taught to fly 50years ago, SEP, the “downwind” checks I learned then are firmly imprinted in my mind, I always do them downwind when flying the same simple types, Cessna, PA28 etc. I think it would be unwise of me to change these habits now which have stood me in good stead until now.
Yes, I include “gear down and locked” even on a fixed gear aeroplane.

[QUOTE=Meldrew;11008225]I was taught to fly 50years ago, SEP, the “downwind” checks I learned then are firmly imprinted in my mind, I always do them,..........
Me too 50+ years now and still push an imaginary u/c down as l do the checks.
After all you never knew when one day you might be in a folding u/c aeroplane. I even still say "pitch set to fine"
Why not, even if only to be consistent, it only consumes a few seconds.

In the modern world we don't always join downwind, other than, of cause, at uncontrolled airfields. At controlled aerodromes it is usual to be cleared via the most direct route. This also has an environment benefit by spreading the noise intensity away from one place. I too agree that the term 'pre-landing is therefore most appropriate.

This is wrong. Repetitive checks with no purpose is just that. Some years ago I was checking out a friend, a Captain of a large jet, on a simple PA28. He had approximately 4000 hours instructing on club aircraft from some years earlier. During the circuit work his verbal checks were perfect with well synchronized touch controls. Other than a few issues with the round out, but never unsafe, I introduced a few problems. Having distracted him I pulled the mixture control by a few inches and switched to one magneto. Once again the checks were perfect but neither of these were corrected. When I pointed this out he was furious but not with me rather with himself. He undertook to take this back to work for discussion, I had obviously struck a nerve. I on the other hand incorporated all that as safely as I could to bring actual reality into the checks with all my students. Some things are quite simple: adjusting the altimeter, altering the HI by 30 degrees, demanding that when Ts and Ps are said then the actual temperature and the pressure is read out. Are the brakes actually fully off: i.e. C150 trained pilots press the top of the brakes even when flying a C172 which has a hand brake.

With regard to "gear down and locked and pitch fully fine". There is nothing more likely to wind up the neighbors than: a constant speed propeller, at fine pitch, screaming along the length of the downwind leg, as it fights against the lowered undercarriage drag.

"Red - Blue - Green" Checked at around 500' on approach has saved me on a number of occasions.

I agree. A "check" is [hopefully] a "second look" confirmation that something appropriate to a phase of flight, has been correctly accomplished. If it's not appropriate, why do it? Prop to fine pitch? Appropriate on short final when the power is back. I agree, that in a potentially noise sensitive environment, whining along downwind does nothing beneficial. "Landing gear down"? Yes, appropriate if you're going to land a wheelplane on a suitable runway. So, that makes "Landing gear down for a runway landing" an appropriate checklist readback (which I insist on hearing out loud - or it's a go around). Because, you could be landing an RG in circumstances where having the landing gear retracted is going to work out better. Perhaps (probably) that will be a more task intensive landing, so blinding following rote of "Gear down" is likely to get you into trouble.

Nearly everything in a GA plane can wait the one or two seconds needed to pause and think about what you're doing. You have those couple of seconds to do it with forethought and logic, not just rote, then think back, or read back what you have checked. When I'm flying a plane with checklist items not required for that flight, (a recent example, a survey Caravan with many survey items on the checklist, when I'm not doing survey flying in it), I'll read the item, and respond "not required", rather than skipping it. That would also apply to flying an airplane with "landing gear" as a checklist item, when it's configured as a fixed gear plane.

A common and wise response to these questions is always abide by the aircraft's POH/Manual. So, I've looked at a number of these today. I have yet to come across a POH that mentions "downwind" in any section. The terms used are variously; 'Pre-landing', 'before landing' and with one referring only to 'final' and 'short final' (neither of these terms are defined as a distance from landing).

Like most posters I've had doors come open in a number of small types (PA34, PA44, PA28R, various Cessnas) with no issue. By far the biggest risk is distraction. This also applies to malfunctioning door open sensors in Diamonds.

I sometimes fly an aircraft with a sliding canopy. It's certified but not too common. There is an unwritten SOP that for this type, when operating somewhere quiet with nobody else in attendance (to help extract you or call the fire brigade), we take off and land with the canopy fixed open (below about 500ft).
The idea is that if one had a problem and had to land in a rough field or long grass and flipped over, it would be pretty hard to get out unassisted with the canopy closed.
The aircraft also has an "E.E.D" (emergency escape device = Homebase claw hammer) for such purposes. The forced landing and ditching checklists have "canopy fixed open" on them, too.
I guess other types with canopies like Chipmunks and so on are similar?

I would not disagree with most of the comments made already. However my personal view is that assuming a normal circuit is being flown, downwind is the time to do the “pre landing checks” On base leg I am configuring flap and trimming for correct airspeed, and on final I am concentrating on runway alignment and correcting for crosswind. This is no time to be doing the checks. I accept that variations are required when flying a non standard approach or a straight in.